April in Your Orchid Collection

Dr. Martin Motes

Epi radicans


Epi radicans

April in your Orchid Collection

April Climate Data
Average high: 83.8
Average low: 67.6
Average mean: 75.7
Average rainfall: 3.36"

Far from the cruelest, April is the kindest month to South Florida orchid growers. The weather in April is definitely settled into warm, even deliciously hot, with passing cold fronts only adding the delight of a pleasant change in temperature. The clean, bright days brimming with abundant sunlight and the low relative humidity create the high drying potential that orchids love. Now we can get our orchids off to a great start on the growing season by practicing our very best watering skills under ideal conditions. Water heavily when you water and allow the plants to dry thoroughly before watering heavily again. Drying 'hard' in the Spring will produce benefits all season. We want to get our plants well launched while leaving all the fungi high and dry.

The new shoots of Oncidinae, grammatophyllums and dendrobiums are quite cup-like; care must be taken that water does not stand too long in these immature growths. Water these types very thoroughly with two or three applications of water spaced 10-15 minutes apart. Water should run freely through the pot on each application. Saturated thoroughly in this fashion the plants will need only weekly watering. Even more care should be taken with the soft plicate leafed genera like Catasetum, Mormodes, Cycnoches, Gongora, Calanthe and Thunia The new growths of this type are rolled together (the fancy word is convolute) like a collapsible drinking cup. These should be grown in water retentive media that should be saturated at each watering to permit the developing roots to have abundant water but allow the vulnerable new growth extra time to dry. Feel the weight of a pot when you have finished watering. Be sure it is heavy with water. If it's not water one more time. With plants properly spaced, good drying should not be difficult in the hot dry air of April. But do be careful to water early enough in the day to allow the tender new growth to throughly dry by twilight.

With vandaceous orchids grown in slatted baskets, most growers find that they dry altogether too well in April. Vandas can be watered almost every morning in April. Indeed, a second light watering or misting in mid-afternoon in April and early May is often beneficial provided the crowns and leaf axils of the plants have time to dry completely by nightfall. Another strategy under high drying conditions is to bend the rules, at least occasionally, and water heavily in mid to late morning . Late waterings on weekend mornings (you didn't want to get up early, any way) provide relief for plants that are more stressed on week days with their owners absent. Very occasionally, one needs to break the rules absolutely and water thoroughly (not just mist) in the mid to late afternoon so the plants can slowly absorb the water across the cool hours of the night. This is the season that one must be sure that Vanda roots have turned overall dark green when we have finished watering. Two applications of water to the point of runoff spaced several minutes apart should accomplish the required color change from white to totally green. Saturated roots are absolutely necessary to provide the plants the moisture the plants need to withstand the heat and dry air typical of April. Sometimes, particularly at this season, the roots will not change color even after the second or third application of water. This lack of response to water is because the roots have become so dry that they are repelling rather than absorbing water. They are behaving like a cork in a wine bottle. The grower must exert special effort to re- saturate the roots. Often this will require 4 or 5 waterings to the point of run off spaced 15 minutes apart. Once the roots have been changed to the healthy overall green, normal applications of water should bring them around in future.

With increased heat and light and the onset of growth, fertilizer becomes more crucially important to the plants. Balanced time release pellets(13-13-13) can still be applied to potted plants provided the duration is 180 days or less. Most time release fertilizer breaks down faster under South Florida conditions and should be exhausted by October when we will want our plants to slow down. The brand marketed at retail as "Dynamite" is generally considered by professionals as superior in reliability to other types. In April, 15-5-15 can be applied to most genera at the rate of 2 tsp. per gal every two weeks. Vandas, ascocendas, Aerides, et al will benefit from a full tablespoon of 15-5-15 weekly during this high energy period. One can also apply high phosphorous 'Bloom Booster' fertilizer once or twice at this time to stimulate them to flower for Mothers' Day or failing that to win those trophies and A.O.S. awards at the Redland International Orchid Festival the next weekend. High phosphorous (we use Millers' Solugrow 8-48-12) also stimulates root action and is important in getting all genera off to a good start on the growing season. This is one of the few times that high phosphorus is perhaps beneficial. During the rest of the year it is to be avoid particularly with our alkaline water. Current science recommends fertilizers lower in nitrogen, much lower in phosphorus and higher in potassium, magnesium and calcium. Peter's Excel 15-5-15 is now the standard for year round use.

