GROW POWDER

Article Tools

Image Gallery

Print

E-mail

Comments

RSS

• Blood meal (12.5% N, 1.3% P, 0.7% K). Dried blood (again from slaughterhouses) is a rich source of quick-acting nitrogen. But it's expensive, so most gardeners use it only on small plots. Blood meal is also an excellent nitrogen source for the compost pile if you have little access to manures, green matter or other nitrogen sources. Use sparingly (no more than 3 lb./100 sq. ft.)—it can burn plants. Blood meal lasts up to 4 months and is reputed to repel deer and rabbits.

• Fish meal (10.5% N, 6% P, 0% K). Fish meal, made from dried fish-processing wastes, contains a good supply of trace minerals. Use 5 lb./100 sq. ft. Lasts 6-8 months. • Leather meal or leather dust (5.5-12% N, 0% P, 0% K). This dried leather-tankage product is one of the more suspect natural amendments, due to the chemicals used in its processing. (Some sources are cleaner than others.) Use up to 2 lb./100 sq. ft. Lasts 12 months. • Soybean meal (6% N, 2% P, 2% K). Soybean meal is a natural by-product of soybean oil processing. Use 5 lb./100 sq. ft. Lasts 3-5 months depending on the grind. • Cottonseed meal (3-6% N, 2% P, 1-2% K). Made from cleaned cottonseed that has been freed of oils, this nitrogen source has recently fallen into disfavor with some organic growers. Not only does it naturally acidify the soil, but it may contain high amounts of pesticide residues. (Some distributors claim their product is from a minimally sprayed source.) Use up to 101b./100 sq. ft. Lasts 4-6 months.

Phosphorus (P) Sources: • Bone meal (3% N, 20% P, 0% K and 20-30% calcium). Farmers used to save and grind bones after butchering, but slaughterhouses do that job today. This excellent source of quick phosphorus (though somewhat expensive for large gardens) comes raw or, more commonly, steamed and powdered. Use up to 5 lb./100 sq. ft. Lasts 12 months or longer. • Rock phosphate or phosphate rock (0% N, 33% P, 0% K, plus 30% calcium and many trace minerals). Mined in Florida, Tennessee and the western U.S., this is a very slowreleasing amendment. Some growers swear by it for long-term slow release (often using it in conjunction with quickeracting colloidal phosphate). Some others don't want to wait for it to take effect. Use up to 10 lb./100 sq. ft. Lasts up to 10 years. • Colloidal or soft rock phosphate: (0% N, 1820% P, 0% K, plus 20% calcium and many trace minerals). This fine sediment results from the hydraulic mining of phosphate rock but is quicker-acting than the straight stone. Use up to 10 Ib./100 sq. ft. Lasts 2-3 years.

Potash (K) or Potassium Sources: • Greensand or glauconite (0% N,1.5% P, 6-7% K, plus 50% silica, 18-23% iron oxide and 22 trace minerals). This mined sea deposit has a pleasant odor and is hefty enough not to easily get wind-blown when broadcast. The greener it is, the more potassium it contains. Use up to 10 lb./100 sq. ft. Lasts up to 10 years. • Granite meal or dust, or crushed granite (0% N, 0% P, 3-5% K, plus 67% silica and trace minerals). Literally, pulverized granite rock. Though some growers criticize granite meal as being too slow-releasing, others praise it (and greensand) for its gentle breakdown rate and high silica content (silica plays an important role in overall soil fertility).

RSS | Comments | E-mail | Print