Ricky Baruc and Deb Habib
Orange, Massachusetts Mixed vegetables
Occultation, cardboard and other mulches
I TOLD MY FRIEND JULIA SHANKS, AUTHOR OF THE Farmer’s Office, that I was working on a book about no-till growing methods. She told me about this no-till farm in Orange, Massachusetts, that I should check out called Seeds of Solidarity. Before I even had the chance to contact them, a letter came in the mail from Ricky Baruc, the farmer.
Ricky had been getting Growing for Market magazine, and read the stories we were running about no-till. He had been developing his own no-till system for the past twenty years. The letter had clippings of articles he had written for other publications, asking if I’d like an article about his system.
I called Ricky back and told him I was interested in an article for the magazine (which ran in February 2018), and asked him if I could interview him for this book, which is how I found myself on his farm on a hot summer day in June 2017.
I wanted to talk with Ricky because his method used silage tarps and compost as a mulch like some of the other systems I had seen, but incorporated cardboard as a mulch in a way I hadn’t seen. I realized this was a way to deal with the bane of no-till systems — perennial weeds. Ricky’s method is a way to establish growing beds and build soil, almost anywhere, regardless of whether you have good soil or perennial weeds. Which jives with Seeds of Solidarity’s motto to “grow food everywhere.”
Thirty years previously, Ricky had been farming twenty acres in New York State. “It was organic, but not sustainable both for the use of fossil fuel and high level of personal burnout. I lost my joy of farming and never thought I would go back into it for my livelihood,” said Ricky.
“In the ’80s when I got into farming, the standard was 20–30 acres. Things have changed from when we were looking for farmland. When we were looking back in the day, we wanted river bottomland. Now that’s getting hundred-year floods three years in a row. So now, people are going up in the hills.
“That was the typical scale, and so you would have that equipment. There are still people that want to go that route, but there are so many young people that don’t have access to land and don’t even have interest in the tractors and stuff. They just want to grow food. I wish I knew the numbers, but there have got to be thousands of people. Even people doing it on a small scale, they’re still tilling. You don’t have to.
“It’s about thinking smarter. There are more and more people asking, how do you build this land? How does the farm get richer each year rather than getting depleted? That’s why so many people are going towards reduced tillage.”
When they moved to their current location, Ricky and his wife Deb Habib founded an educational nonprofit, the Seeds of Solidarity Education Center. The emphasis for both of them is the intersection of social justice and food issues, to promote their goal to “awaken the power of youth, schools, and families to Grow Food Everywhere to transform hunger to health, and create resilient lives and communities.”
Spring garlic emerges in well-mulched permanent raised beds.
Credit: Seeds of Solidarity
When they realized the education center would only support one of them full-time, Ricky decided to try farming their new piece of land, despite the fact that people told him it couldn’t be farmed. The farm is on the kind of land deemed “not suitable for agriculture” because it’s too steep, too rocky, and the soils aren’t good enough. When they arrived on the land, there was nothing but a small clearing that had been used to yard logs.
Thinking conventionally in terms of flat expanses you can drive a tractor on wasn’t going to work. Their land couldn’t be farmed like that. But by using occultation and cardboard, Ricky was able to carve fields out and build soil that now grows great crops. His is a good example for someone looking to break in raw or forested land without a lot of machinery.
“How do you grow where the people are? That’s the thing. You’re looking at pieces of land that aren’t suitable for equipment. How do you grow intensively between buildings, whatever the case is? You’ve got to be innovative. We’re flexible,” said Ricky.
No-till opens land up that isn’t good for cultivation to vegetable and flower growing. “Buying good farmland is difficult, because you’re competing with development for that good, flat land, and there’s only so much of it left,” said Ricky.
“The article I’ll write some day will be ‘farming without farmland.’ These methods are also applicable to urban areas, which is critical. If you’re trying to grow food, and you’re thinking you’ve got to buy farmland, you’ve got to buy equipment, or buy a piece of land with a house on it and a barn, who’s going to be able to do it? We want people to get into it, but the lens to see this through, is that there was no land here,” said Ricky. “This was forest.”
“When we came here, I was so burnt out from farming. I had a choice. So I got back to farming on this little land we had.” The adversity of farming on woods and pasture that had been abandoned for years required developing different techniques from what Ricky was used to using.
As we walk around the farm, we visit fields that have been carved out of the woods on the flattest land the property has to offer. Ricky has about two acres of fields, with a half acre here and a quarter acre there.
“For that first field we saw up there, we went by a co-op, loaded up the car with boxes, and we just started putting down cardboard,” said Ricky.
