Dan Pratt
Hadley, Massachusetts
Mixed vegetables
Occultation, mulch grown in place, and applied organic mulches
UNFORTUNATELY FOR ME I HADN’T YET HEARD OF Astarte Farm when I was swinging through Massachusetts doing farm visits, or I would have tried to stop by for an interview during the growing season. It wasn’t until it was snowing that someone asked me if I had visited Astarte on my quest to interview no-tillers.
So I got ahold of Dan Pratt, and he was kind enough to talk to me about his experience with no-till over the phone in January while the farm was under a blanket of snow.
“I no longer own the farm. I sold it three years ago, but I was lucky to be quickly hired as the farm manager. The whole property is 6.6 acres, but with a house and three barns, and the mandatory buffer zone for the organic certification, we’re growing on about three and a half acres,” said Dan. “We have a heated propagation greenhouse, 26' by 48'. We have three high tunnels of varying sizes. We have about 85 production beds that we rotate our crops through. The beds are 175' × 3' with 3' pathways between beds. The pathways are either mown weeds or cardboard with wood chip mulch.”
Dan, who was already an experienced farmer, bought the farm in 1999 and sold it in 2013. Ever since, he has been working to encourage long-term fertility by using biochar, pollinator and predator habitats, and no-till.
“How did you get interested in no-till in the first place — you started out doing more of a conventional tilling system, correct?” I asked.
“Yes, in a sense. I started out with a little Italian spader, a 36-inch Tortella model. The rumor was that spading was much easier on your soil structure, and might not completely obliterate your earthworm population, because it wasn’t churning the soil and inverting the soil profile. I started doing semi-permanent production beds, where we would run the tiller, and then we had grass or weed paths that were undisturbed,” said Dan.
I know the spader well, because when I realized that roller-crimper no-till didn’t scale down to my original farm, I bought one in an attempt to avoid some of the problems with repeated rototilling. It’s called a spader because it has a row of miniature shovels that dig into the ground and throw a chunk of soil against a back plate to pulverize it by impact, instead of by churning the soil under like a rototiller.
“It was roughly a three-foot path, and a three-foot tilled bed, and a three-foot path, and on like that, thinking that at some point, I would let everything switch [from beds to paths and vice versa] over so I’d be able to get into that fallow ground in five years. But the fact of the matter was that after five years of growing and mowing weeds, I had a weed seed bank in those paths to beat the band,” said Dan.
“So whenever I would turn one of those paths, I faced really tremendous weed pressure. The spader was a pretty good little tool, but what I noticed after about six or seven years of doing this was that my grass paths, which had just been mown, were rising, and even though the production bed would look like chocolate cake after you’d run the spader through there — fluffy, wonderful soil, easy to transplant into, great for direct seeding — after a couple of good, hard rains, the production beds were sinking two, three, and four inches below what had been in sod.
“And then I heard Elaine Ingham at one of the NOFA summer conferences. This really caught my attention because of her talk about soil organic matter, and having everything you needed in the soil. We’re lucky to be in this Connecticut River Valley. We’re farming the bottom of an old lakebed. There used to be an ice plug in the Holyoke Range that held back a lake for ten thousand years. This soil is probably some of the best soil in the world.
Getting ready to roll down some winter rye with a front tractor mounted roller-crimper.
Credit: Dan Pratt
“I mean, if you find a rock out in our field, you know somebody carried it out there and dropped it. It’s super easy to work with, but here was this evidence in front of my eyes. I don’t really do a lot of soil testing, but I do it every two or three years. I was just staying flat on my organic matter, even though I was adding compost and cover cropping in the winter. I was just going in there with that little spader and tearing up everything that was trying to get established in the soil. I foolishly thought that these grass paths would be like refuge strips, a place for the earthworms to go scurry off into when the spader’s coming,” said Dan.
“It was a bit of a leap of faith to just say, ‘Well, let’s see what we can do with this. Let’s give it a shot.’ We started out with a fall garlic planting. We wanted to use buckwheat as the smother crop, but it was one of those falls when you could not get buckwheat to die, because we didn’t have a killing frost in the fall. We ended up mowing it multiple times with a little mulching mower, which was laborious, and then laid down a couple inches of compost. After that we used Weed Guard Plus paper mulch,” said Dan.
“The paper was pre-punched at seven and a half inches in three rows, with a total 36-inch width, so we just laid that down right on top of that two inches of compost and held down the edges with aged wood chips. Then we poked our garlic cloves through the holes, laid about an inch of compost on top of the paper to keep it from blowing away, and we were off and running.”
“So you didn’t even try to get the cloves down into the soil? You just poked them into the compost, you didn’t try to get them into the soil underneath?” I asked.
“No, we just pushed them in as far as they would go through the compost and mowed buckwheat, that was as far as we went with it. I’d like to emphasize using the wood chips to hold down the paper edges as we rolled it out. Because we’re in a windy location, we have to be really careful with that paper. It would like to travel two states if we gave it a chance in a breeze,” said Dan.
I just hate to see us continuing to do this much violence to our soils. It sounds almost sentimental or something, but when you’ve treated a piece of land right for a little bit, you begin to see so much more life.
—DAN PRATT
“We had a great garlic crop that came off those first no-till plantings. That was interesting to see as we were just still getting started with no-till. We hadn’t fully committed the whole farm to it, but when we pulled that crop around July 15th, we were able to replant lettuce transplants right into that bed because it was virtually weed free.
