How to Grow More Vegetables : And Fruits, Nuts ... - Shroomery

54 FERTILIZATION
Soft Phosphate (Colloidal)
~8% total P; ~2% available P. Lasts 2 to 3 years. Use up to 18 lbs
(2 2 ⁄ 3 qt)/100 sq ft. Clay base makes it more available to plants
than the phosphorus in phosphate rock, though the two are
used interchangeably.
POTASSIUM
Wood Ash
1% to 10% K. Lasts 6 months. Use up to 1.5 lbs (13 ⁄ 4 qt)/
100 sq ft. Ash from wood is high in potassium and helps repel
maggots. Ash also has an alkaline effect on the soil, so use it
with care if your soil pH is above 6.5. Black wood ash is best.
Wood ash provides strength and plant essence, aids in insect
control, and is a flavor enhancer for vegetables, especially
lettuce and tomatoes. You can produce it with a controlled, soilcovered,
slow-burning fire built during a soft drizzle or rain.
This ash is higher in potassium and other minerals because
they do not readily escape into the atmosphere as the wood is
consumed by fire. Wood ash should be stored in a tight
container until it is used; exposure to air will destroy much of
its nutrient value. Grey wood ash from a fireplace may be used
if it is from wood and not from colored or slick paper.
Crushed Granite (Finely Ground)
3% to 5% K. Lasts up to 10 years. Use up to 8.5 lbs (3 1 ⁄ 2 qt)/
100 sq ft. It is a slow-releasing source of potassium and trace
minerals.
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.