We’re addicted to constantly adding fertilizer, but how come these farmers were farming for thousands of years without fertilizer?
—RICKY BARUC
“That’s the other piece of this, is how do we grow food, without [prime] land, with minimal labor, without getting so stressed out? On so many farms when they get it tilled the weeds go crazy. The silage tarps are great. Basically, when we got on the land here, there was no land here. These fields were used around the Civil War,” said Ricky gesturing to the fields closest to the road, “but down [by the house] there was no land.
“We had to build everything. I had no land to do cover crops, now I have enough land and the silage tarps allow me to get clear land to put in cover crops. Now the mix is, you’ve got the silage tarps, you got the cover crops, I got rye and vetch growing in a whole bunch of places, and my favorite is the cardboard,” said Ricky as I followed him to his lower fields. “Cover crops, silage tarps, permanent beds, and then the cardboard. That’s what I’m after. I’ll show you more about that down below.
Corn was planted into compost on top of cardboard. Ricky is digging down through the compost to find the cardboard layer.
Credit: Andrew Mefferd
“Basically, we’re talking no land, no equipment, minimal labor, so how are you going to farm? You can’t find good labor around here. This way I can basically farm alone. I had apprentices. Some years it was great, some years miserable. What I realized is, when I was working by myself, it’s like, ‘I’m happy right now. Huh.’ You end up managing the group and you’re never satisfied with their work, right?”
“So where did the inspiration and ideas come from? Tell me about the process where you came to this system,” I asked.
“In Montague, a few towns over, I had quite a big market garden. I knew about black plastic. I assumed the black plastic would kill sod. I don’t even know how it came to me, but I just said, ‘What about cardboard?’ Sometimes the best idea is one you don’t mull over, it just happens. So I just went for it. And when we moved here, I needed to open up land. I just started taking out cardboard. I didn’t know, there was no guarantee,” said Ricky.
“The silage tarp was because of the lamb’s quarters disaster. That became my second tool. And the biggest thing was that I had absolutely no mechanical aptitude. I just have no interest in spending any of my time doing that.”
Ricky’s enthusiasm for the system is visible as we walk around the farm. We walk past broccoli, kale, beets, onions, greens, chard, all kinds of crops planted in permanent beds.
“That’s the thing I’m interested in is that — we don’t know what’s going on in the soil, and there’s a lot going on. If I can inspire people that it’s not only better for not releasing CO2, there are so many benefits to not tilling. I think that’s going to be the sales pitch,” said Ricky.
“Basically, my whole thing is if you’re going to do transplants, use cardboard. If you need to plant cover crops or scatter sow seeds or direct sow, use the silage tarps. That’s how I distinguish the [methods],” said Ricky.
“Then you can do all your transplants into the cardboard. You put your cover crop or scatter sow seeds where the silage tarps were. Then as soon as you can when you have bare ground, put in cover crops. You have cardboard, silage tarps, cover crops. Those are the three things.
“Stress is only going to increase with this crazy weather. You want to figure out how to minimize the stress not knowing if there’s going to be a drought, or heavy rains, you just don’t know. It’s modern-day growing. How do we grow in this crazy erratic climate? I think that’s the beauty of both methods, is they’re keeping the moisture in, but also we found in years we had too much moisture, it doesn’t allow too much moisture to saturate the cardboard, as well as the silage tarps. It gets a lot of stuff in, but it doesn’t let the moisture leave. It keeps a steady state of moisture, which is good.”
We find lots of worms in the compost and cardboard.
Credit: Andrew Mefferd
The most concise explanation of Ricky’s cardboard mulch method appeared in the article he wrote for Growing for Market in February 2018. So here it is, followed by the discussion we had while looking at it on his farm in 2017:
Cardboard is my way to open up new land, my weed control, moisture control, and worm food that results in nutrient rich castings — my primary fertilizer. One full pickup truck load of large sheets of cardboard from furniture, bike, or appliance stores will cover an area 35 by 100 feet.
Let’s say it is early spring, even with a bit of snow still on the ground. I open large cardboard boxes with a box cutter so that it is one layer thick. Then I lay the sheets on my field, ensuring that there is at least a three-inch overlap between pieces. You can remove any plastic tape now, but it is also fun to do so when that is the only thing left!
I have my covering material nearby, be it mulch hay or inexpensive manure — partially decomposed horse manure is fine for this purpose. The mulch is to hold the cardboard in place and keep it moist. It is a good idea to cover as you go, so the wind doesn’t pick up the pieces. I lay cardboard right over my permanent raised beds; it will conform to their shape once it gets wet and begins to soften. If you know your soil is not very fertile, put an inch or two of finished compost or manure down before you lay the cardboard down to increase fertility as well as speed the decomposition of the cardboard with the infusion of worms and microbes.