“We had a banging crop of lettuce, and just went right ahead and planted lettuce again, and we had a very good second crop of lettuce off those same six beds. That kind of sparked something in us. There was, I would say 10 percent of the weeding that we’ve ever done before on any production bed at the end of that full year. So it was the second crop that needed the most hand weeding. The first one basically just went in and we were golden. That’s how we got started,” said Dan.
“Was it weed seeds that blew into that second crop, or was it perennials that eventually came up through the layers of compost and paper that you had put down?” I asked.
Beds after occultation in the foreground, and during in the background.
Credit: Dan Pratt
“Well, when you pull your garlic out of the ground, you’re always pulling some dirt up on those long roots. We always try to shake them as we pull them up, try to keep all the dirt in place, but some always comes up. Then, when you have a crew out there transplanting, there’s always somebody that flicks some dirt out on top of the compost. We’re very well surrounded by conventional growers, and a lot of times when the sweet corn’s been picked, well, that’s it for that field until they put their fall cover on, so there’s plenty of weed seed blowing around in the valley as well,” said Dan.
“Pretty quickly, we ended up with a very small roller-crimper [based] on that Rodale model. We had it mounted on a quick-hitch plate where the loader would be on our little Kubota tractor. Which was pretty sweet, because then you could lift the front wheels off [the ground], to maximize downward pressure and avoid having to fill the drum with water. We use the individual [wheel] brakes to steer. The thing that we ran into, and it was probably the second year when we were doing no-till, was the root mass that we had left over from the winter rye was just about impenetrable,” said Dan.
“We had really nice, sharp soil knives to cut our little holes for transplanting into, and after the first half-dozen beds, the crew said, ‘If you ever plant winter rye again, you’re looking for some different people to transplant because that’s ridiculously hard.’ And it really was.
“We should have known that from our experience tilling in winter rye with the little spader. If you let that rye get up over knee high, you were looking at a real job and a half. Because it would just break up into clumps, and the clumps, all or half of them, started growing again, you’d be spading two and three times if you let that rye get very tall.
“What we have used the roller-crimper for with some success is on our cover crop cocktails where we’ve got oats, peas, and radish together, for instance. We can seed that in the spring and grow it for mid-season crops and have pretty good luck planting right into that. A lot of times, we are putting in a four-inch pot. I have to be clear about that. We don’t do that very often for our smaller lettuce transplants or anything,” said Dan.
“So you’re planting larger transplants like tomatoes or winter squash into crimped oats, peas, and radishes?” I asked.
“Yes,” said Dan.
“I’m kind of surprised that the roller-crimping is killing the radish. It sounds like it does?” I asked.
“Well, mostly the radish we’re using is in the late summer and fall, so in the early spring, we’re just doing oats and peas. And it is killing them pretty well. I did kill some radish, one season when it was so wicked dry that we couldn’t get oats to germinate, so I got ahold of some teff seed, and we were using teff and radishes. This is prior to a garlic crop. The teff, I swear, that germinates in dust. I don’t know how it does it, but it does it. We had a lovely teff stand, which was frost-sensitive, but in our enthusiasm to do this, we had all those daikon radish out there that didn’t kill,” said Dan.
“But when the radishes had pushed out of the ground three to four inches, and then you run the crimper over them, it pretty well breaks them all off. I think I probably had to go back down the row and whack a few with the side of a shovel that didn’t break off completely, but it was fairly effective,” said Dan.
“Okay. Is that a pretty regular thing for you now? It sounds like you’re using the roller-crimper for transplants only?” I asked.
“Yes.”
“That was my impression. What I came away with after working with that style is that it was great for transplants, but you’re not going to direct seed salad mix into a bed that you roller-crimped,” I said.
“Right, I’d say that’s correct,” said Dan.
Adding compost post-occultation with the drop spreader.
Credit: Dan Pratt
“Really the only problem that we had with those spring cover crops that we put in is timing. We had two lettuce beds that were going in that had the same cover crop seeding date. One of them got rolled on the correct date, and one of them, for weather or vacations or whatever, didn’t get rolled for another ten days. [On the bed that didn’t get rolled on time], we had a regrowth of the oats that was substantial, and we basically ended up with miniature lettuce heads growing in a forest of oats. We were lucky to have a deli that would take those little heads for their salad bar. We didn’t lose all our money on it and that was one bed we didn’t have to re-seed [after the cash crop], let me put it that way,” said Dan.
“That’s one of the other limitations with crimping, that you have to be on top of your timing because you have limited planting windows. If you miss rolling at the right time or planting at the right time, you either get regrowth of the cover crop or you don’t get enough weed suppression,” I said.
“On my wish list for this year is a flail mower,” said Dan.
“So you can just drop a cover crop in place?” I asked.
“Yes. I don’t know if it’s going to chop things too finely to make an effective mulch. It may require using paper mulch again if that’s the case, that it’s just chopped too fine to provide any weed suppression, but I would like to try running a four-foot flail mower down some of these really nice, lush cover crop beds and see what kind of a seedbed we get from that,” said Dan.
“A lot of these guys, like Bryan [O’Hara] (see interview p. 305) and Ricky [Baruc] (see interview p. 81) have figured out these systems that really work for them, and we are still feeling our way into this.
