Most of us who grow orchids have inherited the traditional approach: "Everything for the blooms, and to blazes with the plants!" Actually, if we gave our attention to the plants, the flowers would take care of themselves and be more spectacular to boot.

This we have learned to do in the preceding few chap ters. But we also can do more; we can give orchids that extra little fillip that lifts them out of mediocrity. You wouldn't think of growing carnations at their best without incorporating into the soil any additional nutritional elements they require. You should do no less for orchids. Both science and casual practice have demonstrated the desirability of feeding orchids.

But how should we feed the orchid plants? There is the dilemma. There is no exact technique for giving them supplemental mineral food in the form of liquid fertilizers or chemical salts, for practical science until lately has largely ignored orchid culture, although there is not a horticultural field with more urgent and fascinating problems. Someday we may know the answers, but at the moment, feeding orchid plants is a compromise between time-honored misconceptions, traditional methods, conflicting opinions of growers, brash attempts of amateurs, and the exploratory gestures of a few scientists.

The original attempts eighty years ago to feed epiphytic orchids with manure water—so good for most garden potted plants—ended in a few spectacular successes and many failures. Plants grew luxuriantly for a week or two, then gradually died; their roots were rotted off. These abortive experiments strengthened the notion that orchids could not be fed. The experiments were unfortunate in that they were poorly conceived and badly carried out. There was no practical understanding, then, of the close correlation existing between plants, their roots, their composts, and temperature and sunlight. Actually, the effect of manure water on epiphytic orchids was calamitous because the early growers kept their plants heavily shaded. This was entirely wrong. The more you feed a plant, the more sunlight you must give it. Another reason for their failure was that, unlike soil composts, osmunda does not buffer the caustic action of manure water. Also, the thrifty dietary habits of epiphytes made them allergic to foods which were too rich or too strong.

The fact that early growers tried to feed epiphytes indicates that they realized that orchids grown in osmunda were half starved. Success in feeding epiphytes has come about through the discovery of nontoxic nutrient solutions, and application of the rule that a little food given regularly is better than a lot supplied occasionally. Weak—very weak—solutions of manure water, fish meal, and guano have been beneficial when applied regularly and interspersed with normal watering. Plain water washes out the accumulated salt crystals that may burn orchid roots. The outstanding success, though, has been with nutrient solutions—water culture solutions, if you wish to call them that. Nutrient solutions are safe, are self-buffered, are not concentrated, are as balanced as fertilizer combinations can possibly be, and ordinarily do not leave toxic salt residues. They can be used continuously both to water and to feed orchids.

On the other hand, there has been no disagreement about feeding terrestrial orchids. The value of adding organic fertilizers to composts in which terrestrial orchids are grown has been recognized for many years. The sole danger is in overfeeding—using too much or too strong manures. Many modern growers, for that reason, have given up using manures. They feel that orchids in manured composts grow too rapidly, developing weak, non-blooming growths. There again is the catastrophic combination of too much food and too little sunlight. A few growers have added small amounts of cottonseed meal or bone meal to their terrestrial orchid composts. These organic fertilizers are safe, yes, but will they repay the labor and expense? No one knows with any certainty.

It would be easy to quote from published texts, scientific pamphlets, and acceptable amateur results, and let you take your pick. But the little variations which are so often recommended would be confusing. It is best to reduce feeding orchids to a bare minimum based on exact facts and accurate measurements.

Horticulturally, there are few plant foods better than animal manures. There are, however, sound reasons for avoiding the use of manures. They must be old and it is difficult to know the correct stage of decomposition. The correct amount to mix with composts is debatable. Manures decompose osmunda rapidly. So stay away from animal manures, at least temporarily, until you become somewhat expert and want to experiment.

Another standard organic food not recommended for orchids is bone meal. As bone meal decomposes it produces an alkaline reaction which prevents orchid roots from obtaining their food. The key to orchid nutrition is in keeping the compost on the acid side.

If you must try an organic fertilizer in a terrestrial orchid compost, use cottonseed meal. After you have blended thoroughly the leafmold and gravel, add a heaping tea-spoonful of cottonseed meal for each eight-inch pot of compost. Mix it in so well that the yellow color of the meal disappears. As the meal breaks down it retains its acid reaction; food is released slowly in amounts suitable for orchids. Unfortunately, cottonseed meal is not as well balanced as it should be for orchids, but it does keep your labor down to a minimum. With it additional food becomes a matter of whether you have the time and inclination to supply it.

The best approach to feeding either terrestrial or epiphytic orchids is through the use of liquid fertilizers; you have three choices: manure water, commercial concentrates, and nutrient solutions. While manure water is the most dangerous it is the most commonly used. Get a wide-mouthed gallon jar, and in the bottom place two cupfuls of ground manure. Fill the bottle with tap water and let it stand for a week or two until the water is coffee-colored. This is the "stock solution." It is too strong to use and must be diluted. Put one-fourth cup of the stock solution in a quart pitcher and fill with water. The color of the solution, when suitably diluted, will be that of very weak tea.

