What are cover crops and green manures?

Cover crops are used primarily to protect fallow (unused) soil. In the North, gardeners usually plant them at the end of the season so their soil is not bare over the winter. Cold-hardy crops such as vetch and winter rye are best for overwintering. They will begin growing again in spring and need to be tilled in before you can plant your garden.

Green manures can also be planted in a new garden area the year before you plan to use it. They will choke out weeds and add a wealth of organic matter. Legumes, including field peas, soybeans, and alfalfa, will contribute both nitrogen and organic matter to the soil. Fast-growing grains and buckwheat produce the most organic matter and will smother competing weeds as they grow.

If your soil will be fallow for more than one growing season, you can plant perennial or biennial green manures, such as clover or alfalfa. All cover crops should be tilled in at least three weeks before the area is to be replanted, so the organic matter will already be partially decomposed at planting time.

What are liquid soil conditioners?
Liquid soil conditioners typically contain a blend of humic acid and catalytic enzymes, which are produced in a controlled environment by the same sort of microorganisms that are at work in your compost pile. When applied to your soil, their effect is similar to the effect you get when you add compost. Clay soils become easier to work and nutrients become more available; sandy soils are able to retain more water and nutrients.

Researchers have now isolated specific organic substances that solve specific soil problems. Soon you will be able to buy organic soil conditioners that have been specially selected for their effectiveness in opening up heavy soils or dislodging salts and other elements that have become tied up in the soil.

What is hardpan?

Hardpan is a dense layer of soil that restricts root growth and the movement of moisture, air and beneficial organisms through the soil. Hardpan is usually created by glacial action, heavy rain, or heavy equipment, and typically lies between 6 and 25 inches below the soil surface.

Farmers often cope with hardpans by using a chisel plow to cut and break up this dense layer of soil. Home gardeners can break up and mix the hardpan layer by “double digging” the soil. This involves removing 10 to 12 inches of topsoil and then working organic matter into the 12-inch layer of material that lies below. If the hardpan layer is not too deep, you can use a digging fork to puncture it and open up passages for air and water.

What does chelated mean?
Chelation is a process that joins a nutrient, such as iron, to a non-nutrient compound that can be easily absorbed by your plants.

What does 5-8-3 mean?
The numbers refer to the percentage by the net weight of total nitrogen (N; always the first number), available phosphorus (P; the second number), and soluble potash (K; the third number). In other words, a 5-8-3 fertilizer contains 5 percent nitrogen, 8 percent available phosphorus, and 3 percent soluble potash.

Labeling laws allow only the immediately available nutrients to be listed. That is why the nutrient analysis for organic fertilizers tends to be low. Most organic fertilizers actually have a higher nutrient content, but these nutrients gradually become available to plants over a period of months or even years.

What are the benefits of seaweed?

Seaweed contains at least sixty micronutrients, including iron, copper, zinc, boron, and manganese. Seaweed also contains a high concentration of natural growth hormones which allow it to grow rapidly in its natural environment. When applied to plants, these growth hormones stimulate root growth, reduce transplant shock, promote more rapid fruit set, increase frost resistance and improve storage life. Research has also revealed that seaweed contains antitoxins that help plants fend off bacteria, viruses, and pests.

Powdered seaweed (kelp meal) releases its nutrients gradually into the soil. Liquid seaweed makes these nutrients immediately available. Seaweed is not a complete fertilizer because it doesn’t provide adequate nitrogen and phosphorus for most plants. But it is an excellent part of a balanced soil-building program.

An excerpt from the article, “Building Healthy Soil“, by Kathy LaLiberte, courtesy of Gardener’s Supply Company.