“I would like to say in all confidence, I know that this is going to work. But after three years, the soil hasn’t softened up as much as I expected it to, and we’ve certainly used enough compost as mulch and other things. We’ve completely abandoned using all blended organic fertilizers, and we’re still getting really good growth and yields. There are pluses and minuses, but I wouldn’t say we’re the experts in this by any stretch in the imagination.”
“We have some grass paths left, but we got sick of doing all that mowing. There’s always that month period where once a week isn’t enough, and because we wanted to do as little cultivation as possible, the intrusion of the grasses just countered the whole thing we were working on,” said Dan.
“We had gone to putting down nice, clean cardboard and using wood chips to hold it down. Our biggest limitation has been finding clean cardboard. By that, I mean because we’re certified organic, we can’t have any cardboard with colored printing on it.”
“Black is okay?” I asked.
“Yes. Black is carbon-based ink, but any kind of color doesn’t meet the national organic standards,” said Dan.
“We bought a little ABI Elite spreader that’s a hydraulic drive spreader, and we could lay down as little as a half inch, or as much as two inches of compost, in just a straight drop pattern.”
“And that’s a drop spreader?” I asked.
“Yes. ABI is the manufacturer. Their elite model is a manure spreader for small to mid-size stables. It has a hopper that holds about two and a half yards. Because it’s hydraulically driven, instead of ground driven, by varying the motor speed and your ground speed on the tractor, you can really adjust it to drop the amount that you want. Because it drops straight down, it’s not being spread out all over the paths. It’s really been a sweet tool for us,” said Dan.
“We used to do all our spreading by hand, just two people walking backwards in front of the tractor with shovels. It was ridiculous, the amount of time they were waiting around in the field while I was getting one more bucket of compost. That spreader turns a three-person operation into a one-person operation.”
“So you said you’re using occultation, and you’re using solarization, too?” I asked.
A young cover crop of oats broadcast by hand onto compost spread on a previously occulted bed, then five rows of field peas were planted with an Earthway push seeder.
Credit: Dan Pratt
“We did our first major solarization this last summer. It’s not quite a quarter acre, but it’s a fairly large patch that cuts across our field that’s going to be all perennial flowering shrubs. Perennial flowers specifically for beneficial habitat,” said Dan.
“But you’re using the landscape fabric for occultation for annual crops?” I asked.
“Yes, that’s correct. We probably have ten strips out there right now under the snow that will be the early spring plantings. We rotate them right through the field. We have 85 production beds, we’ll rotate those through. Sometimes, we use it on top of a rolled strip if we’re not going to get a chance to plant into it quickly enough,” said Dan.
“Kind of a placeholder?” I asked.
“Yeah, just as a placeholder. It keeps any weed germination from happening. We really like the porous aspect of the ground cloth strips, the fact that rain goes right through it, oxygen goes through it. We use it, for instance, in the high tunnels after we’ve harvested the crop instead of pulling the plants. Let’s say we had early peas. Instead of pulling the peas, we’ll either cut them or just mash them down and roll an occultation strip out on top of that, and it makes a lovely seedbed to plant into. Again, we mostly use transplants when there are a lot of crop residues,” said Dan, “but occasionally we will just rake the residues onto the bed shoulders, drop some fresh compost and direct seed into that.”
“How long do you have to leave that on before you’re going to get that lovely seedbed?” I asked.
“It really depends on the season.”
“Shorter in the summertime, longer in the fall?”
“Yeah. We’ve had them out probably for close to five months over the winter, and in some cases [in warmer weather], we’re able to get them up in three weeks. Basically, we just go down and keep peeking under there to see what we got,” said Dan.
“When you go from one crop, let’s say the peas, and you’re going to put a tarp down for a few weeks before planting into something else, you said you got away from the blended organic fertilizers. Are you pulling the tarp off and then putting some compost on before planting the following crop, or how do you handle that?” I asked.
“We’ve definitely done it both ways. We’ve applied compost and put a tarp on, or an occultation strip, and we’ve done it after pulling the strip off. It really depends on what’s available in terms of manpower and how much compost we have on hand, et cetera,” said Dan.
“The only other thing that I’m thinking that might be of interest is the way we tend to seed our summer covers. If we’ve had a spring crop, let’s say it’s lettuce, and we cut the lettuce at the soil level so we’ve got a flat bed, we’ll go in there with the ABI spreader and try to lay down a nice, even two-inch compost layer on top of the bed. Then we’ll hand-broadcast oats on top of that compost, and not even attempt to cover it at all.
“But when we put our peas in, we use the old trusty, Earthway [seeder] through there with the peas, and that little tiny shoe throws enough compost on top of the oats to get germination, and we can do three rows of peas down the middle of a three-foot bed and a row on each edge of radish, if we want to have radish in there if it’s for a fall planting. It just does a super job.”
“That’s a good tip.”
“Not a no-till planter, but works just as well,” said Dan.
“Just by planting into the loose compost on top?” I asked.
“Yes. We’ve tried to rig a piece of equipment with a couple of old hilling disks on a frame. That was the first year when we had that really heavy winter rye cover, and the crew wasn’t happy trying to transplant right into it. We tried setting that up where it would cut two furrows, 18 inches apart through the rye, and then run the Earthway in there and plant large-seeded crops. But I don’t know if it was because I didn’t have the wavy coulters, or I didn’t have enough weight on it, and those roots just wouldn’t allow the thing to cut properly. We never really had any luck doing direct seeding that way,” said Dan.
“Have you gone completely over to no-till? Are you no-tilling parts and still spading certain parts?” I asked.
