“I think this is what hooks one to gardening: it is the closest one can come to being present at creation.”
— Phyllis Theroux, author
Compost is most useful when it has completely finished maturing, but it can also be used when it is slightly underdone. Compost that is not quite ready for use may still have some undigested bits of plant, fruit, or vegetable matter in it. The bits may or may not be recognizable as food. It will not have the characteristic look and may not have the clean, rich smell of finished compost. It may still be warm to the touch because the microorganisms are still living and working in it. It should be mostly dark brown in color.
When you use it depends on what you are using it for and where and how you plan to use it. Compost should be sifted before use to remove any large pieces, because these pieces are not finished breaking down. This sifting process is described later in this chapter. Return these pieces to the compost to finish decaying. Compost materials that have not fully decayed will finish composting in or on the ground, but if they are dug or tilled into the soil, they can use up available nitrogen as they decompose. This will rob nitrogen from your plants, and so it is better to let the compost mature fully or to use unfinished compost only as mulch. If unfinished compost is used as mulch, it will leach nutrients slowly into the soil, giving your plants a constant supply of nutrients over a period of weeks rather than one big boost of energy.
Finished compost should be used as soon as possible because letting it sit will cause it to leach nutrients back into the air and soil. The fibers and aggregate clumps will break down into smaller and smaller pieces, and soon it will lose its soil-amending qualities. It should sit for no longer than six months before use. It is better to use compost that is not quite mature than to leave it sitting around for too long.
Where to Use Compost
Compost can be used everywhere in the garden. It adds beneficial microbes to the soil, retains water, and suppresses weeds and many plant diseases. Compost works best if you apply it after a rain, or after watering the garden, is not, or lawn. The following are some ways and places you can use your compost:
• To feed new lawns, spread a layer of compost ¼-inch deep over the grass seed.
• To dress bare spots on lawns, spread a dense layer of compost on the bare spots.
• Use compost as mulch in vegetable and flower gardens. Make sure to use only mature, sifted compost around new plantings to avoid damage from undigested organic material and weed seeds.
• Use sifted compost as a seed starter in a one-to-one combination with either leaf mold or worm castings.
• Use sifted compost as bedding in a worm bin by mixing it one-to-one with damp, shredded newspaper.
• Use a combination of one-third compost and two-thirds potting soil in flowerpots and containers. Soil is necessary to give the plant roots something to grip, so do not plant them in 100-percent compost.
• Use compost on sandy or clay soils to amend them by retaining moisture, improving drainage, and introducing beneficial bacteria.
• Use compost around trees of any age to suppress weeds, prevent erosion, and protect from drought. Spread a 2- to 4-inch layer out to the drip line of the tree twice a year. (The drip line is an imaginary circle around the tree just under the tips of the branches.)
Healthy Soil Leads to Healthy Produce
Decades of commercial farming with the use of artificially produced fertilizers have left many soils depleted of nutrients. A University of Illinois study looked at soil samples collected over the past 100 years from the Morrow Plots — the oldest experimental field in the United States. They discovered that yields were 20 percent lower in the portion of the field that received the most fertilization with synthetic nitrogen fertilizers. They analyzed soil samples and found that there had been an average decrease in soil organic carbon of 4.9 tons per acre. Over-fertilization with artificial nitrogen fertilizers leads to a loss of carbon in the soil, which in turn decreases soil’s ability to store water. While synthetic fertilizer is important, the scientists pointed out that “excessive application rates cut profits and are bad for soils and the environment.”
If there are fewer nutrients in the soil, there will be fewer nutrients in the fruits and vegetables we grow and, therefore, in our diets. Studies conducted on commercially grown produce in the United States, United Kingdom, and Canada have all shown marked decreases in vitamins and minerals in common foods grown since 1951.
Information in the table below was taken from data gathered and analyzed in 2002 for CTV News, a Canadian news network. It shows the percentage change in common vitamins and nutrients in selected produce grown between 1951 and 1999. Negative changes are noted, and, as you can see, with the single exception of corn, all of these common foods now have much smaller quantities of several important nutrients than they did just a few decades ago.
Because compost contains a wider variety of nutrients than commercial fertilizers, and because it has soil-amending qualities that help oxygen and water get to plant roots, it does a great job at making your vegetable plants more vigorous and healthy. If you want to feed yourself and your family a healthy diet, growing your own produce and feeding it with compost will go a long way toward ensuring your family receives all the vitamins and minerals they need.
