Agriculture Reference
In-Depth Information
worm castings, and bat guano. You can also add nitrogen to the soil by planting legumes as
cover crops (clover, peas, fava, and other beans), and by developing your own compost.
Phosphorus (P)
Phosphorus promotes root development, bloom, and strong structures (trunk and cor-
dons). Common sources of phosphorus are rock phosphate, bat guano, bone meal, and fish
meal. You can usually give an annual application of phosphorus along with nitrogen and
potassium. Phosphorus deficiency is harder to detect visually, but can be demonstrated by
a weak bloom and spindly structure.
Potassium (K)
Potassium promotes strong flowering, fruit production, and general health and resist-
ance to pests. Sources of potassium are sulfate of potash, muriate of potash, wood ash,
manures (such as chicken, turkey, or horse), and potassium nitrate. Potassium deficiencies
show up in midsummer to late summer with bronze-colored leaves. Some leaves may have
dark reddish spots, margins, blotches, or dead spots.
If you continue to build your soil and feed your vines, they are unlikely to suffer
from nutrient deficiencies. Be sure to identify any nutrient problems through a
petiole test. This leaf is showing signs of potassium deficiency.