“We don’t use the spading machine for anything except for a wheel weight when we’re plowing snow in the winter,” said Dan.
“So is it correct to say that you’re handling all your planting needs by either the method you were planting your garlic, with the big compost applications and planting paper, or occultation?” I asked.
“Yes, we’re 100 percent no-till now.”
“Okay. It’s interesting that you made the transition over time,” I said. “Is there anything I should have asked you, or anything else you’d like to say about it?”
“There’s probably a lot more I’d like to say about it. I just hate to see us continuing to do this much violence to our soils. It sounds almost sentimental or something, but when you’ve treated a piece of land right for a little bit, you begin to see so much more life. The amount of spontaneous mushroom fruiting that we get on our farm after just three years of this is really very, very encouraging to me,” said Dan.
“I think one of the biggest side effects of all the tillage and cultivation we’ve done is ending up with these bacterially dominated soils. And the mushrooms are where the really neat stuff around the root hairs happens. The more of that we can get going, the happier the whole scene is going to be.”
“Are you taking any steps in addition to no-till to try and encourage the fungal aspect of the soil?” I asked.
“We’ve used powdered mycorrhizal inoculant. We spent a lot of time pre-inoculating some of our biochar when we first got started with that,” said Dan.
Planting tomatoes into a crimped cover crop.
Credit: Dan Pratt
“I was telling you how great this soil is in Hadley, but after probably twenty years, the twenty years prior to us buying the place, there were just giant disc harrows run over the field twice a year, once in the spring, once in the fall. Every time it was going down to the same depth. The first crop of carrots that we grew on the farm, they all grew down six inches and took a left-hand turn. They came out like little Js. We had standing water in the field, and this is really some well-drained soil that we’ve got, but it was just a plow or disc pan that was under there. That pan has now all been broken up by earthworm tunnels, and ground beetles, and some deep-rooted weed crops too, I’m sure. I’m one of those people that likes to see a dandelion because I know what’s going on deep down in there.
“And we don’t have any standing water on the farm at all. It’s just good to see those macro results, if you will, and know that that’s a result of a lot of microactivity,” said Dan.
Shawn Jadrnicek
Chester, South Carolina
Mixed vegetables
Mulch grown in place with added leaf mulch
I CALLED SHAWN JADRNICEK ON A BUSY DAY BETWEEN spring rains. I wanted to talk to him because he has made innovations in the roller-crimper style of no-till that are important for growers wanting to use this system.
Shawn is the manager of Wild Hope Farm, and he’s done a lot of things over the years — he’s been a farmer, extension agent, arborist, and landscaper, among other things. Which may be why he is such an original agricultural thinker: He’s seen things from so many different perspectives that he brings a new approach to the age-old agricultural problems. Like how to deal with weeds, for example.
I became a fan of Shawn’s because of his excellent book The Bio-Integrated Farm. In addition to other agricultural innovations, he talks about how he uses crimped cover crops to suppress weeds (see p. 283–85 of his book for Shawn’s description of his no-till method). I was especially excited when he sent me an article for Growing for Market magazine about some modifications he made to the crimped cover crop system that helped extend the weed-free period.
Since I already had a description of his system in his own words, he was kind enough to allow me to republish the article as a part of this book. But I had some questions about the method so I wanted to check in with him about what he was doing.
“Would you tell me a little bit about Wild Hope Farm?” I asked.
“It’s 212 acres, we basically just started farming it last July. It’s in Chester, South Carolina, and it’s owned by the Belk family, Tim and Sarah. Right now, we’re primarily vegetable production. Our main market is CSA. This year we’re putting three and a half acres into vegetables,” said Shawn.
“And we have pastured hens on another few acres, that are rotating through some cover crops that we planted. Eventually we’re planning on expanding up to about eleven acres of vegetables and adding sheep and cows, and pigs to rotate through the fields. This year, our goal is to have a 100-share CSA, and we’re hoping to expand to a 400-share CSA over time. We also sell to restaurants, and we’re selling at a farmers market as well.”
A mechanical transplanter with water barrel planting into crimped cereal rye. The mechanical transplanter requires transplants sized at 1.5” and works best with the Speedling transplant trays. With Speedling trays the transplants are pulled out from the top without poking them out the bottom so you can move at a good speed. It’s important to have strong transplants that are fully grown and have completely filled out the cells.
Credit: Shawn Jadrnicek
“And are you doing a lot of that no-till, with the techniques you described in the article?” I asked.
“Yes, absolutely. We’re actually getting our roller-crimper at the end of this month. So it’ll be here just in time for our main crimping operation. When I worked at Clemson University, I had an amazing free resource of leaves. We were inside the city limits, and it was more convenient for the city to drop the leaves at the farm,” said Shawn.
“So now, I’m having a harder [time sourcing leaves]. We’re just a little too far out of Chester’s town limits. So we hired someone with a dump truck to bring the leaves out to the farm. We paid about $5.50 per cubic yard, and paid another $400 for delivery — that’s the cheapest way. But we’re also planning a logging operation on the farm. We’re hoping to get about 1,200 cubic yards of wood chips from that, which we will incorporate into our no-till system.
“I’ve only used leaves with the system, I’ve never combined wood chips, so it will be interesting to see how wood chips work out.”
“Well, I was really impressed with your no-till system, that you figured out how to take the roller-crimper and improve the length of weed suppression by incorporating leaves as mulch. And remind me, are you chopping those leaves up before you’re using them as mulch?” I asked.