Preparing Compost for Use
Before you can use your compost, you will need to transform it into a usable state. If you are just mulching with it, you can spread the compost directly from the compost pile once it has finished decaying. But if you plan to use it in containers, flowerpots, as a seed starter, or around new plantings, you will have to sift it. Instructions for making a compost sifter are included below. You may also want to make compost tea to water both indoor and outdoor plants. Instructions for making compost tea are included later in this chapter. Before you use compost, you may want to check your soil condition. Determining the soil pH and learning what minerals it lacks will help you decide where to use compost to its best advantage.
Testing for pH levels
Finished compost should have a neutral pH, meaning it is neither acidic nor alkaline. The pH scale ranges from 1 — very acidic — to 14 — very alkaline — so neutral soil or compost will have a pH level of 7. Most plants flourish best in the range of 6 to 7 on the pH scale because it is at this range that most of the important nutrients, including nitrogen, phosphorus, and potassium, are available to the plant. For this reason, compost can be used everywhere in your garden without harming plants. Also, because it is neutral, it will not burn your plants the way fresh manure or synthetic fertilizers might.
If you have used an overabundance of acidic materials, such as pine needles, pine sawdust, or oak leaves in your compost, you should let the compost mature completely before using it. As leaves and evergreen needles decompose, their pH level rises, making these plant items less acidic and almost neutral.
You should do a pH test of the soil in your lawn or garden to determine what kind of amendments it may need. You may want to check each flower bed or garden plot individually because pH can vary widely even in the same area. Knowing the pH of the soil in different planting beds, garden areas, and containers will help you customize the soil environment to the needs of your plants and will result in stronger, healthier vegetation.
Whether your garden soil is acidic or alkaline, adding compost will help bring it back into neutral territory. This is desirable for most plants, but some, such as azaleas, rhododendrons, and hydrangeas, love acidic soil. For plants like these, you may want to amend the compost-enriched soil with extra helpings of acidic materials such as pine needles. Hydrangeas, in particular, are very responsive to soil pH and the color of the flowers varies with the pH. In a low pH soil of about 5 to 5.5, the flowers will be blue. A pH level of 6 or higher will produce pink flowers. To find out what kind of soil is best for your plants, check with a local greenhouse or your nearest university extension office.
To test your soil pH, you can use a simple kit from a garden store or local extension service. These kits range in price from about $1 for a single-use kit, to hundreds of dollars for professional test kits. A mid-range kit of $10 or $20 is adequate for almost any household garden. Most kits include enough supplies to test dozens of samples, so you can test individual flower beds or vegetable plots easily. The mid-range and high-end kits will also tell you the levels of nitrogen, phosphorus, and potassium in the soil, so you can amend if necessary. Truly dedicated gardeners might want to purchase a pH meter. This device has a probe that you insert into damp earth, and after a minute, it gives you the pH of that particular area. These devices cost about $25 and are available at most garden supply stores or online.
Testing is easy, and instructions will come with any test kit you purchase. In general, you should collect a soil sample from 2 to 3 inches below the surface. Mix the soil with the specified amount of water and shake the mixture in the container provided. Add the chemical that came with the kit, wait the required length of time, then read the color-coded results on the container to see your pH level. Sometimes you will discover that your soil pH is just fine. If not, the test kit should contain a chart that will tell you how much lime (in the form of ground limestone) to add to make the soil more alkaline, or how much sulphur to add to make it more acidic. You can purchase either of these materials at a gardening supply store or online.
Keep in mind that lime does not work immediately. It can take a few months for the lime to fully integrate with the soil. Also, applying lime while plants are growing can be harmful to the plants, so it is best to treat the soil in the fall or the very early spring to give the lime a chance to work. The rule of thumb among gardeners is to sprinkle enough limestone on the garden so that it looks like a light snowfall, or like the powdered sugar on a doughnut. If you add lime to your garden in the fall, test the pH again in the early spring to see if the soil is now in the range you need it to be. If not, you may want to treat it again with another light application. Rake the limestone into the surface and water it. If you are liming early in the spring and your area gets rain, it may be enough to let the spring rains soak the lime into the soil.
Sulphur also does not work instantly. Microbes in the soil break down sulphur into sulfate, and this can take several months. Because sulphur relies on living creatures for this transformation, you should apply it in the spring when soil microbes will be active. The amount of sulphur you add will depend on the composition of your soil. If it has more sand, more silt, or more clay, the amounts you have to add will differ. If the soil contains a lot of calcium carbonate, you will need additional sulphur to decrease the pH. Detailed instructions for determining how much sulphur to add can be found in this fact sheet produced by the Ohio State University Extension: http://ohioline.osu.edu/agf-fact/pdf/0507.pdf.
Now that you have tested your soil and know where you want to put your compost, you can prepare the compost for use by sifting it. This step is important because it will remove large, undecayed pieces of compost and will give you a uniform product to work with.
