Manuaring

Under natural conditions , orchids get their necessary inorganic nutrients like, nitrogen , phosphorus , Potassium , Calcium , magnesium , iron and traces of manganese , boron, copper, zinc and molybdenum from the soil or the bark upon which they are growing and also from the atmosphere washed down by rain. The organic nutrients are supplied by the decaying vegetable and animal debris . When under cultivation , all these should be supplied to the orchid regularly , particularly if it is growing in media other than Osmunda fibre. Several fertiliser formulae have been recommended for orchids, taking into account their special requirements . Since orchids are generally very slowgrowing plants, the popular NPK mixtures , combined with frequent organic feeding ,is enough to meet their requirements . The propogation of one mineral to another should , of course , be adjusted according to age and growth rate of the plant. Larger quantities of nitrogen are needed when the plant is growing vigorously. When the plant has attained maturity , growth rate decreases and sometimes altogether stops and preparations for flowering are started . At this stage , nitrogen should be reduced and amount of phosphate increased in order to get a good crop of flowers .

There are also more elaborate formula for fertilizer solutions as the one given below.

The salts are dissolved in two pints of water and 1.4 cc of it is diluted to 4 pints of water (Cox, 1966). Sagarik and Siripong (1963) have a formula which includes all the trace elements as well.

The stock solution is prepared in distilled water and used immediately after diluting 1 cc to 100 cc with water.

Wherever bark is used as planting medium ,nitrogen should be supplied in extra amounts , because bacteria which act upon bark releasing minerals. consume a lot of nitrogen.

Organic manure which are usually given to orchids are fresh as well as dried cow-dung , dried leaves , fish manure , prawn meal , bone meal , oil cakes etc. Dried cowdung , dried leaves , prawn and bone meal are sometimes given mixed with the medium while potting . Fresh cow-dung , fish manure and oil cakes are best applied in liquid form, after two to three gallons of water in a tightly closed container for about two weeks . This is then passed through a muslin cloth and the filtrate diluted and sprayed .

Manuring once a week is the most generally accepted procedure . The fertiliser may be used in a more diluted form and supplied to the plant with every watering . Care should be taken not to give too much fertiliser or manure . When Orchids are grown in a media of broken roofing tiles and charcoal , complete fertiliser should be sprayed once a week , followed two days later by spraying with plenty of fresh water to wash away excess fertilisers accumulated in the neutral media . When using fertiliser mixtures sold by reputed firms strictly follow instructions supplied with the same.

Several organic substances are said to stimulate growth activities in orchids. For example beer, at the strength one quart per 10 gallons of water is reported to have beneficial effects upon the growth of orchids (Yap Chong Bay, 1961). Coconut water also is credited with similar qualities . The terete and semiterete species of Vanda seem to thrive and flower profusely when quantities of fresh cow dung are put in the bed as manure . It is supposed that the various gastric enzymes which might be present in the fresh cow dung , stimulate growth .

After several years trial we have found the following planting methods most suited for epiphytic orchids under conditions in Trivandrum.

1. Specially made earthen spots of different sizes, with plenty of holes at the bottom and sides are used . Neutral media made of charcoal pieces and broken roofing tiles are used for filling the pots.

2. Cut pieces of tree fern stems, as well as three fern root slabs (obtained from the Himalayan region) were found very satisfactory . Cattleyas, Dendrobiums, Vandas, Oncidiums and a variety of other hybrids and species are thriving in both types of planting .

3. Boxes made of teak wood scantlings (1 " x 3/4") and fixed alternately ,leaving plenty of space in the sides and bottom are also good containers for Cattleyas , Dendrobiums , Vandas, Ascocendas etc. The size of the box may be 4" to 9" square and 4" high. Smaller boxes are chosen for smaller plants.

Inorganic fertiliser mixtures containing NPK and the right amount of trace elements with addition of coconut water (20-25 %) is what the senior author has been using very successfully in the last five years in his private garden. Normally a 20 : 20 : 20 (NPK) formula is used every week for 3 sccessive weeks followed by a 10 : 30 : 20 (NPK ) mixture. During the main growing period, just before the commencement of the South -West monsoon , once in three weeks a 30 : 10 : 10 (NPK ) mixture is used . Organic fertilisers are seldom applied . All the chemical mixture have the desired quality of trace elements mixed with them.