and why did I look at this so late...? After extensive
searching - I "think" (pasted below) this is what I intended to lead John to. Every time I copy "it's address" - it sends me to another advertisement ~ Clever
, and that explains the looonnngg address above...
Anyway: here's "The Mountain" of info. There's a lost of leaf-yellowing possibilities, and perhaps more than you'd care to know - but it's all stuff we "should" know... Sorry about the Wild-add-chase!
by Rod Smith
Oregon Certified Nursery Professional
Â© 1999-2004 Rodney A. Smith
All rights reserved.
Plants need water, air, light, suitable temperature, and sixteen nutrients to grow. Plants get carbon, hydrogen and oxygen from air and water. The other thirteen nutrients come from the soil. Soil nutrients are divided into two groups according to the amounts needed by plants. The Macronutrients are nitrogen, phosphorus, potassium, calcium, magnesium, and sulfur. The Micronutrients, which are needed in only trace amounts, are iron, manganese, boron, zinc, copper, molybdenum and chlorine.
These nutrients are essential for plant growth. Plants will grow normally until they run short of one nutrient. Then growth is limited by the availability of that nutrient. Occasionally two or more nutrients will run short at the same time. If the nutrients are deficient, or too abundant, then plants will be discolored or deformed.The deficiency symptoms will indicate which nutrient or nutrients are needed. However, it is much better to supply additional nutrients before deficiency symptoms appear. A soil test will tell which nutrients are low before growth is affected.
MACRONUTRIENTS Nitrogen, N, stimulates leaf and stem growth. Nitrogen deficiency causes reduced growth and pale yellowish green leaves. The older leaves turn yellowish first since the nitrogen is readily moved from the old leaves to the new growth. If the soil is cold and wet, nitrogen in the soil is not as available to the plants. Excess nitrogen may cause potassium deficiency.
Phosphorus, P, is important in the germination and growth of seeds, the production of flowers and fruit, and the growth of roots. Phosphorus deficiency causes reduced growth and small leaves that drop early, starting with the oldest leaves. Leaf color is a dull, bluish green that becomes purplish or bronzy. Leaf edges often turn scorched brown. Excess phosphorus may cause potassium deficiency.
Potassium, K, promotes general vigor, disease resistance and sturdy growth. Potassium deficiency causes stunted growth with leaves close together. Starting with the older leaves, the leaf tips and edges turn scorched brown and leaf edges roll. Excess potassium may cause calcium and magnesium deficiencies.
Calcium, Ca, is a major ingredient in cell walls and is important for root growth, especially root tips. Calcium deficiency causes poorly developed roots with weak tips. Leaves are distorted with hooked tips and curled margins.
Magnesium, Mg, is vital to chlorophyll production and is important in most enzyme reactions. Magnesium deficiency causes different symptoms in different plants, but commonly includes leaf yellowing with brilliant tints. Leaves may suddenly drop off without withering. Symptoms show first on older leaves. Excess magnesium may cause calcium deficiency.
Sulfur, S, is an ingredient in proteins and is necessary for chlorophyll formation. Sulfur deficiency causes slow growth with small round leaves that roll upward and are stiff and brittle. Leaves drop off and tip buds die.
MICRONUTRIENTSIron, Fe, is necessary for chlorophyll formation and for oxygen transfer. Iron deficiency causes leaf yellowing while leaf veins stay green. Younger leaves are affected first. Excess lime may cause iron deficiency.
Manganese, Mn, is a catalyst for many enzymes and is important for chlorophyll formation. Manganese deficiency causes different symptoms in different plants, but commonly causes leaves to turn yellow while veins stay green. White or gray specks may appear on leaves. Older leaves are affected first. Excess manganese may cause iron deficiency and may cause symptoms similar to manganese deficiency.
Boron, B, is necessary for the movement of sugars, for reproduction, and for water intake by cells. It also tends to keep calcium in a soluble form. Boron deficiency causes distorted and dead growing tips, hollow stems and deformed fruit. Leaves are often scorched and curled and sometimes mottled and discolored. Young leaves are affected first. Excess boron may cause scorched leaf edges similar to potassium or magnesium deficiencies.
Zinc, Zn, is necessary for the production of proteins and affects plant size and maturity. Zinc deficiency causes leaf yellowing between the veins, usually with purple or dead spots starting with the older leaves. Leaves are close together, small and deformed. Fruiting is reduced. Excess zinc may cause iron deficiency.
Copper, Cu, is necessary for the production of proteins and is important for reproduction. Copper deficiencies causes bluish green leaves which may wither or fail to unfold. Younger leaf tips may be yellow at the edge. Growing tips may form rosettes. Excess copper may cause iron deficiency.
Molybdenum, Mo, is essential to nitrate enzymes and for the formation of root nodules in beans and peas. Molybdenum deficiencies cause yellow mottling and dead spots on the leaves. In some plants, the growing tips are distorted or killed.
Chlorine, Cl, may affect carbohydrate metabolism and photosynthesis. Chlorine deficiencies may cause stubby roots and wilting. Excess chlorine may cause leaf edges to scorch similar to potassium deficiency.