The soil that he has built is so loose and friable Ricky can easily dig with his hand up to his elbow.
Credit: Andrew Mefferd
Cardboard is a great method to use for transplants. In as little as two to three weeks, the cardboard will be soft enough to dibble through for planting seedlings. I grow a lot of bunching greens like kale and collards, and also use this technique with success for garlic, corn, and squash. At the same time, there is no rush — the cardboard will be your mulch, keeping weeds at bay and the life in the soil happy until you are ready to plant. This is also a great technique for fields that you wish to leave fallow to replenish; once the cardboard is fully decomposed months later, you can decide to cover crop or add more cardboard.
In the areas where I have been using cardboard for at least five years, the growing beds have become so established and rich that I no longer need additional compost and have never added lime; the cardboard and subsequent worm, microbial and mycorrhizal activity balances the soil and feeds the plants. I call it the ‘no-till self-sustaining cardboard method.’ This is huge in regards to the cost of acquiring compost or other fertilizers, as well as labor time and cost.
A common question that people ask is whether cardboard is safe. Our experience is that the use of plain brown corrugated cardboard (the hide glue used is high in protein, which also attracts the worms) promotes incredible life in the soil. A telling year of the moisture moderating benefits of cardboard came in 2016 during that incredible season of drought. Two inches below the cardboard and without irrigation, the soil was moist and worms were active, and above, the crops were fine.” [Author’s note: Some organic certifiers prohibit cardboard that has ink in colors other than black. As always, check with your certifier if you are certified organic.]
The soil underneath the cardboard is rich, black, and loose.
Credit: Andrew Mefferd
“The cardboard is the key for the worm population,” Ricky explains. “It really hit me last year. During the drought I was able to go under the cardboard and the soil under there was moist and full of worms. You look at things politically, spiritually, and environmentally. The political way to look at it is tilling is like this culture. It’s like we’re going to go in there even though this incredible relationship in the soil has developed, we’re going to go in there and just [destroy everything].”
“It’s a destructive release. You do release fertility but at the expense of all those relationships,” I said.
“There’s an initial rush, that’s what the farmers have liked, but it’s burning out the savings account. Every time you till you’re taking savings out of the account. People like Elaine Ingham and Michael Phillips, they’re all writing about this stuff. That’s why this no-till book is critical at this time. Once people figure out what’s going on in the soil, they’re not going to want to mess with living soil. How do you do that? How do we grow food in a way that’s minimally disturbing?” said Ricky.
“Remember, there was no soil here, so this has been built up over the years. We just went in there, covered it with cardboard. Then we got the cheap compost, just to weigh it down, and for some nutrients. Let that cardboard get wet and I dibbled through it and so the beauty of it is all that labor saved, plus weed control, moisture control. And then that cardboard is the fertilizer, so ultimately what I’m after is the Farmers of Forty Centuries stuff,” said Ricky. [Author’s note: Farmers of Forty Centuries is a book that looks at traditional farming methods and how fertility was maintained over long periods of time; see the Resources section.]
The residue from the previous crop is still visible, though it is dry and there are no weeds.
Credit: Andrew Mefferd
“We’re addicted to constantly adding fertilizer, but how come these farmers were farming for thousands of years without fertilizer? I think we’re used to adding this amount of fertilizer based on a soil that’s not very alive. Can you get a real living soil by not tilling and minimal inputs? That’s what I’m most interested in, with the input of cardboard. So it’s multifunction as it covers the land so I don’t have to till, it’s the weed control, it’s the moisture control, and it’s the fertilizer. That’s what I’m after. I’m really going after minimal inputs on not very good land,” said Ricky.
“The corn looks pretty good. We’ll see what this looks like underneath. This is the stuff that I just love doing,” said Ricky, kneeling down and pulling back the mulch at the base of a bed of corn.
“It’s been dry, but I just love the moisture. I think in terms of growing, that plants are like humans. They want it moderated. They don’t like it too hot, too wet. That’s the nice thing about the mulch. It keeps it pretty steady. This is what we’re after, look at that right there,” Ricky says as he scoops out soil that is moist, crumbly, and filled with worms.
