Soil conditions may vary from backyard to backyard. For the most efficient and effective use of organic soil amendments, a soil test is advisable, if possible. Even a simple test using a LaMotte soil test kit can help you to judge what your soil needs for 3 key elements. If you live in the Menlo Park/Palo Alto/Mountain View area and choose not to perform a soil test or have one done for you, the recommendations on p. 4 of this leaflet can help you to estimate the amendments to apply.

If you use a LaMotte soil test kit to test your soil, you should use the amendment recommendations for N, P, and K on p. 45 of How To Grow More Vegetables.

Especially for a garden of 500 sq ft or more, it is best to have a professional soil test performed. A very good soil testing service is:

Timberleaf Soil Testing
39648 Old Spring Road
Murrieta CA 92563
Phone/Fax (951) 677-7510

As a first step, write for free information and a sampling kit. You should have their basic and trace mineral tests performed. These will include pH, organic matter, nitrogen, phosphorus, potassium, calcium, and trace minerals. The cost for both will be about $55.00. In addition to the results, you will receive an easy-to-understand interpretation and specific recommendations for correcting deficiencies. If you are mini-farming or gardening 500 sq ft or more, the soil test should more than pay for itself due to increased yields and reduced fertilizer expenses.

A pH reading tells you the relative acidity/alkalinity of the soil. Most vegetables will grow well in a range from 6.0 to 7.0. In extremely acid or extremely alkaline soils, valuable nutrients are tied up and thus unavailable to the plants. An acid soil can be sweetened by the addition of dolomite lime.

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N, P, and K refer to the three main nutrients plants need: NITROGEN for green growth and in compost piles to speed decomposition; PHOSPHORUS for energy, root growth, disease resistance, and production of good fruits, vegetables, flowers and seeds; and POTASH for strong stems, vigorous roots and increased disease resistance.

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Calcium helps break up clay and release nutrients tied up in alkaline soils. It is especially good for cabbage family crops (and can help keep your tomatoes from getting blossom end rot).

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Plants also need HUMUS (with its organic matter and minerals) which is produced by decaying organic matter such as compost, manure, rice hulls and cover crops (compost crops). An alkaline soil can be brought closer to neutral by compost or manure. Compost has a buffering effect on soil, correcting both acid and alkaline conditions.

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(application rates are for 100 sq. ft.)

Add all amendments after double-digging. For the first double-dig, compost may be added before double-digging; see How To Grow More Vegetables, pp. 10-12, 14).

(1) Beginning with the 6th year, your legumes, compost crops and recycled plant material (in the form of compost) can provide most of your nitrogen, phosphorus and potash. Double-check this periodically with a soil test.

(2) Nitrogen Å (% of protein) / 6.25. The 1st & 2nd Yr amounts will provide 0.4 lb pure N / 100 sq ft.

(3) For trace minerals: kelp meal is up to 33% trace minerals. Be sure to use cold-water kelp.

(4) Save your own.

(5) Top priority in typical adobe soil. Breaks up clay, improves drainage, releases nutrients and lowers pH.

(6) This amount of compost assumes a compost recipe that results in cured compost which contains 50% soil by volume. Eight cubic feet (12 five-gallon buckets) of cured compost will provide one inch of compost for 100 sq ft. Two cubic feet will provide 1/4 inch of compost for 100 sq ft. You can substitute aged manure for compost the first year if you do not have a ready source of compost; use half the amount recommended above.

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To revitalize an old lawn: Use 7 lb alfalfa meal, 4 lb soft phosphate, and 1 lb kelp meal per 100 sq ft. Apply in spring, and water well twice a week for 2 weeks. You should see results in 6 weeks.

Fruit trees: Use 2 heaping tablespoons alfalfa meal per foot of height, up to 4 lb soft phosphate per full-grown tree, and a light sprinkling of kelp meal (up to 1/4 lb per full-grown tree) around the drip line. Apply in spring when leaves first start to appear, and water in well. Growing compost crops around full-grown trees (keeping the crops 2 ft away from the trunk) is beneficial. Make compost without soil for fruit trees and other perennials, and use half the recommendation given in the General Fertilizer Program above.

Citrus trees: Same as fruit trees with the addition of 5 to 8 lb phosphate rock to full-grown trees once every 3 to 5 years. Line the planting hole with crushed red rock for a long-lasting source of iron.

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