“The city has a machine that shreds them as they vacuum them up into the dump truck. So they do come shredded,” said Shawn.
“Oh that’s handy.”
“Yes, it does seem to help, otherwise they blow around too much,” said Shawn.
“I interviewed some other people who were using leaves as mulch, and they were pretty adamant about shredding them. How did you hear about the whole roller-crimper thing? I’m always curious where people got their ideas from,” I asked.
“It’s funny, because I first tried no-till about twenty years ago, way before the roller-crimper was invented. [People] were doing it with undercutters, that was kind of a new innovation, I was doing it with a sickle-bar mower. I would just cut the cover crops with the sickle-bar mower when mature, and then I would rake them into these bundles, and plant my seeds or transplants right next to the bundles. It was kind of time-consuming and I was only farming on a two-acre scale. But then I ended up getting out of farming and becoming an extension agent,” said Shawn.
“[And I heard about the roller-crimper method.] I think it was a Carolina Farm Stewardship Association conference, and they had invited Jeff Moyer [now the Executive Director of the Rodale Institute] down to give a special talk just to the extension agents. As I was talking with him about it, I thought, ‘This is the best thing that’s ever happened to agriculture.’ And it really inspired me to get back into farming after seeing what he invented, and what they were doing. I was so excited about that, it just solves all these problems that I experienced.
“I can’t remember what year that was, or when he came down to give that talk, but it just blew my mind when I first saw that.”
A field a few weeks after mechanical transplanting winter squash, cantaloupe, watermelon, and summer squash into crimped cereal rye.
Credit: Shawn Jadrnicek
The same field as above in a later stage.
Credit: Shawn Jadrnicek
“So is the article still pretty consistent with what you’re doing now?” I said.
“Yeah, everything is still exactly what I’m doing now,” said Shawn.
“For the roller-crimper, it has to be a specific scale. I think you’re right about that. Because the edges of the crimped areas usually get weedy with a no-till system, you lose about five feet around the edge of wherever you’re crimping. So I try to crimp as large an area as possible at a time, making the blocks as wide as possible. But of course if you’re adding leaves then it doesn’t really matter, because leaves make it perfect everywhere,” said Shawn.
Harvesting eggplant from a no-till field with leaves added using a manure spreader to improve weed suppression. Less than two hours of hand weeding was needed in this half acre plot over the entire season.
Credit: Shawn Jadrnicek
“I thought that was a really nifty thing you did with the leaf mulch. Because I know when we were using the roller-crimper system at Virginia Tech, one of the challenges was, if the cover crop wasn’t dense enough, then it wouldn’t suppress weeds for long enough. Is there any advice you would give to someone trying to get started with roller-crimper no-till?” I asked.
“Definitely, plant your cover crop at the right density and at the right time. And I think the key is really making sure that your cover crop has enough fertility to it. Even if you have the right planting density, but your soil isn’t fertile enough, you don’t have enough nitrogen mainly, the cover crop is going to be scraggly,” said Shawn.
“That happened to me this year, where the fertility was drastically different in the upper half of a field than the lower half. So I got this beautiful, dense, lush green cover crop on one side, and then the upper side is small and scraggly. Normally, that would freak me out because it’s going to be difficult to separate the field into two areas, and it’s already too late to not no-till. [After a certain point] you’re committed to no-till because it’s too late to till and prep soil and get ready for planting.
“But I have all of this leaf mulch on hand, so no big deal. I’m just going to slow the tractor down and apply a little more leaves in weak cover crop areas. Short-season crops won’t get any leaves when the cover crop is dense and long-season crops get leaves regardless. Adding leaves with the manure spreader allows you to fine-tune your whole system and make it applicable to a wide variety of crops, even with a weak cover crop.
“I would probably only do organic no-till with winter squash, summer squash, tomatoes, and cucumbers if I didn’t have the ability to add leaves. Everything else requires a longer growing season, like watermelons, cantaloupe, sweet potatoes, peppers, and eggplant. So really, unless you have the ability to beef up [the roller-crimped mulch] and add some leaves to that, it won’t be easy to do [those longer-season crops], because they will get weedy later in the year.
“The [additional leaf mulch] allows us to increase the amount of no-till that we do drastically. I think at Clemson, my last year there, almost 70 percent of our crops were done no-till.”
This article originally appeared in the September 2017 issue of Growing for Market
Advanced No-Till Mulching
and Crimping Techniques
by Shawn Jadrnicek
Organic no-till and mulching systems are a huge time-saver on our farm. They’ve allowed us to increase production while reducing labor on our six acres of vegetable production. This spring was our easiest year yet even though an illness in April made it difficult to leave the house. I owe the time savings to the roller-crimper.
The roller-crimper is a heavy metal drum with dull blades that rolls over cover crops, lying them flat and crimping the stems to help kill them. The cover crop remains as a weed-suppressing and water-conserving mulch and transplants or seeds are planted through the mulch without tillage. However, for crimping to work, the cover crop must be mature, limiting the technique to several weeks during the spring. In addition, weeds are only suppressed for six weeks preventing no-till from working with long-season crops like eggplant and peppers.
From left, a planting of tomatoes, eggplant, peppers, beans, and sweet potatoes planted into crimped cereal rye. Two inches of leaves were added to the eggplant and pepper bed using a manure spreader to extend the weed control. One inch of leaves were added to the beans and sweet potatoes because they were planted four weeks after crimping and Shawn needed to keep them weed free a little longer but not as long as the eggplant and peppers.