“What we tell people is, cardboard is the perfect worm food. Worm poop is the perfect plant food. This is from Amy Stewart’s book [The Earth Moved: On the Remarkable Achievements of Earthworms]. One acre of land per year with heavy worm populations will produce 150 tons of worm castings. You can see why. They go year-round. The only time worms are in jeopardy is if you get an early frost. One nice thing about the cardboard is it moderates the soil so [you’re protected from extremes]. You can see they were really hanging out where it was the most moist,” said Ricky.
“Oh, yeah,” I say, “worms are all over the place. This is all built soil?”
“Yes. So rather than incorporating in the soil by tilling it, there is this design to deal with it, just like the forest floor. [Organic matter goes on top,] microorganisms will come up and break it down,” said Ricky.
“That’s beautiful soil,” I said as Ricky dug down through the earth with his hands. The soil was dark and crumbly like potting soil.
Meanwhile, Ricky continued making the hole bigger. “Hey, look at that. That’s the base. When we brought in sand to level, that’s where it started. You can see that’s sand,” said Ricky, having scooped a foot or more deep down to a sandy layer with his hands. In the greenhouses there is as much as two feet of soil on top of the sand.
“There was no soil. What we tell people is, you don’t have to till it. [This amount of topsoil is what you get] twenty years later. Well, maybe not quite that many, but you get the idea.
“The cardboard I think is really a winner. As you can see, [the earthworms are] doing the work. Cardboard is my favorite for transplanting into. Hands down, it’s really building soil. Silage tarps are my second favorite because they allow me not to have to incorporate the [residue], whatever it is, weeds or cover crops. Or to have to hoe and take it away, so it keeps the organic matter right there. I wonder to myself, all of our cover crops once you till them in, what detriment is that, the tilling part?” said Ricky.
We look at an area with a dense stand of winter rye on it.
“This was a corn crop that was in cardboard. And the nice thing about the cardboard, it really hangs in there long enough [for long-term weed suppression]. There really wasn’t much left. We just had to pull out the corn stubble, very minimal weeding, and I was able to rake and then just put the rye in.”
“So this rye was planted into a layer of compost that was on top of cardboard from the previous corn crop?” I asked.
“Well, the cardboard breaks down pretty quickly. There was cardboard, compost, corn stalks. And so this spring, I got rid of the corn stubble and just planted right into it. Yes, so no manipulation,” said Ricky.
In response to my question, Ricky started digging around in the soil under the rye with his hands. After getting down through the soil, he found the remains of the cardboard.
“Look at this. There’s a little cardboard left, which is interesting. The corn stubble is still here as you can see,” said Ricky.
We walked into a hoophouse that had a spinach crop in it.
“This is a good little example here. A spinach crop, did great. Now the crop is done. What is a person to do? You could get your tiller in here and till the whole thing. I come in here and cover it with cardboard. You could use silage tarps, but in this case I’m going to do cardboard. A silage tarp is perfect when you’re going to direct sow. Cardboard is perfect for transplanting into. That’s really the distinction. Because in the greenhouses I plant mainly greens that I scatter sow, like Bryan O’Hara (see interview p. 305). I want bare ground. I’ll put compost on top and then scatter sow seeds,” said Ricky.
In hoophouse tomatoes planted through cardboard, the root zone stays moist even though it is hot and dry.
Credit: Andrew Mefferd
“I knew in here I was going to transplant. I came in here real quick. Imagine the amount of time it would take me to till in that spinach, wait for [it to break down], and then who knows what is happening to the soil because we don’t really understand soil at this point. Instead, I put down the cardboard that day or a couple days later, whatever, cut out the holes and put compost in the holes and planted tomatoes into it. Then all that organic matter is dying and I haven’t disturbed anything, with minimal weeding.
“Thinking about the farmer, the crop’s done, and you’ve got all this other stuff happening. Now I got to deal with this stuff. This way I can just throw the cardboard down. It’s saving me lots of labor. [If you tilled,] you’re still going to have to either make beds again or weed. This way it’s multipurpose.”
Ricky started digging around under the cardboard the tomatoes were transplanted into. He showed me the layer below the cardboard where the spinach was. The previous crop of spinach is all gone.
“Here you go. It was all spring spinach. Now there is no sign of spinach. That’s just magical,” said Ricky.
“And how much time passed between when you put the cardboard on and when you transplanted your tomatoes?” I asked.
“I’d be doing it that day. Yeah, that’s the beauty of it. With tilling, farmers love that tilling because it releases all the fertility, right? You’re getting that with this thing, too, because all [the residue from the previous crop is] breaking down and feeding [the next crop],” said Ricky.
