Compost for Vegetable Producers
Compiled by Brian Caldwell, Extension Educator

What is compost?

Compost is made from manures and other bulky organic materials such as wood chips, leaves, etc. that are mixed together in piles and allowed to heat up. The piles may be remixed and reheated several times. This process breaks the original materials down into a black soil-like substance with an earthy smell. The original carbon content is reduced by about half, and nutrients are mostly in a more stable form.

What is the point of using compost in your vegetable operation?

1. Improve soil quality. The root zone environment can be improved by compost additions, by allowing for better water retention and penetration, and reducing compaction. Plants will be able to better withstand stress.
2. Add a source of slow-release nutrients. Compost products can typically have from about a 1-1-1 (cost: around $15+/ton) to about a 5-5-5 (cost: around $60-200+/ton) total analysis (plus some calcium, magnesium, sulfur, and micronutrients too), but much of this is released slowly. Therefore, it is available to the plants later in the season, and its nitrogen does not tend to leach away into the ground water.
3. Some compost products can enhance plant resistance to soilborne diseases. How this works is not clear, though in some cases the compost organisms present a weak "challenge" to the plant. This stimulates the plant's defenses. For direct-seeded crops, that leads to better stands.
4. You can also help make local agriculture more viable by giving livestock producers a market for their "value-added" excess manure.

Organic producers say that the carbon compounds (organic matter, mostly) in compost feed soil microorganisms, which create a balanced, buffered soil ecosystem that is not so prone to heavy buildups of pathogens as a simplified soil without much active organic matter.

How much compost do you need?

If you are using commercial fertilizers, applying compost to your fields at rates of as little as 2 tons per acre can show soil quality and disease suppression benefits over time. You will also get nutrients. For instance, if the analysis of the compost is 1-1-1, you could safely deduct 20 pounds each of N-P-K from your fertilizer applications the first year, after spreading it at the 2 ton rate. After 3 years, you could deduct 40 pounds of each nutrient because you would still be getting some residual from earlier applications.

How is compost applied?

Most low-analysis products are applied with a manure spreader. The higher-analysis products will go through lime spreaders. Pelleted forms (the most expensive) are suitable for fertilizer spreaders and sidedressing units. Be sure to ask the supplier about what sort of equipment is needed to apply the compost at the rate you want to use. It is best to concentrate the more expensive, high-analysis products near the crop, while the lower-analysis ones can be broadcast.

It may be too late now to apply compost to your early crops, but you can still sidedress with it and give it a try on later plantings. Try it on part of a crop and compare!

Will compost be a source of pests?

Properly made compost is virtually free of viable weed seeds, insects, and diseases. It is very unlikely to introduce a problem into your soil that you don't already have. Raw manure or partially composted products will generally contain weed seeds.

Sources of compost

AA Dairy, Candor, Wayne Aman, 659-3200, farm-produced dairy compost

Simmons Country Needs and Feeds, Berkshire, 657-2582, Fertrell brand

Bion Soil, Liverpool, Bill Galliger, 315-451-6372 (Amherst office 1-800-769-BION)

McEnroe Organic, Hudson Valley, Ray McEnroe, 518-789-3259

Krehres Compost, Clarence, 716-759-6802, bulk 5-5-2 poultry compost product @ $60/ton FOB

Wegmans Compost, Wayne County, 315-594-2906

Your local Agway carries a bagged compost product.