Credit: Shawn Jadrnicek
I’ve invented several techniques to make organic no-till more widely adaptable for farms, overcoming some of the hurdles of organic no-till along the way. In the first technique, I plant cover crops on tractor-pulled raised beds and terminate them with a traditional roller-crimper. The raised beds appear to promote early maturity and better cover crop and subsequent cash crop growth in our loamy soils. The second technique delays cereal rye maturity by up to two weeks, extending the planting time frame for no-till. I use a manure spreader in a third technique to add leaf mulch to the crimped cover crop, extending the weed suppression time frame from six weeks to six months. And a fourth technique crimps cereal rye cover crops up to two months earlier by adding leaves on top to prevent regrowth. By combining all of these techniques, I can grow nearly all our crops using organic no-till or mulching systems.
Weed-Free Cover Crops in Raised Beds
The first step to a successful no-till program is growing a weed-free, vigorous cover crop. To do this, I plant all my cover crops into a raised stale seedbed. First, I make the raised beds using a tractor-drawn bed shaper. If fertility is needed, I add the fertilizer prior to making the raised beds or grow a leguminous cover crop prior to making the raised beds. Next, to make a stale seedbed, I wait for at least a half an inch of rainfall or irrigate the field thoroughly. The rain promotes weed seed growth on the raised beds. Once the beds have dried enough to cultivate, I bring the tractor cultivation equipment over the raised beds to kill the weeds. The cultivation toolbar is equipped with sweeps and side wings for the furrows, crescent hoes for the sides of the raised beds, and S-tines for the tops. The idea is to cultivate as shallowly as possible to kill any weeds without bringing up more weed seeds from deeper in the soil. Stale seedbedding once works well, but twice is best.
I perform the last stale seedbedding when the moisture in the soil is just dry enough to perform the cultivation. I then wait between 4–12 hours to ensure the weeds have died from cultivation then plant into moisture. I apply the seeds with a spinner spreader or bag seeder and then re-bed with the bed shaper to incorporate the seeds.
I read about “planting into moisture,” but never understood how powerful this technique is when performed after stale seedbedding. Stale seedbedding dries out the surface and leaves the soil loose and unable to give the seed-to-soil contact needed for germination. Cover crop seed planted into the moisture beneath the dry soil surface germinates, while the weed seeds on the surface sit idle from the dry stale seedbed. The cover crop seeds then start growing before the next rain occurs, getting a huge head start on the weed seeds. Once the cover crop starts growing, the plants release weed fighting allelopathic chemicals preventing weed seed germination. The chemicals combined with stale seed-bedding create a completely weed-free cover crop.
Cover crop seed selection, planting density, and timing also play critical factors. For winter cover crops terminated in spring, I plant a cereal rye variety called Abruzzi at 150 pounds per acre. I plant the cereal rye six months before our first fall frost date. Planting early gets the cereal rye going before fall cool season weeds start growth. Some of the summer weeds may germinate, but the first frost will kill them before they set seed. Planting earlier or later creates problems with either the warm- or cool-season weed groups. If nitrogen is needed, I’ve added crimson clover. However, clover breaks down quickly, possibly decreasing weed suppression when used as a mulch. I now add nitrogen to cereal rye before planting by growing a cowpea cover crop. For summer cover crops to be crimped, I use Japanese millet at 30 pounds per acre combined with sunn hemp at 50 pounds per acre and focus on stale seedbedding preferably twice before planting. I crimp the summer cover crop mix according to millet maturity.
Extending Weed Suppression
Since crimped cover crops only suppress weeds for six weeks, they work best with fast-growing crops like winter squash, summer squash, and cucumbers. Longer-season crops like tomatoes, eggplant, peppers, sweet potatoes, cantaloupes, and watermelons grow for such a long period of time that weeds eventually intrude, creating a mess. To solve this problem, I add a layer of leaves to the crimped mulch to extend the weed suppression. The leaves are delivered free from the adjacent city in trucks. The trucks vacuum, shred and compile the leaves into specialized dumping bins holding over ten cubic yards. Once stockpiled, our 125-bushel PTO driven manure spreader then applies two inches of leaves over a quarter acre in two hours. Two inches added to crimped cereal rye gives around six months of weed control depending on cover crop density. Adjust down depending on the crop planted into the mulch, but even one inch will drastically improve weed control and help fill in weak areas in the cover crop.
To extend the weed suppression in no-till with mulch, I first crimp the cover crop, then let it dry out for a few days to become carbonaceous and resistant to decay. Leaves are then applied before or after planting transplants. When applied on top of plants, I unbury the plants by hand after application. Also, some plants such as peppers don’t like mulch up against their stems, so I carefully pull it back. Be prepared for mulch to delay plant maturity by about one week.
Mulching with a Manure Spreader
Manure spreaders apply mulch quickly and evenly over the soil, making them the perfect mulching machines. However, our ABI manure spreader is slightly wider than our tractor. When we make raised beds this means that the tires on the manure spreader don’t follow the tractor furrows but travel along the edge of the adjacent raised beds. Depending on planting arrangement, raised beds may need wider spacing to accommodate the manure spreader.
