Agriculture Reference
In-Depth Information
Vermiculite enhances the water-holding capacity of the soil.
pH amendments don't work quickly. Wait 40 to 60 days after
adding the amendments, and then retest the soil before adding
any more. If amendments are added too quickly, they can
build up in the soil and make it inhospitable for growing
things.
Fertilizers
The fertility of soil is measured by its content of nitrogen,
phosphorus, and potassium, and fertilizers are rated the same
way, using a series of numbers called “NPK.” The N in NPK
stands for nitrogen, the P for phosphate, and the K for
potassium. A bag of fertilizer will be marked with the NPK in
a format that lists the percentage content of each nutrient,
separated by dashes. So, for example, a bag of fertilizer
labeled “5-10-5” is 5% nitrogen, 10% phosphate, and 5%
potassium.
A completely depleted garden soil with no detectable levels
of NPK requires only 4.6 ounces of N, 5 ounces of P, and 5.4
ounces of K per 100 square feet to yield a “sufficient” soil. In
the case of root crops, less than 3 ounces of N are needed.