Here’s Ricky’s description of how he uses silage tarps, also from the February 2018 Growing for Market:
When I want bare ground to sow cover crops or scatter-sow seed for salad greens, such as in our hoophouses, I use silage covers. I use large silage covers to create darkness to rapidly turn fresh biomass into mulch and leave bare soil below.
Seedlings thrive in cardboard mulch, but to sow seeds directly without tilling, silage covers (also called bunker or panda covers) are a great method. These are much thicker and more durable than regular black plastic, last many years, and can be easily moved around a farm or garden as needed. Weeds or cover crops under the tarp die and become mulch that is transplanted into, or raked off and composted in the paths.
Two months after placing a silage cover down, all the weeds have become a layer of broken-down biomass that I can transplant right into without needing to till or remake raised beds, an enormous labor saver! Weed seeds germinate in the warm, moist conditions generated by the tarp, but are then killed by the absence of light.
Garlic grows weed free in heavily mulched beds.
Credit: Andrew Mefferd
Once tillage stops, the cycle of bringing weed seeds up from below is broken. The beauty of silage covers is that the previous crop becomes a carpet of biomass that will create a barrier to many of the un-germinated weed seeds still in the bed. And as long as I add clean compost above the biomass into which I then plant, I have minimal weed issues.
I also use the silage covers in our four, 30-×-96-foot hoophouses, where we do “cut and come again” greens production in succession through the season. I place the covers over the beds of greens after they have provided multiple harvests but are no longer marketable. The heat of the hoophouse really speeds up the breakdown of the crop residue below. All the green matter becomes brown and I cover this biomass with a half-inch layer of compost and sow the next crop of salad greens right into that.
Or, I can easily rake off the broken-down biomass whereas before I had to hoe the previous crop and remove it. I was somewhat concerned as to whether the silage covers would harm the life in the soil. So one day I looked under all of the dead biomass of the previous greens crop, after two weeks under a silage cover. The biomass was moist and the soil below it was cool, creating a perfect environment for worms to do what they love: eat, reproduce and poop, with a wonderful new layer of castings produced.
Silage tarps give me breathing room. Once the season is going, there are so many pieces of farming that demand attention. To be able to cover a field once crops have been harvested, wait until the plant material breaks down, then decide how to best use an area eases my mind, versus looking around, seeing weeds and stressing.
I have also found that silage tarps are a great way to incorporate cover crops into the soil, rather than tilling them in. This technique would be helpful to those who do use machinery during a wet spring, when you can’t get on the land to till in an overwintered cover crop. Additionally, land that is covered with a silage tarp in early spring will help the land to warm up more quickly for planting, as well as activating the soil to nourish your plants to come.
Besides tremendous soil building and other environmentally beneficial aspects, no-till helps with the stress factor of farming. There can be great stress associated with the feeling of “I’ve got to get these fields tilled now,” and then once tilled ‘I’ve got to get those plants or seeds in the ground before the weeds get a head start.’ When I see all of our farmland planted or mulched in cardboard, regenerating with silage tarps, or in cover crops, I feel all is well and cared for.
For those out there who would like to use their hands more, and machinery less or not at all, decrease labor due to fewer weeds, reduce fertilizer inputs and eliminate release of CO2 from tilling, these techniques may be for you. It is heartening to see a movement towards mimicking nature, as evidenced by the many farming articles and conference presentations that focus on revering the life in the soil. As farmers, it is critical to keep ourselves healthy for the long haul, and leave land better than it was when we started working it. After farming for thirty years, the practices I’ve developed, arrived at, continue to explore, and love to share nourish me as a human being by creating an honoring relationship with the soil, one that enhances life.
Having seen mulches applied to suppress weeds in no-till systems on other farms, I asked Ricky how he came up with the method. Like so many inventions, Ricky’s came from dealing with adversity.
“We had this great chicken compost we were using for years. And then a bunch of years back, I was planting three 100-foot beds a week. And two weeks into it, it was all just lamb’s quarters. So somehow, either here or at the farm, lamb’s quarters inoculated all the compost,” said Ricky. “The point is, how do I get rid of them? I found that FarmTek had this heavy-duty silage tarp. So I used that to kill all of the weeds.” “Then I went to this farmer [meeting for] reduced tillage, I brought this concept of silage tarps. And they were laughing at me, I kid you not. A guy at the meeting said he Googled it, and ‘There’s no word occultation.’ They just thought I was totally nuts.
“But Cornell is doing research with these silage tarps, and what’s happening with them, is that it’s heating up the soil in the spring, which is really critical for getting the nutrients available. The other really cool thing about the silage tarps is, cover crops are great as you know, but if you have a wet spring, you can’t get on the land, and then you have to till in this cover crop, and you have to wait a period of time [for the cover crop to break down in the soil. By then] the season’s basically over.”
