Symptoms of Orchid Fertilizer Deficiency
Orchids, like all plants, require nutrition in the form of fertilization. But unlike most other plants, orchids need specific types of fertilization or, depending on how they are planted, they may not need any supplementation.
However, since many orchids are grown inside or outside for a limited time it becomes necessary to supplement this natural nutrition with orchid fertilizer. The type of orchid and the potting medium will determine both the amount of orchid fertilizer and the quantity used.
Osmunda is a natural planting medium that decays slowly and provides some nutrients through its decomposition. However, a weak solution of a water-soluble orchid fertilizer sprayed on the leaves is helpful although some growers maintain that additional feeding is not necessary if osmunda is used as the potting medium.
Recently the use of bark as a planting medium has become popular, however, since it does not provide any nutrient value, growing plants will require an orchid fertilizer supplement. Orchids that are planted in tree fern or tree-fern slabs will find that a light foliar feeding with a balanced orchid fertilizer is beneficial. If your plant is potted in any one of the several orchid mixes which are composed of bark, fiber, sphagnum moss and the like then it will require additional fertilizing. If it is not planted in osmunda then you will need a fertilizer that is relatively high in nitrogen.
The three elements contained in all fertilizers are nitrogen, phosphorous and potash (potassium). Other trace elements may also be added by the manufacturer.The nitrogen value is the first number shown in any formulation and is the element that will give orchids their healthy green color. However, too much of a good thing can cause too much growth and may ultimately result in rot. Too much nitrogen may also delay or prevent the development of flowers. If the overall growth of the plant seems to be retarded it may be due to a lack of nitrogen. Discoloration of the leaves particularly older leaves becoming yellow is often the first symptom that the plant is not getting enough nitrogen. Furthermore, the development of new growths will be slow and those that do emerge will be small. In addition, leaves will lose their sheen and feel hard to the touch. If this conditon is left untreated they may completely lose their green coloring.
It may be difficult to determine if a plant is suffering from a nitrogen deficiency or if it is being overwatered. To determine if nitrogen or overwatering is the problem check the roots. If the lack of nitrogen is the cause the roots will be healtlhy wheras overwatering can cause root rot.
When a plant needs to be repotted because the roots are hanging over the sides it may seem as if it is under fertilized even though that is not the case. This is because there is an overcrowding of the roots and there is not enough potting medium to retain the fertilizer resulting in starvation. It may be difficut to overcome this deficiency even by foliar feeding of the arial roots.
When you attempt to correct a lack of nitrogen the first number (nitrogen) in the fertilizer formula must not only supply a high percentage of this element but it must be greater than each of the other numbers (phosphorous and potash). For example 20-10-10.
The percentage of phosphorous is indicated by the second number in the fertilizer formula. This element is necessary to promote budding and stimulate blooming. It is also necessary for the ripening and maturing of the plants. When you notice that buds are beginning to form or when you want to promote budding you should apply an orchid fertilizer that has a higher phosphorous percentage than the other two elements. Such as 10-30-20. It should be noted that you should not use phosphorous alone or as a higher percentage than the other two elements on a continuous basis and it is highly recommended that it not be used more than two or three times consecutively. It is unusual to find a real deficiency of phosphorous in orchids and when it does occur it is usually due to feeding the plant a strict diet of nitrogen for an extended period of time.
A reddish pigmentation on the leaves of plants which produce colored flowers is an indication of a phosphorous deficiency. In addition, new growths will not achieve their normal size and the plant may never bloom. The process of correcting for a lack of phosphorous can take as long as a year before the plant regains normal health.
The last item in the fertilizer formula is potash or potassium and is responsible for building strong roots. Most orchid fertilizer mixes usually have enough potassium and trace elements so that a potassium deficiency is seldom an issue. If, however, the flowers become paler with each successive year and there is a decrease in the number of buds it may be due to a lack of this element.
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