not organic, it can contain methoxichlor pesticide
residues.) Remember that too much nitrogen in your soil
can cause the soil’s all-important organic matter to break
down too quickly.
PHOSPHORUS
Phosphate Rock
11.5% to 17.5% total P. Lasts 3 to 5 years. Use 4.5 to
133 ⁄ 5 pounds (1^1 ⁄ 3 to 4 quarts)/100 square feet (see this
page). Very slow releasing.
SOFT PHOSPHATE (COLLOIDAL)
8% total P; 2% available P. Lasts 2 to 3 years. Use 9 to
271 ⁄ 5 pounds (1^1 ⁄ 3 to 4 quarts)/100 square feet (see this
page). Its clay base makes it more available to plants
than the phosphorus in phosphate rock, though the two
are used interchangeably. It becomes available over two
to three years.
POTASSIUM
Wood Ash
1% to 10% K. Lasts 6 months. Use a maximum of 1.5
pounds (1¾ quarts)/100 square feet. It becomes
available over a six-month period. Ash from wood is