“Yeah, in the northeast US it is,” I said.
“These days you’re almost guaranteed a wet spring. At least with permanent beds, you don’t have to be stressed that you can’t get the tractor on. And if you do have cover crops, using these silage tarps at least you can get the cover crops out of the way in the springtime without manipulating the soil. There’s no reason you have to manipulate the soil with the tarps,” said Ricky.
We look at a field that developed a weed problem after the previous crop was done. “I didn’t have enough silage tarps and within a month it was up like this with weeds and stuff. I kid you not, two-foot-plus weeds. And I did a workshop here, it was a great demo to say, look. The beauty of this thing [is that the tarps killed the overgrown weeds without tillage]. Now I just pull the tarp back and I can plant bed by bed, so I’m not stressing out. Say you have a garlic crop, and then the garlic crop comes out, there’s going to be weeds. You cover it, you let it sit, and that’s where the whole Jean-Martin Fortier thing is. If you just time things right [you can let the tarps sit and kill the weeds while you do other things],” said Ricky.
Ricky was not the first no-tiller I had talked with to bring up Jean-Martin Fortier. In fact, many of them that used tarps to kill weeds referenced Jean-Martin, and as far as I can tell he’s the reason growers in North America are calling tarping “occultation”; I certainly hadn’t heard the term until I read his book. To see what everyone is talking about, read the sidebars quoted from Jean-Martin’s book The Market Gardener.
From Jean-Martin Fortier, The Market Gardener, p. 50.
Tarps and Pre-Crop
Ground Cover
One of the most important discoveries we made throughout the years has been that of relying on soil-covering tarps to smother crop debris when preparing new ground.
Until then, our only way of clearing the remains of finished crops and established weeds was to either till them into the ground with multiple passes of the rototiller or manually remove them. As we started to move away from relying on the tiller, we often favored hand picking out weeds and residues, rationalizing this time-consuming activity by telling ourselves that all this organic material we were bringing to the compost pile would eventually become great soil building material. This way of working was labor-intensive and time-consuming, and our beds were never really cleaned of the smaller weeds.
Permanent beds under occultation in a garlic field.
Credit: Andrew Mefferd
Then one midsummer’s day, I bought a big black UV-treated polyethylene tarp to break open new ground where we planned to plant berries. My idea was to dry it out before putting it away in the shed. As it happened, it stayed there for three weeks, and when we finally moved it away, it struck us — the tarps had killed all crop residues and weeds, leaving us with a very clean bed surface to work on. We had stumbled onto a technique that was highly effective. Ever since, we have used tarps to cover the ground as a complement to our minimal tillage system.
Every time a harvest is done with, we immediately cover it. Depending on what crop is next in line on the schedule, the tarp will remain on the bed for anywhere between two to four weeks, leaving our minds worry-free. Passively, we are preparing the soil for the next seeding while also weeding it just like a false seedbed would.
Over time we have consistently noticed a difference in weed pressure on beds that have been covered compared with others that have not. The explanation is simple: the tarp creates warm moist conditions in which weed seeds germinate, but the young weeds are then killed by the absence of light. Looking into this we found out that French growers were widely using this technique (called occultation) to diminish, or even eliminate, weed infestations in their fields.
From Jean-Martin Fortier, The Market Gardener, p. 104–05
Weeding with Tarps
The main factor in keeping a garden weed-free is how much space is to be kept under control. Our 10 plots have a total area of 1½ acres, and if we had to cultivate the whole garden every week, I doubt we would manage. This is where the opaque UV-treated tarps come in handy. Not only are they useful for smothering weedy ground in preparing the soil before planting, but when covering unused beds, the tarp limits the surface area on which weeds can establish themselves. Even more interestingly we have also observed that black tarps do an especially good job of diminishing weed pressure on subsequent crops....
We have been using 6 mm black silage tarps in the garden for almost a decade now and I can say without hesitation that their usefulness is one of the reasons behind the overall success of our operation. This passive and efficient practice takes care of part of the weeding chores while we are getting work done elsewhere in the garden. Besides being a petroleum product, the only difficulty we face using these bulky tarps is that they are heavy to move around. Our solution to this has been to buy more of them every year, with the intended goal of having one for every plot, thus eliminating the need to carry them from one garden to another. This minor challenge aside, the overall advantages far outweigh the drawbacks.
“With the silage tarp, what kind of time frame are we talking about for leaving it down?” I asked.
