Tip of the Day: Nitrogen Toxicity: Leaves are often dark green and in the early stages abundant with foliage. If excess is severe, leaves will dry and begin to fall off. Root system will remain under developed or deteriorate after time. Fruit and flower set will be inhibited or deformed. With breakdown of vascular tissue restricting water uptake. Stress resistance is drastically diminished. Phosphorus (P) Phosphorus is a component of certain enzymes and proteins, adenosine triphosphate (ATP), ribonucleic acids (RNA), deoxyribonucleic acids (DNA) and phytin. ATP is involved in various energy transfer reactions, and RNA and DNA are components of genetic information. Phosphorus (P) deficiency: during flowering. Fan leaves are dark green or red/purple, and may turn yellow. Leaves may curl under, go brown and die. Small-formed buds are another main symptom. Phosphorus deficiencies exhibit slow growing, weak and stunted plants with dark green or purple pigmentation in older leaves and stems. Some deficiency during flowering is normal, but too much shouldn’t be tolerated. Red petioles and stems are a normal, genetic characteristic for many varieties, plus it can also be a co-symptom of N, K, and Mg-deficiencies, so red stems are not a foolproof sign of P-deficiency. Too much P can lead to iron deficiency. Purpling: accumulation of anthocyanin pigments; causes an overall dark green color with a purple, red, or blue tint, and is the common sign of phosphate deficiency. Some plant species and varieties respond to phosphate deficiency by yellowing instead of purpling. Purpling is natural to some healthy ornamentals. Phosphorus (P) deficiency during vegetative growth. Many people mistaken this for a fungus, but look for the damage to occur near the end of leave, and leaves the color dull greyish with a very brittle texture. Phosphorus (P) Toxicity: This condition is rare and usually buffered by pH limitations. Excess phosphorus can interfere with the availability and stability of copper and zinc. Potassium (K) Potassium is involved in maintaining the water status of the plant and the tugor pressure of it’s cells and the opening and closing of the stomata. Potassium is required in the accumulation and translocation of carbohydrates. Lack of potassium will reduce yield and quality. Potassium deficiency: Older leaves are initially chlorotic but soon develop dark necrotic lesions (dead tissue). First apparent on the tips and margins of the leaves. Stem and branches may become weak and easily broken, the plant may also stretch. The plant will become susceptible to disease and toxicity. In addition to appearing to look like iron deficiency, the tips of the leaves curl and the edges burn and die. Potassium – Too much sodium (Na) displaces K, causing a K deficiency. Sources of high salinity are: baking soda (sodium bicarbonate “pH-up”), too much manure, and the use of water-softening filters (which should not be used). If the problem is Na, flush the soil. K can get locked up from too much Ca or ammonium nitrogen, and possibly cold weather. Potassium (K) Toxicity: Usually not absorbed excessively by plants. Excess potassium can aggravate the uptake of magnesium, manganese, zinc and iron and effect the availability of calcium. Magnesium (Mg) Magnesium is a component of the chlorophyll molecule and serves as a cofactor in most enzymes. Magnesium (Mg) deficiency: Magnesium deficiency will exhibit a yellowing (which may turn brown) and interveinal chlorosis beginning in the older leaves. The older leaves will be the first to develop interveinal chlorosis. Starting at leaf margin or tip and progressing inward between the veins. Notice how the veins remain somewhat green. Notice howthe leaves curl upwards like they’re praying? They’re praying for Mg! The tips may also twist. This can be quickly resolved by watering with 1 tablespoon Epsom salts/gallon of water. Until you can correct nutrient lockout, try foliar feeding. That way the plants get all the nitrogen and Mg they need. indoor-botanics.co.uk/atami/89-atami-Bloombastic.html #Cambridge #CherryHinton #Histon #Hardwick #Cambourne #Haverhill #Ely #Greenfingers #Luton #Bedford #Hitchin #London #GrowYourOwn #Newmarket #Horticulture #Hydroponic #GrowShop
Posted on: Tue, 03 Sep 2013 13:11:11 +0000
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