Applying leaves on top of crimped cover crops means a small amount of leaves can make a big difference. However, applying leaves on bare soil in larger amounts works well for weed suppression and has many applications. With garlic, I plant three rows per raised bed into bare soil. Just prior to the garlic emerging, I add four inches of leaves to smother the weeds. The garlic pushes through the leaves and the weeds never have a chance.
This saves us around forty hours of weeding in our one-fourth acre of garlic. With potatoes, leaves applied prior to sprouting will prevent weeds and conserve moisture, but also delay potato emergence and maturity. For early emergence and maturity in potatoes, apply leaves after the first cultivation or hilling. Storage onions are the final crop I’ve used with leaf mulch alone. I apply a layer of mulch to beds prepared in the fall. The mulch is applied to a four-inch depth and remains fallow without a cover crop through the winter. The leaf mulch keeps the weeds at bay until I’m ready to plant the onions in late winter or early spring. I then plant the sets directly into the leaf mulch or just below the soil because both methods seem to work well and the onions stay weed free until harvest in June.
With early-season plantings of summer squash, cucumbers, and cantaloupe, soil warmth is important. Growing early crops on bare soil for the first few weeks encourages earliness from increased warmth. Delaying leaf mulch application until after the first cultivation takes advantage of bare soil warmth while also providing the benefits of mulch.
One year, it was too wet to get into the field and cultivate the crops. However, a break in the weather dried the field out enough to drive the manure spreader over the plants. I applied the leaf mulch with the manure spreader while the weeds were one inch or less, smothering them. My crops were just tall enough to stay above the layer of leaves and pushed through with a little help. The leaf application saved us from a weedy mess the wet spring would have caused.
Using Leaf Mulch to Crimp Early
Many farming inventions and lessons are happy accidents. This one happened when I crimped a cereal rye and crimson clover cover crop about two weeks earlier than I should have. The cover crop wasn’t mature enough and popped back up, smothering the tomatoes I’d planted. However, I applied leaves to part of the crimped area — and to my surprise the cereal rye stayed down and died and the crimson clover pushed through the leaves and continued to flourish. I realized with this accidental experiment that applying leaves allows early termination of some cover crops.
To better understand the potential of the technique, I performed two replicated trials using four different mulch depths and two different age classes of mulch on top of cereal rye crimped at three different stages of early maturity. The younger leaves were collected in fall and the older leaves were collected from the previous year’s fall. I applied the leaves one, two, four, and six inches deep. My observations indicate that the older leaves worked better at preventing cereal rye regrowth than the younger leaves. I noticed that the wind blew the younger leaves around possibly opening up areas to light. Older leaves congealed together, creating a light-blocking mat. Although the one- and two-inch depth mulch did not prevent cereal rye regrowth, four and six inches of mulch did.
Shawn using a bulb planter to transplant by hand into crimped cereal rye.
Credit: Shawn Jadrnicek
Immature cereal rye is more succulent than mature cereal rye. Because of this, the weight of the crimper must be reduced as much as possible to prevent the crimper blades from cutting through the cereal rye. Once the grass is cut, it easily pokes up through the mulch and continues to grow. I emptied all the water from the crimper to reduce the weight before use. Also, early crimping probably changes nutrient dynamics with decomposition. The succulent nature of the young cereal rye likely promotes a more favorable release of nitrogen for subsequent crops, compared to more mature cereal rye.
I saw little difference in the timing of the early crimped cereal rye. The first crimping occurred Feb 21 when the cereal rye was twenty inches high, just prior to the boot forming (stage 9); the second occurred on March 6, as it was just starting to head (stage 10–10.1); and the third on March 20, when the cereal rye was heading (stage 10.5). The earliest treatment had the most regrowth. However, the crimper weight was too heavy during this treatment and was adjusted for the later treatments.
I also performed a single treatment with two replications on a cover crop of mustard crimped on March 6, just prior to the mustard flowering. With the mustard treatment even the one-inch mulch depth was successful. The control plot that was crimped without adding mulch to the mustard stayed down but weeds quickly invaded.
Three-fourths of an acre of garlic, onions, and potatoes mulched with leaves using a manure spreader required less than one hour of weeding over the entire season. Eight hours was required to apply the leaves with the manure spreader.
Credit: Shawn Jadrnicek
Planting into Mulched Systems
We recently purchased a mechanical transplanter with a no-till attachment to help facilitate planting into the mulched systems, but I haven’t tested it out yet. Previously, transplanting into mulch proved more time-consuming in comparison to bare soil systems, but still saved time in the long run with less tractor work and weeding. Since cereal rye dries the soil out, I pre-irrigate with a drip line if needed to moisten the soil prior to transplanting. I then use trowels or a bulb planter to remove soil in the planting hole for the transplants. The bulb planter is a specialized item from A M Leonard that has the ability to push the plug of soil out without turning the bulb planter upside down to save time. Ideally the bulb planter is the same diameter as the transplant plug.
Planting into the early terminated cereal rye with mulch on top proved more difficult than I expected. When the leaf mulch is moved out of the way to plant into the ground, cereal rye is exposed to sunlight and is difficult to cover back up with the leaves. Once exposed, the cereal rye continues to grow and competes with the adjacent plant. Waiting one to two weeks after applying the leaf mulch on top of the cereal rye ensures that the cereal rye is shaded long enough to kill it. Alternatively, I planted directly into the leaf mulch on top of the cereal rye and this worked the best. The leaves were shredded which helped retain moisture and the older leaves worked better than the younger leaves. Irrigating twice was enough to keep the plants alive during the wet spring we had while conducting the trials. A dedicated drip line for the plants would have alleviated any drought stress I observed.