“In the greenhouse, we’re talking three weeks; outside, a month, month and a half. The longer the better, for sure. In this one greenhouse you’ll see we had early greens. When they were done, I just let them keep growing because I knew I didn’t have to freak out. Because in the old days I’d have to scythe them, hoe them, haul [the biomass] out. Talk about labor, right? Now basically all I have to do is scythe, cover, done. I can let them grow as tall as I want. I knew I wasn’t going to replant there for a while,” said Ricky.
“In the greenhouse, I was concerned, was I killing the worm population? What’s happening is all that organic matter is on the top, the worms are happy in the moisture underneath and so they’re not being bothered.”
We walk over to another one of Ricky’s greenhouses. A silage tarp is covering the whole growing area, black side up. Ricky pulls up a corner to reveal the remains of a tall crop, which is flat and light green. It reminds me of hay before it is baled.
“Is this the leftover crop or is this a cover crop?” I asked.
“Good question. This was my first round of spring greens, but they’ve all gone to seed. I wanted to bring bees here, so I let them flower. Three-foot-high plants all going to seed big time,” said Ricky.
“This was all salad mix, spinach, arugula, lettuce heads. I started early this year, so this was my first crop. Now I’ll be coming back in here and getting the second crop. This is beautiful. I have enough space so I didn’t need this immediately. This is the rotation, in a sense. Look, the moisture is still there. It didn’t dry out, right?”
Occultation acts as a placeholder so unplanted beds don’t grow weeds in this hoophouse.
Credit: Andrew Mefferd
“That’s a good point. If it were uncovered it would be really dry right now,” I said. Even though the remains of the crop aren’t succulent anymore, the soil under the tarp is still moist.
“I was smart enough to remember to write down when we put this silage tarp down. It went down on May 30, what’s today?” Ricky asked.
“June 13,” I replied.
“All right, this is 14 days later. May 30, 2017, silage tarp down. Two weeks later, my choice is this. I could put compost on and either plant greens or transplant into it. I don’t usually in the greenhouses, but I could put cardboard down. Or look at this, look how easy it is to do this,” said Ricky.
Time is saved with the silage tarp turning weeds into biomass; a field is ready to replant without having to till or remake raised beds.
Credit: Seeds of Solidarity
While we’re talking, Ricky is raking the dried plant residue off of the bed. Even though it flowered and grew a lot more biomass than most greens crops ever do, after two weeks under the silage tarp inside the hoophouse, the remnants of the crop are easy to remove from the top of the bed.
“Look how easy that is,” he says. “This whole thing, [the bolted greens] were maybe three feet high. Imagine what I used to do before. Because back in the day, I was cranking the greens out to lots of restaurants, so I had to really time it all carefully. I’d come in here and scythe and hoe and I’d bring it over there [to the compost pile]. That was a lot of labor.
“Look how easy this comes out. You can either rake this off if you need it clear. Most likely at this point I would just put compost right over it. What I’m trying to figure out is how to do things with the least amount of labor. Because why move it away if it’s going to make organic matter here?”
Under the silage tarp, under the partially decomposed greens crop that had gone to flower, the soil is still moist and friable. Seeing this with Ricky, I realized that he basically turned his cash crop (salad greens) into a cover crop (by letting it go to flower, something most growers would avoid at all costs), both giving the bees a source of nectar early in the season and giving himself a cover crop without having to till or plant anything else beyond the main crop.
“So I put this tarp down. Here we are two weeks later. Now I can just basically unroll and start planting,” said Ricky.
“I put a temperature probe outside in the spring under the tarp. It was five or ten degrees warmer [than the uncovered soil temperature]. Actually, under the cardboard it was warmer than the normal soil too. Because sometimes you think cardboard is going to keep the soil cooler, but it wasn’t cooler than the normal soil. Cardboard was warmer than the normal soil and the silage tarp was quite a bit warmer. It’s beneficial in the spring for the nutrient availability, but they’re finding out it’s even better in the fall too.”
No-till garlic.
Credit: Andrew Mefferd
“I love this stuff that you’re showing me. I love the fact that you can just go in and put the tarp down to terminate the previous crop without tilling or taking all that organic matter out of there,” I said.
“Exactly, but even once you’ve tilled, then you’re still stressed about what to do now. The ground is tilled and now you’re even more stressed,” said Ricky.
“You got to bed back up again. Re-fertilize. I don’t know which is worse, but you know what I’m getting at. Either way you’re stressed to get it tilled and then you’re stressed once it’s tilled. We take something we love, turn it into a business, and then we hate it because it stresses us out,” said Ricky.
