Plants Get Hungry Too

| 4/28/2013 11:26:44 AM

Tags: What 15 nutrients vegetables need, Plant micromutrients, , Karen Newcomb,

Karen NewcombAlthough nutrition is as important to plants as it is to people, many gardeners simply ignore the issue.  Then they wonder what’s wrong with their vegetables.

Vegetables generally need 15 nutrients for maximum growth.  Three elements—oxygen, carbon, and hydrogen—come from air and water.  The other 12 exist in the soil.  Nitrogen, phosphorus, and potassium are the major macronutrients needed by vegetables in large amounts.

Nitrogen, a major element in plant nutrition, produces leaf growth and gives leaves a vibrant dark green color.  It helps generate a healthy root system, increases the set of fruit, and nourishes soil microorganisms.  It is especially important for such leafy vegetables as cabbage, lettuce, spinach, and collardsNitrogen deficiency causes yellow leaves and stunted growth.  Excess nitrogen delays flowering, produces excessive growth, reduces the quality of fruits, and renders crops less resistant to disease.

Blood meal contains 7 to 15 percent nitrogen.  It can be mixed as a liquid fertilizer, using one tablespoon to a gallon of water.  Hoof and horn meal contains 7 to 15 percent nitrogen.  Cottonseed meal has 6 to 9 percent.  Fish meal and fish emulsion contain up to 10 percent nitrogen and nearly as much phosphorus.  Bonemeal may contain up to 3 percent nitrogen.  Follow directions on package.

Phosphorus stimulates early root formation, hastens maturity, and is important for the development of fruit, flowers, and seeds; it also helps provide disease resistance and winterkill protection.  A phosphorus deficiency causes dark or bluish green leaves followed by bronzing, reddening, or purpling, especially along veins and margins.  Lower leaves are sometimes yellow, drying to greenish brown or black.  Plants are often stunted, spindly, late to mature.  Excess phosphorus produces iron and zinc deficiencies in corn, beans, tomatoes, and other plants.

Phosphorus fertilizers include bonemeal, averaging 20 to 25 percent phosphoric acid, and phosphate rock, a finely ground rock powder that contains about 30 to 33 percent phosphoric acid, plus minor and trace elements.

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