Making a Compost Sifter
Even matured compost can sometimes be too coarse to use right out of the bin or pile. If you plan to use compost in containers, as a growing medium for new seedlings, or around flower beds or delicate vegetables, you will have to screen out the larger pieces. The simplest way to screen compost is in a compost sifter, which is a wooden box with a metal screen attached to the bottom. Simply put handfuls of compost into the sifter, and shake it lightly from side to side. The finished compost will pass through the screen and the large, uncomposted pieces will remain so you can return them to the bin where they can decompose further. Here are instructions for making a simple compost sifter. You can alter the dimensions if you want a bigger or smaller one — for example, if you want to make one that exactly fits over your wheelbarrow. These instructions were adapted from the book, Basic Composting.
Supplies and tools
• One 1x6, 8 feet long
• 18-inch x 24-inch piece of ½-inch wire mesh (hardware cloth)
• 12 2-inch galvanized deck screws
• Four 1 5/8-inch galvanized deck screws
• Hammer
• Wire clippers
• Staple gun and ½-inch staples
• Drill with 1/8-inch bit, Phillips screwdriver bit, and countersink bit
• Crosscut saw or circular saw
• Two sawhorses
• Carpenter’s square
• Tape measure
• Coarse sand paper
• Pencil
Instructions
Measuring
1. Measure an 18-inch by 24-inch rectangle of hardware cloth and cut with the wire clippers.
2. Measure and mark a 3/8-inch line along the full length of the 1x6 board.
3. Measure and mark two 17-inch lengths and two 24 ½-inch lengths on the board.
Cutting
4. Support the board on two sawhorses and use the circular saw (or hand saw) to cut the 3/8-inch strip off the edge of the board. If you find it difficult to make such a long straight cut, try cutting along the marks made in Step 3 before cutting the 3/8-inch strip off. That way you can make four shorter cuts, which may be more accurate.
5. Cut the strip into four sections on the marks made in Step 3.
6. Cut the remaining board into four sections on the marks made in Step 3.
Marking and Drilling
7. Mark drilling holes 3/8 inch from each end of each of the 24 ½-inch boards as follows: one hole in the center and the other two ¾ inch from each long edge as shown below. In the diagram below, the width of the board in the diagram is shown as 5 5/8 inch because 3/8 inch was removed in Step 4. This is an approximation because 1x6s are not really a full 6 inches wide.
8. Using the 1/8-inch drill bit, drill the marked holes on each end of each of the 24 ½-inch boards.
9. On each 3/8-inch wood strip, mark, and drill holes ¾ inch from both ends and about every 4 inches in between as shown below. Diagram is not to scale.
10. Using the countersink bit, countersink all the drilled holes deep enough to accommodate the head of the deck screws.
Assembling
11. Using the 12 2-inch deck screws and the Phillips screwdriver bit, attach the 24 ½-inch boards to the 17-inch boards to form a rectangle, placing the longer boards outside the shorter ones as shown below and using three screws on each corner. Use the carpenter’s square to ensure the rectangle is square as you assemble it.
12. Use the staple gun to attach the hardware cloth to the frame, stapling about every 3 inches around the frame.
13. Use the hammer to ensure the staples are secure in the wood frame.
14. Using the 1 5/8-inch deck screws, attach the 3/8-inch wood strip around the bottom of the frame, covering and securing the hardware cloth.
15. Sand the rough edges with the sand paper.
Using
To use your screen, place it over a wheelbarrow or large container and pour in finished compost, about 1 gallon at a time, shaking the screen from side to side to let the finished compost fall through the holes. Return any large pieces back to the compost bin.
Making Compost Tea
Compost tea is a solution made of finished compost and water. Just like compost, it is full of healthy microbes and nutrients, and because it is in a liquid form, plants can absorb it quickly. Compost tea can be aerated using aquarium pumps and other means. Aeration is the process of introducing air into the tea, which helps keep the microbes in it alive so that they can reproduce. Vigorously stirring the tea daily will also help incorporate some air into the mixture without the trouble and expense of pumps, but it is not as efficient at aerating the water.
Supplies and Tools
• 5-gallon bucket
• Burlap bag or other cloth sack
• Short length of rope, such as hay rope
• Rocks (to weigh the sack down)
• Fish tank bubbler or aerator
Instructions
1. Fill a burlap bag with finished compost. Tie the top shut. As with any kind of tea, adding more of the active ingredient — in this case compost — will make the tea stronger, but to make 5 gallons of tea, about 1 gallon of compost should be enough.
2. Put the bag into the 5-gallon bucket, and weight it down with rocks if necessary.
3. Fill the container with water (the ratio should be about five parts water to one part compost), and let the compost soak for several days, stirring it at least once a day to aerate it. You can also aerate it using a fish tank aerator or bubbler. You can use an external pump with a long hose leading into the bottom of compost tea bucket or a submersible aerator attached to the side of the bucket with one or more hoses extending down into the tea. Whichever kind you choose, make sure to follow all safety instructions that come with the aerator.