“Did you scythe the bolted spinach or did you just put the cardboard down right on top of it?” I asked.
“You could just knock it down if you didn’t want to scythe it, but that stuff was really tall. There was so much of it so I scythed it,” said Ricky.
Ricky does workshops on his farm demonstrating his methods. “It’s so interesting when people come to the workshops, I love to hear what they say first because that’s what really hit them, right? I ran into a few people from a workshop we had done some time later. What got people so interested is that we harvested the crop, and we replanted it the same day. Not to say that’s the end all, but the point is that you could do that, versus getting all this equipment out and stuff. The whole tilling thing, I think, is passé,” said Ricky.
We peek under another silage tarp.
“Here’s a perfect example. Once again the silage tarps; I just pull it back, it’s relatively clean. What’s actually there is some residual garlic, so I have to hoe that out, but it’s not too bad. It definitely kills anything. This is a good demo. I’ve never really done it before. This was planted in October,” said Ricky.
“Look at the worms, look at that. There was cardboard there. Now the question is, where the heck is the cardboard? We’re talking November, December, January, February, March, April, May, June, say seven months and the cardboard is gone. Where did it go? What sort of fertility did it give? It’s not much of a weed barrier anymore as you can see, but the other thing I like about the silage tarps and this stuff is that if the weeds never get to see the sun, they won’t grow. If I have a silage tarp down, I’ll pull it off, immediately get compost on, plant or mulch or cardboard for that matter, it never sees the sun so the weeds are much better.”
Salad greens are planted intensively in hoophouses; previous crops are composted in place with silage tarps speeding the process.
Credit: Andrew Mefferd
“For people who are going into this, is that your recommendation? Throw the cardboard down, take soil out of the planting hole, and put in compost? Or if you’re going to break in a new space, would you amend the area first? Is some compost right in the planting hole going to carry the plant through the season, and then you’re going to build the soil up over time?” I asked.
“So these are the options. One, if you’re going to plant, say, tomatoes, eggplant, peppers, bigger squashes, do what I mentioned. Put down cardboard, take the soil out of the planting hole, [fill the planting hole with] compost, and hopefully that lawn has some soil. That’s your first season,” said Ricky.
“Your other option is to put down a layer of good compost, cardboard on top of it, make it wet and do transplants like kale, collards, lettuce, stuff you can plant close together. Then I would do that method.
“The third method is, especially if you have contaminated soil, put maybe wood chips down and make a barrier. You can put cardboard down, good compost, and then scatter sow greens seeds, because the greens don’t need much soil. Those are the three methods. Tomatoes, peppers, eggplant, big plants, you can plant maybe two, two-and-a-half feet apart, through the hole. Things you can plant 18 inches apart are the kales, lettuce, [bunching greens]. It always helps to have either grass clippings, hay, wood chips or something on top of the cardboard.”
“To keep it from blowing away?” I asked.
“Yeah, or you could use [low-grade] compost just to hold it down. The thing about the cardboard, which is so great, is it’s guaranteed weed control and you don’t have to keep watering. The cardboard has got to be covered because otherwise it will dry out. You always want to keep something on top of it. Once it’s covered, it’s very mucousy, it’s got hide glue in it, it’s high in protein. That’s what the worms are attracted to. Once they start messing with it, you’re good,” said Ricky.
“For the fourth technique I would go with the silage tarp. You can get any size silage tarp up to 80 by 100, which is huge.
A former logged area is transformed into a productive small farm landscape using cardboard and other no-till methods.
Credit: Andrew Mefferd
“There are always going to be naysayers, but I think what’s cool about a book, because it does not exist, and [the no-till methods], they’re all coming from different angles. There’s so many different ways of doing it. It’s not like it’s got to be this one way. People will get to relate to different farms and their personal stories. It’s going to be so cool to have a book so people have access to the people doing no-till. Then it will keep growing.
“I think all those pieces, labor, CO2 emissions, go into it. But it’s the stress factor. We need young people to go into it. Because if nothing else it’s about feeding ourselves healthy food, connecting back to the Earth. That’s basically in all the spiritual books what it’s all about. We’ve got to reconnect. We’re interrelated, coming from the heart. If we’re going to survive the next so many years, it’s not just techniques; it’s not just making a living. It’s about reconnecting.”
After a delicious lunch of tortillas and farm-grown salad, I helped Ricky and his crew pull a large silage tarp down the road onto the next plot. I said my goodbyes, turned off the recording and turned to get in my car when Ricky left me with one last thought: “If you can do it here you can do it anywhere!”