Just enough of the diluted manure water is poured on the osmunda, at the edge of the pot, to moisten it evenly and well. Never let the dilution touch the rhizomes, pseudobulbs, or foliage of orchids—it burns. If it does touch the foliage, syringe it off with clear water. More manure water—enough to saturate—can be used on terrestrials planted in leafmold. Don't use manure water more than once a month, and ordinarily, don't use it twice in succession—flush the pots with plain water when the next watering is due.

Commercial liquid fertilizers are convenient, often odorless, easy to store, and simple to use. They can be applied freely to terrestrial orchids and moderately to epiphytes. They should be used with care, for they too may burn orchid foliage. Their greatest danger is in the high concentration of nitrogen salts they contain. For this reason they must be diluted well. If the solution used is too strong, the excess nitrogen will boost the growth of orchids so rapidly that the pseudobulbs will be soft and may not flower. A teaspoon of the concentrated liquid to a quart of tap water is about right if it is called a "10-10-8" fertilizer. Otherwise, to be safe, make your dilution half the strength of the weakest recommended on the directions. Such dilutions are usually treated with phosphoric acid—two or three drops per quart. This acidifies the dilution and increases the phosphorus, which orchids need. Applications of liquid fertilizers are always alternated with plain water to minimize the injurious effects which residual salts may have on orchid roots.

Nutrient solutions are excellent fertilizers. Gardening textbooks list nearly twenty solutions, most of which may be used on orchids. Some good ones are offered commercially as packaged chemicals which you dissolve in water. All that is necessary is to follow the manufacturer's directions. You will be surprised how little fuss or muss there is.

If you like to experiment, you can make your own nutrient solution. The cost will run about a dollar, the time about five minutes, and the supply will last for months. The most successful nutrient solution at present—at least for orchids—appears to be the one developed by Dr. D. R. Hoagland of the University of California at Berkeley. It may have no merit over others as far as general plants are concerned, but its combination of mineral salts seems to be better for orchids.

To make Dr. Hoagland's nutrient solution it is necessary first to prepare stock solutions in pint bottles from the chemicals listed in the following table:

Stock Solutions For Hoagland's Nutrient Solution (Modified)

Go to a garden store and buy a pound each of the chemicals listed in the table. You may have to get the potassium phosphate and magnesium sul£ate from a chemical supply store. Do not buy chemically pure salts: they are expensive and don't contain some of the rarer mine«·ls which plants require and which are present as impurities in technical and fertilizer salts.

Have ready four one-pint stoppered bottles. In each put one of the chemicals in the amounts given in the preceding table. Then fill the bottles with tap water. Don't mix the chemicals; dissolve each separately in its own bottle. Label each bottle with the name of the chemical it contains. These four bottles hold your concentrated stock solutions. To make a feeding solution add the amounts of stock solutions shown in the following table to one gallon of tap water. CAUTION: Add the amounts of stock solution in the order shown; otherwise some of the salts may be precipitated.

Feeding Solution: Hoagland's Nutrient Solution (Modified)

The diluted nutrient solution may be applied directly to orchid pots. It can be used each time you water the plants, or interspersed with regular waterings.

A simpler nutrient solution using only three chemicals can be made from a formula originated in 1915 by J. W. Shive of the New Jersey Agricultural Station. Make stock solutions in pint bottles as before.

Stock Solutions For Shive's Nutrient Solution (Modified)

Salt                                                                  Level Teaspoons
Potassium acid phosphate                                 1¾
Calcium nitrate                                                  ¾
Magnesium sulfate (Epsom salts)                       31/2

To make the feeding solution dissolve the following amounts of the stock solutions in one gallon of tap water.

Feeding Solution: Shive's Nutrient Solution (Modified)

It may be interesting to try an old, simple formula devised by Norman C. Cookson for English orchidists just after the beginning of the present century. It has simplicity and nontoxicity to recommend it, but it is not well balanced. The nitrogen content is too high. As a result it can be used safely only in good growing weather from late spring to early fall. The quantities of chemicals shown in the following table are dissolved in three gallons of tap water.

Cookson's Formula

Both chemicals are dissolved in the same water container—not in separate ones—to make a stock solution. When ready to feed your orchids add 1 ounce of the stock solution to 1 gallon of tap water, and acidify the dilution with 12 to 14 drops of phosphoric acid. Nutrient solutions also should be alternated with regular watering.

When and how often can you apply any of these liquid fertilizers to orchids? Normal garden practice holds good: Feed lightly and regularly during the warm days of the growing season. Twice a month is often enough to start with; once a month or less often in winter.

In the last analysis, it must be said that feeding orchids is generally good but perhaps not always desirable. A leaf-mold compost as it settles and decomposes provides a small amount of food. So does osmunda, although on a much lesser scale. The fact that orchids have been grown in composts without additional organic or mineral food for many years indicates that success in orchid culture does not come from a planned program of feeding alone.

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