In the early stages of phosphorus deficiency the plants look almost
too healthy. Growth is normal but undersized. Plants
become dark green frequently changing to purple, especially the
undersides of leaves. Sometimes stems also take on this color.
Leaves then yellow in the final stages. The plant has poor
flowering and fruiting habits. Most common in cold, wet or very
acidic (below pH5) soils and very alkaline soils (above pH 7.3).
Phosphorus in needed for root formation, flowering, fruiting
In potassium deficiency, the older leaves become mottled or spotted,
edges become dry and scorched. Dead spots begin to appear, the
stems are weak, root systems poor, and fruit ripens unevenly.
Potassium deficiency causes a reduction in disease resistance and
makes the plant less storable. It is more common in sandy or
acidic soils, also where there are excess calcium or magnesium levels
in the soil. Potassium is important for the formation of
flowers, fruit, leaves and growing tip. Potassium helps with
photosynthesis at low light level and in internal water regulation.
Potassium improves flavor, fruit, vegetable and flower color. It
also provides protection from insect damage, disease, and frost.
Sulfur deficiency closely resembles nitrogen deficiency. The
plants turn pale green, the effects show up first in young growth.
Leaves turn yellow but they don't dry out, and stems are weak.
Legumes are most affected. Sandy or very wet soils, and soils
containing excessive amounts of nitrogen are the most common soil
types with a potassium deficiency. Together with nitrogen it
makes protoplasm for plant cells.
A zinc deficiency can be similar to a nitrogen deficiency with
rolled leaf margins. Chlorosis shows up first in young leaves,
which are also reduced in size. Leaves are closely spaced,
forming rosettes, and may be deformed. There is poor nitrogen
formation in legumes. Soils that are sandy and acidic or
alkaline and rich in humus, or excessively high in phosphates,
nitrogen, calcium, or aluminum will most often be zinc deficient.
Zinc aids in the formation of growth hormones, protein synthesis, seed
and grain production, and plant maturation.
The observant farmer and gardener will notice subtle changes in the
weed populations as the soil changes. As the soil improves,
chickweed, chicory, common groundsel, common horehound, and lambs
quarter become the dominant weeds. However, if the daisy, wild
carrot, mugwort, common mullein, wild parsnip, wild radish, and
biennial wormwood become dominant, thatís a sign of the soilís low
fertility and can be corrected. The addition of well-balanced
compost, organic manures, and other fertilizers together with certain
tillage and drainage practices may be required to return the soil back
to a healthy, well balanced, and productive soil.
There will always be a battle between man and weed, but knowing that
weeds can be used not only as a soil indicator, but also the flower of
many weeds provide essential nectar and pollen, the foods needed by
beneficial insects to complete their life cycle. Most insect
pests would actually prefer to dine on weeds rather than your
deliberately planted crops, if given the choice, so weeds can be good
companion plants, and last, but not least, theyíre edible. I can
never defeat the weed, so I must live with the weed. Now I have
an excuse for not spending hours pulling out the weeds in the garden.
Now I can spend time wandering in my blended garden enjoying both
plants and weeds. They are rebels, just like me.