Cold damage was the biggest issue with crops planted into the early crimped cereal rye with leaf mulch placed on top. The mulch prevented the soil from warming and the kale and broccoli I planted into the system were damaged even though they are cold hardy crops. I didn’t harden the transplants off before transplanting because this hasn’t been an issue when planting into bare soil, but should definitely be done with early crimped systems. The transplants placed directly into the soil under the mulch had more cold damage than the transplants placed into the mulch on top of the soil. Cold air probably settled into the depressions in the mulch made when planting into the ground. In addition, the dark-colored older leaves applied as a mulch showed less cold damage on transplants than the newer leaves, probably because the darker color and denser mulch absorbed more solar energy.
No-till broccoli planted into cereal rye terminated early by applying leaves after crimping.
Credit: Shawn Jadrnicek
Insects, Mulch and Early Crimping
Crops planted in the early spring are notoriously susceptible to cabbage maggots, a tiny fly that lays its eggs on the soil near plants. The fly larvae decimate the root system and girdle the stems, leading to a dead plant after a few days. The problem is worse when planting into a freshly tilled cover crop. The freshly decomposing organic matter attracts the flies and the larvae move from dead cover crops to transplants. To combat the problem, I only plant early spring crops into a field of winter-killed cowpeas. The cowpeas decompose through the winter and in early spring no fresh organic matter is left to attract and feed cabbage maggots.
With the early crimped cereal rye covered by leaf mulch, I expected cabbage maggots to thrive in the fresh decomposing cereal rye below the leaves, consuming any transplants in the system. To my surprise, I had no cabbage maggot damage in the treatments. Early one morning while observing the trials, I noticed swarms of fungus gnats hovering above the leaf mulch on top of the cereal rye. As the fungus gnats landed on the mulch to lay eggs, a pack of predatory mites would emerge from the mulch and consume the eggs immediately. I’m assuming the predatory mites played a role in controlling the cabbage maggot problem, allowing a massive amount of fresh cereal rye organic matter to be applied in the early spring.
No-till kale planted into cereal rye terminated early by applying leaves after crimping.
Credit: Shawn Jadrnicek
Delaying Cereal Rye Maturity
Another happy accident occurred when I conducted the trials with leaf mulch covering the cereal rye. Every treatment in my plots had a control that was crimped but not covered with leaf mulch. Cereal rye in these areas regrew from the early crimping operation. However, I noticed the cereal rye matured later in these areas. Late maturing cereal rye is useful for late-planted crops in no-till systems. Since crimped cereal rye only prevents weeds for six weeks, it’s important to plant soon after crimping. If you crimp when the cereal rye is mature, then wait two weeks to plant, only four weeks of weed control are left.
With late-planted crops, four weeks of weed control may not be enough to get the cash crops established. Crimping cereal rye to delay maturity provides a solution, but it must be done at the correct time. If done too late, some of the cereal rye will stay down and decompose leaving thin areas in the mulching system. More research needs to be done in this area. However, from my observations it appears that crimping when the cereal rye was two feet in height at the pre-heading stage allows maximum regrowth while still delaying maturity by around two weeks.
Irrigation
Within our intensive cover cropping systems, I’ve seen the organic matter content of the soil increase 0.5 percent every year; it now reads close to 6 percent. I strive to use no-till techniques as much as possible and follow cash crops with cover crops by avoiding double- and triple-cropping systems. Now that we’re adding mulch to the crimped cover crop systems, I expect organic matter contents to climb much faster. I’ve read that for every 1 percent increase in organic matter, the soil can hold up to one inch more water. More water stored in the soil means more opportunities to dry farm or reduce irrigation. In the potato and garlic systems described earlier, I only irrigate at the critical crop development stages. When planting winter squash into crimped cover crops, irrigating a few times after transplanting helps plants establish enough to dry farm during a normal rain year on the East Coast. All other crops are irrigated with drip tape placed on top of the crimped cover crop. Pre-irrigating with the drip tape makes planting by hand much easier if the soil is dry. Transplants are then easily watered in and automatically irrigated with the drip system.
Cover crops rarely provide all the fertility to grow the vegetable crops unless legumes are added. Therefore, with rye only cover crops crimped as a mulch, I add fertilizer to the system. I do this prior to planting or I band the fertilizer beside the plants after transplanting. I’ve successfully used blood meal and cotton seed meal with surface-applied techniques. However, during a dry year, the fertilizer may not wash down into the soil to feed the plants and I’ve observed deficiencies during drought. I believe fertigation systems injecting the fertilizer through the drip tape would be ideal, but I’ve yet to adopt the practice. Another consideration with fertility is the increase in organic matter content over time. Calculations indicate mineralization of the organic matter in our soils is releasing 75 pounds of nitrogen a year. While not all is released during a short cropping period, the organic matter is still delivering a substantial amount of fertility to the crops.
Conclusion
The trials I conducted were not analyzed in a scientific way, just through observations taken during my free time. More research is needed to verify my observations and expand the potential for the techniques. Analyzing wood chip and compost mulch in addition to leaf mulch on top of a wide range of cover crops at different depths and at different times for early crimping and extended weed control would help advance and verify the techniques even more. With all the new organic no-till techniques, I see a future where 75 percent of our crops are grown using no-till techniques — saving us time and money while improving the soil.