The warmth of April, alas, stimulates the growth of bugs as well as plants. Both thrips and mites thrive in the dry heat of April. Liquid dishwashing soap (at 2 oz per gal) will control both but be mindful that soap should not be applied to plants that are suffering from drought stress. Be sure that your plants are well hydrated before you apply soap. Water them extra hard the day before. To be effective soap must be used profusely. The plants should be washed in the solution to the point of wetting every nook and cranny of both the plant and its container. Only such thorough treatment can reach the reclusive thrips and be sure to touch all of the ever prolific mites. A second treatment at 7-10 days is necessary to control mites and a miticide such as Kelthane might be advised. Orthene which is the insecticide of choice for thrips (because of its residual action) is compatible with many miticides. Check with your county agent if in doubt.

The warmth of April, alas, stimulates the growth of bugs as well as plants. Both thrips and mites thrive in the dry heat of April. Liquid dishwashing soap (at 2 oz per gal) will control both but be mindful that soap should not be applied to plants that are suffering from drought stress. Be sure that your plants are well hydrated before you apply soap. Water them extra hard the day before. To be effective soap must be used profusely. The plants should be washed in the solution to the point of wetting every nook and cranny of both the plant and its container. Only such thorough treatment can reach the reclusive thrips and be sure to touch all of the ever prolific mites. A second treatment at 7-10 days is necessary to control mites and a miticide such as Kelthane might be advised. Orthene which is the insecticide of choice for thrips (because of its residual action) is compatible with many miticides. Check with your county agent if in doubt.

April is the classic month to catch up with all the re-potting which you meant to do across the winter. New roots form fast in April; don't rot them off by over-potting or break them off by allowing the plant to wiggle in the pot. Tie them up: tie them down!

April is a month for great moral decisions. When turning on the air conditioner for the first time, consider how much better an orchid grower you would be if you set the thermostat 2 or 3 degrees higher. You will find that you spend more time with your plants when you are accustomed to slightly higher temperatures and it is the master's shadow that makes the plants grow. Besides spending more time enjoying your orchids, when the FPL bill arrives, you can celebrate with some splendid additions to your collection.

April is a great month for naturalizing orchids in the garden. Perhaps its time to think of new homes for some of our burgeoning collection. It's also a great time to establish terete and semi terete vandas and other sun lovers such as reed stem epidendrums.

Vandas, Strap leaf, Terete and Semi-terete: What in a Name?

Although changes in botanical nomenclature can seem a nuisance at times, they mostly give us clues to the true nature of our plants. Two very different genera were "lumped" in Vanda in early literature. The group that we now call Papilionanthe was referred to as "terete vandas" although their culture is quite distinct from "strap leaf" IE (true Vanda). Hybrids between the two genera are also registered as "Vanda" and are referred to as semi-teretes and quarter teretes . Papilionanthe and the semi- terete and quarter terete vandas require very bright light and can(indeed should) be grown in full sun with abundant water and fertilizer(see below). True vandas and Euanthe sanderiana will not survive long under these conditions. In tropical mountains at sufficient altitude "strap leaf" vandas can also take full sun because of the cooler air temperatures and greater cloud cover. Don't try this in "Sunny Florida"

The Culture of Papilionanthe

Papilionanthes are among the easiest of orchids to grow. Many of these tough species even thrive in mangrove swamps, certainly one of the harshest environments on earth. The unusual cylindrical foliage is an evolutionary adaptation to strong light and severe drying conditions. The rounded foliage presents the least leaf surface to the air and thus maximizes the conservation of water. The same structure minimizes the exposure to light as the sun's movement causes light to fall on a constantly changing portion of the leaf. Abundant light, heat and water are the essentials to cultivation of Papilionanthe.

Except when moving them from dense shade to full sun, it is impossible to give these plants too much light. They can be adapted to direct sun in tropical areas (where they are frequently used as landscape material) and can thrive in 12,000 or more foot candles of light. Indeed, strong light is crucial to the flowering of this genus which in nature grows as a vine in small trees and shrubs and like many other vines does not flower until it tops over its host. This fact has led to the observation that Papilionanthe need to sway in the wind in order to flower. This is not quite accurate: what the plants need is to receive light from both sides to initiate spikes. When grown against a post or wall the plants will not flower until they have overtopped their support. Then, they will flower whether mobile or not. Supports for these plants should not exceed one meter, as by that height the plants should be tall enough to flower.

In bright light with good air circulation it is impossible to over-water papilionanthes. During hot dry weather they can be misted or sprayed as often as four to five times a day. In Singapore where they grow to perfection this regimen is provided by nature for much of the year. Elsewhere a hose kept near to the plants makes a grower induced passing shower convenient.

