Soil Modifiers

Dolomitic Lime

~25% Ca. ~6% to 14% Mg. A good source of calcium and magnesium to be used when both are needed. Do not use dolomitic lime in a soil with an adequate or high level of magnesium. Do not use lime to "sweeten" the compost pile as doing so will result in a serious loss of nitrogen. A layer of soil will discourage flies and reduce odors. 1 qt = about 3 lbs 8 oz.

High Calcium Lime (Calcite)

A good source of calcium when magnesium levels are too high for applying dolomitic lime. Oyster shell flour lime (~34% to 36% Ca) is a good substitute. 1 qt = about 30 oz.

Gypsum (Calcium Sulfate)

~23% Ca. ~19% S. Used to correct excess levels of exchangeable sodium. Apply only when recommended by a professional soil test. 1 qt = about 1 lb 4 oz.

Crushed Eggshells

High in calcium. Especially good for cabbage family crops.

Eggshells help break up clay and release nutrients tied up in alkaline soils. Use up to 2 lbs (1V4 qt)/100 sq ft. Dry them first.

Manure (All Types)

A good source of organic matter in the garden. The nutrient levels in each manure will depend on proper management of the curing process and on the amount of straw or sawdust in the manure. Optimally, do not use more than 4 cubic feet (6 5-gallon buckets) of aged manure per year (about 136 lbs dry weight, or a V2-inch layer). It is best to use manure that contains little undecomposed sawdust. Approximately 2 cubic feet (3 5-gallon buckets) of manure (50 lbs dry weight) applied per 100 square feet can lower the pH one point. Manure is a microbial life stimulant and an animal and plant essence that has been "composted" both inside the animal and outside in a curing pile. Avoid using too much manure because manures that do not contain much sawdust or straw can contain excess salt and imbalanced ratios of nitrogen, phosphorus, and potassium. The grow biointensive method uses as much (or more) phosphorus and potassium as nitrogen. This results in stronger, healthier plants. It is one difference between the grow biointensive method and the French intensive approach that depended heavily on the use of horse manure, which is about 3 parts nitrogen to 1 part phosphorus to 3 parts potassium. This ratio is unbalanced in favor of nitrogen, which in time results in weak and rank plant growth more susceptible to disease and insect attack. A ratio of 1 part nitrogen to 1 part phosphorus to 1 part potassium is better. Using a large amount of composted or aged manure is recommended as an alternative to compost only when compost is not available.

MANURES—SOLIDS (approximate)


1.50% N

1.00% P

.50% K


4.50% N

3.50% P

2.00% K

Dairy Cow

.56%% N

.23% P

.60% K


.69°% N

.24% P

.72% K


.50%% N

.32% P

.46% K


1.40% N

.48% P

1.20% K


.70% N

.55% P

Good compost is the most important part of the garden. It aerates soil, breaks up clay, binds together sand, improves drainage, prevents erosion, neutralizes toxins, holds precious moisture, releases essential nutrients, and feeds the microbiotic life of the soil, creating healthy conditions for natural antibiotics, worms, and beneficial fungi. Each 4-month growing season, use


In order to obtain a 1-inch layer of aged steer manure for use as compost on a 100-square-foot area, fodder for the animal to eat must be grown on a 500-square-foot area. This means an area four times as large as your growing area is being depleted of trace minerals and life-sustaining humus! Such a practice is not sustainable if used over a long period of time. When the proper compost crops are used instead, the compost materials for your 100-square-foot garden can be grown in just your 100-square-foot garden itself!

up to an inch of cured compost (8 cubic feet/100 square feet), which is about V3 of a cubic yard. (One cubic yard equals 27 cubic feet. Two cubic feet of cured compost will cover 100 square feet ¥4 inch deep.) Generally, use only a maximum 8 cubic feet cured compost made with equal amounts by weight of dry material, green material, and soil (or 4 cubic feet cured compost made without soil) per 100 square feet per 4- to 6-month crop to avoid using more than a sustainable amount of compost.

You should note the heavy emphasis that the grow biointensive method places on compost. The demand for organic fertilizers is increasing while the supply available to each person in the world is decreasing. Soon, few fertilizers will be available at reasonable prices. Also, the materials used to produce chemical fertilizers are becoming less available. Materials for grow biointensive compost, on the other hand, are plants and soil, which can be produced in a sustained way by a healthy garden. These compostable materials can be produced indefinitely if we take care of our soils and do not exhaust them. In fact, 96% of the total amount of nutrients needed for plant growth processes are obtained as plants use the sun's energy to work on elements already in the air and water.7 Soil and compost provide the rest.

grow biointensive compost (see "Compost") is high in most major and trace minerals. It also contains nitrogen and, when made properly, can be high in nitrogen. A thin layer of manure added to the soil during the fertilization stage can also provide nitrogen. Periodically growing legumes—such as peas, beans, clover, alfalfa, and vetch—in the planting beds will provide nitrogen, too. The nitrogen that the legumes fix from the air is released when their roots, stems, and leaves decompose. Compost, manure, wood ash, nitrogen from legumes, and nutrients from the growth of certain kinds of herbs and weeds in the beds (see "Companion Planting") supply the 4% of a plant's diet not provided by the air and water.

Organic Gardeners Composting

Organic Gardeners Composting

Have you always wanted to grow your own vegetables but didn't know what to do? Here are the best tips on how to become a true and envied organic gardner.

Get My Free Ebook

Post a comment