Rock Phosphate is one of the best natural sources of phosphorus (P) and calcium (Ca).
Rock Phosphate contains 7% immediately available Phosphorus (P205 ), averages 30% Calcium (Ca) and possesses numerous trace minerals for up to 5 years after application, depending on the crop and soil conditions. A micronized powder form and can be applied with common fertilizer spreaders or broadcast by hand. Phosphate is immediately available to plants and will act as a long-term source of phosphorus. Rock Phosphate should be plowed under or turned into the soil. Unlike chemically made phosphates, rock phosphate is insoluble in water, will not leach away, and therefore is long-lasting.
Annual plants absorb up to 60 percent of its total phosphate needs within the first few weeks of its life. If it does not receive phosphate then it is always behind and never catches up. Rock phosphate used directly under the seed or transplant at planting time is the very best method of application, especially in low acid or high alkaline soils. It is not as critical but still beneficial in slightly acidic to neutral soils. It is almost impossible to overuse soft rock phosphate, you can grow beautiful plants directly in it without any harmful effects.
Rock phosphate should be applied and worked into the soil prior to planting along with other organic amendments. In alkaline soils, apply the phosphate directly under the seed or transplants so the small roots don’t have to search for it. This is especially important in the spring.
- Amending soil: Apply up to 5 lbs. / 100 sq.ft. or 1 ton / acre on phosphate deficient soils, and less on fertile soils. If planting in rows, mix with the seed or starter plant and apply up to 1 lb. per 50 ft of row.
- Compost Tea: Use as a food source for fungi. To increase the growth of fungi in your compost tea, pretreat your compost with 1/4 tsp of finely ground soft rock phosphate and 1 tsp organic oat or wheat flour for each cup of worm castings, forest humus, mushroom compost, or mature compost.
- Add 1 teaspoon per 5 gallons of compost tea
- General Use: Mix 2.5 tbsp. per gallon of water for lawns, gardens, trees and shrubs (will cover 40 sq. ft.).
- Trees and perennials: Apply 1 - 10 lb. per planting hole, depending on plant size.
- Transplants: 1 - 2 tablespoons per 4-6" planting hole.
- Potted plants: Mix 1 teaspoon per 2" pot diameter with potting soil before planting.
Nitrogen (N)............ 0%
Phosphorus (P)........ 7%
Potassium (K)......... 0%
Calcium (Ca)........ 31%
Iron (Fe).................. 1%
Total Phosphorus.. 20%