Papilionanthes are scrambling epiphytes that will grow on and in most anything but are happiest with a compost that is water retentive but light and airy. Various mixtures of bark, charcoal, soil, brick and light weight rocks are effective. The easiest, to my mind, because the simplest, is pure cypress mulch straight out of the bag. To any of these mixes should be added a slow release fertilizer. Dry sheep manure is excellent but the new resin coated fertilizers which last for 6-8 months even under sub-tropical conditions are the simplest long term solution. The best currently is the 13-13-13 formula being marketed under the brand name "Dynamite" One application of these in the spring will usually last the growing season and start the break down of the organic material in the media thus continuing the steady fertilizer regime through an entire year. The wiry roots of the plant can be directed toward the medium where they will eventually form a thick mat, and become self sustaining for several more years with only an annual application of low release fertilizer. Papilionanthes will also enjoy a little of whatever liquid fertilizer is being applied to your other orchids, whenever it is applied. They are hungry bears!

When treated properly papilionanthes will grow three feet (one meter) or more per year. They can be top cut annually in late spring or early summer and the cuttings added to the original pot. The stumps will produce one or more off-shoots, thus effectively doubling the stock every year. A good measure of the success of the culture of these plants is the length of the internode of bare stem which appears just above the leaf. Under the best conditions this internode should be ½ inch or more in length (1-1.5 cm.). If it is not, more fertilizer and water can be given. It is frequently stated that these plants require drought stress to bloom but my experience is otherwise: that blooming is determined by day length and strong, well-watered, well-grown plants bloom best.

Few fungus diseases affect these hardy, semi-terrestrials; however, Southern Blight (Sclerotium) can prove disastrous. Should the characteristic web-like mycelium appear, immediate action is required. Drenches of Natriphene and Terrachlor are effective. In severe cases top cuttings can be taken and the old stumps destroyed. Insects, also are seldom a problem; scales and mealy bugs seem only to affect weak plants grown in too much shade. Mites can be a problem in periods of dry weather. The bronze russetting of the stems are the tell-tale sign. Applications of soap (2oz per gal/50cc per 4 liters) or recommended miticides, twice, at a 7-10 day interval, usually is effective.

Although these plants may be a challenge to bloom in the most temperate zones, mastering their culture is amply rewarded with profuse, long-lasting blooms in most tropical and sub-tropical areas. And when cut, their flowers, so reminiscent of gigantic sweet peas, are wonderful in bouquets and centerpieces.

Tasks for April

o Full speed ahead with re-potting
o Water heavily and well
o Don't forget to fertilize
o Spray for mites and thrips

Orchid Events

The fifth annual Fairchild International Orchid Festival will take place Friday March 30, Saturday March 31st and Sunday April 1st. Modeled after the fabulous May Redland Festival, this event will feature 40 growers from around the country and the world.. No other orchid event takes place in such a magnificent setting, made even more so this year by the phantasmagoric Chihuly glass installations. Music and delicious food will make this event truly festive. The admission also allows visitors access to the beautifully landscaped garden, the rain forest and the rare plant house plus all that incredibly diverse , must see glass. An American Orchid Society judged show, sponsored by the Orchid Society of Coral Gables will display some of the latest and finest species and hybrids. The Festival is open from 9:30 to 4:30 PM. Orchid classes and lectures are also scheduled.

April 14th- American Orchid Society Monthly Judging - Montgomery Research Institute of Fairchild Tropical Garden 11935 Old Cutler Rd( just south of the junction of Old Cutler and Red Road, Coral Gables) Saturday March 10th at 12:00 Noon-always an educational experience. The public is invited to bring their finest orchids to be judged or merely to observe the beautiful flowers being evaluated. Ask the Chairman if you can observe a team judging but remember only judges and students should comment during the process.

April 21 and 22 9:30-4:30 Bromeliad Show at Fairchild Tropical Gardens.

Free Orchid Classes

Dr. Martin Motes, one of South Florida's leading orchid experts with over forty-five years of growing experience, will begin teaching the special series of free classes beginning on the week of April 22nd and continuing through May 7th, 2006 at Motes Orchids 25000 SW 162 Ave, Homestead. These classes, part of an ongoing series, cover most aspects of orchid growing in South Florida.

Class Schedule

Saturday April 14- Introduction to Orchid Growing
Sunday April 15- Growing Vandas
ALL Classes at 11:00 AM and lasting about one hour
Motes Orchids will be open to the Public from 10AM to 5PM on days when classes are held

Motes Orchids is located at 25000 SW 162 Ave, that's just south of Coconut Palm Drive (248 St) and SW 162 Ave. Motes Orchids is 2 1/2 miles due east of the Redland Fruit and Spice Park in the heart of the Redland tropical agricultural district. Take Turnpike south to US 1 at exit 12, continue south on US 1 to 248St, then right(west) on 248St to 162 Ave then left(south) one block to Motes Orchids. Call 305 247 4398 or email vandas@mindspring.com for further information.

March In Your Collection