4. Remove the bag and squeeze the excess water out of the bag. You can re-use the bag several times. If you do not plan to make additional compost tea, you may take the compost that was in the bag and add it to the garden or back into the compost pile if it is not done composting.
5. Check that the compost tea is good to use. It should smell earthy and fresh. If it smells like sulfur or smells sour or spoiled, do not use it. Instead, pour it back onto the compost pile and try again with different compost. The sour smell comes from anaerobic bacteria, which can be discouraged by frequent stirring or mechanical aeration.
How to use compost tea
1. Strain out any large bits of compost material that may have escaped the bag. You can do this by using a few layers of cheesecloth stretched over a second bucket or by using a small fish net to scoop out visible pieces.
2. Dilute the tea — ten parts water to one part tea.
3. Use compost tea to water plants every one to two weeks.
4. You can also use the tea as a foliar fertilizer by spraying the tops and bottoms of leaves. (A foliar fertilizer is one that is sprayed directly onto the foliage — leaves and stems — rather than on the soil.) To help the tea adhere to the leaves, you may add one drop of clear liquid soap (not detergent and not an anti-bacterial formula) to the mixture. The soap will allow the liquid to spread smoothly over the leaves instead of forming droplets. This helps the tea stick to the leaves. If you do not want to spray soap on food crops, you can find various organic products that can accomplish the same task for sale at gardening supply stores or online. These products are called surfactants, and they help the compost tea, pesticides, and other liquid sprays cling to the leaves by breaking the surface tension of the liquid. This causes the liquid to form a sheet over the leaves rather than forming little droplets that are not as effective at transferring their ingredients to the plant.
5. Spray plants with a fine mist in the morning or evening when it is cool (below 72 degrees), not during periods of bright sunlight or when temperatures are over 80 degrees. When it is cool, the pores on the leaves are open and the fertilizer can penetrate the leaves more easily.
Although it seems to take a long time to make compost, once you start, you will have a continuous supply for as long as you keep doing it. Getting to the point of sifting it, making tea from it, and applying it to the garden provides a great feeling of accomplishment, but it is still just part of the ongoing cycle. The plants you feed today will turn into the compost materials you will pile up this fall so that the cycle may continue.
Case Study
Marianne Carlson
Amateur composter
Fort Dodge, Iowa
My compost system consists of a plastic ice cream bucket under the sink. When that gets full, I put it in a chicken-wire compost bin outside and turn the compost with a potato fork. Compost is a beautiful, rich material. It is wonderful. The worms you get in there are huge. Fishermen ought to do this.
I started to compost because I had a lot of yard waste, and waste from salads, vegetables, and canning, such as skins from tomatoes and peppers. We eat a lot of salads at our house. Start eating the way you are supposed to — eat your vegetables — and composting just comes naturally. If you want to spend $50, you can buy a fancy unit for your counter, but it does not have to be complicated.
I do not always follow the rules. They say compost has to be a certain temperature, and that you have to let it get hot enough to kill all the seeds and germs. In my case that does not always happen. I have had decorative gourds growing out of my compost pile, miniature white pumpkins, and cannas. I had thrown away some canna bulbs; I thought they were dead, but they were not. They stayed warm enough in there over the winter, and they sprouted. And apparently, with my gourds and pumpkins, it was not hot enough to kill the seeds, which was a plus as far as I was concerned. It is right by my rhubarb patch, which loves the compost. Rhubarb is a heavy eater.
I compost grass clippings, although you should not use them if you treat your yard, and you do not want too many grass clippings because that becomes overwhelming. I also compost kitchen scraps, yard waste, squash peelings, apple cores, and banana peels. Do not compost meat, bones, or anything similar, or you are asking for trouble from critters.
Composting can be as much or as little work as you want. I like having it in three stages: the first, where the ingredients are all piled up and mixed together; the second stage, where it is brewed awhile; and the third, where it is ready to be used. You can get real complicated as far as having air space underneath, but that is not for me. I just do it my way. I make it up as I go along.
The only problems I have experienced are with grass clippings. Make sure you do not have too many because they become rancid very quickly. That was the only problem I have ever had.
The most important thing about composting is that it is one less thing that goes to the city dump. They do not have to pick up many bags of garbage at my house. So, that is a plus; it keeps it out of the landfill. It is a plus for your yard, and it is good for some of the critters over the winter. Sometimes the birds and rabbits will feed on the compost. I do not spend much on soil enrichment materials. What I like about compost is what it does to your soil.