Ascda. Elizabeth Taylor
| July and August are the two most similar months in South Florida.
Most of the advice on watering, disease and pest control in last month's
calendar still apply but subtle changes are taking place. Although it may not
seem so, as temperatures climb into the low nineties most afternoons, summer is
in retreat: each day a little shorter, each night a little longer. With shorter
days the importance of watering as early in the morning as possible comes to
the fore. With less hours of sunlight to dry the plants, extra care should be
taken in choosing when to water. Back to the basics of the classic saying : If
a Vanda looks like it needs water, water it; If a cattleya or oncidium looks
like it needs water, water it tomorrow. If a Paph or a phal looks like it needs
water- you should have watered it yesterday. If plants are still wet even from
an early morning watering, allowing them to dry a bit harder before the next
watering is always a good idea. August should provide numerous opportunities to dry each orchid to its desired level of dryness. Take the opportunity to dry your orchids "hard" at least once but preferably twice in August. This will give your orchids a leg up on their mortal enemies, the fungus, before the drizzle of September switches the advantage to our adversaries. August is definitely not the month to over indulge in water. September, the soggiest of months, is next up. The corollary to this calculated drying is the concept that when watering in August above all water thoroughly. If watering is necessary be sure that the roots and medium are totally saturated with the application. The drizzling rains of September are so detrimental precisely because they keep the foliage of the plants wet unduly long. We want our plants which are still growing to receive plenty of water but also plenty of drying time. Good air circulation and proper watering are the keys to disease prevention. Remember that your plants will have increased considerably in size by this point in the growing season. They have added extra growths and extra leaves across the summer. August is a good time to evaluate the spacing of our plants. Remember the old Florida saw that one needs a cat to grow good orchids because when properly spaced a cat should be able to navigate the benches between plants without knocking them over. While we can not recommend specific chemicals, the county agent recommends Banrot, a convenient combination of Thiophanate-methyl and Truban which controls a number of leaf-spotting diseases and soft rots, for home owner use. A combination of Thiophanate- methyl and mancozeb has also been recommended. This can be found pre-packaged as Duosan. If one can over come the aversion to chemicals and can learn the safe application of them, they are valuable tools to better orchid growing. An ounce of prevention is worth a pound of cure especially before the soft, slow drizzle of September sets in. Lengthening nights in August mean cooler nighttime temperatures. Many sympodial orchids are reaching the end of their growing cycle and require less nitrogen. Cattleyas and oncidiums have maturing bulbs. Genera that become deciduous in winter like nobile dendrobiums, calanthes and catasetums should be given much less nitrogen in August to prevent them producing an unwanted off season growth and perhaps forgetting to flower. Substitute an additional application of potassium nitrate and Epsom salt (1TBS each per gal) instead of the balanced 20-20-20. Vandas will respond well to this also, as several of the parental species of our hybrids produce blooms on shortening day lengths and lower levels of nitrogen in their fertilizer seems to egg them on. As explicated in the last newsletter, modern research indicates that orchids require less phosphorous than previously thought. This concept should lead us to more judicious use of phosphorus. Fertilizer high in phosphorus may still be of some value at the end of the growing season. One or two heavy applications in succession, a week or so apart will certainly provide all the phosphorus and all the stimulus our plants require. Snails can be somewhat of a problem in August too, but left to multiply they will be in their full glory when those slow unrelenting rains of September set in. Control them with baits in pellet or liquid/paste form. Remember, these are baits, the pests are drawn to them. Therefore apply lightly, but frequently. Because they wash away in the heavy rains, baits should be reapplied every two weeks. One pellet every two to three feet will do the job, but one application will not. Given a choice, the smallest pellets baits are best. They keep us from over applying and also pose much less threat to neighborhood pets. A small bait in a Vanda crown is a nuisance , a large bait can be a disaster. If you have been waiting to make cuttings of the terete vandas or reed stem epidendrums, you can wait no longer. The potting season is drawing absolutely to a close. Pot up those overgrown phals before they even think of spiking. Re-set those strap leaf vandas early in August whilst they still have just enough time to re-establish themselves in the September humidity and before the cool weather arrives and their root growth slows or stops. As in all seasons be sure that the plants are firmly set in their containers. There is no "wiggle room" this late in the growing season to restart tender roots that have been chafed off a loosely set plant. As the cooler weather approaches try to give plants that have been repotted late more protection from the first cold snaps. WateringProper watering is easily the single most important aspect of orchid growing. Neophyte orchid growers most frequent question is " How often do I water this plant?" In a very significant sense this is exactly the wrong question. A more illuminating query would be "How much does this orchid need to dry out?" Epiphytic orchid are more like cactus than any other type of plant. Like cactus, orchids are locked in an evolutionary struggle with their mortal enemies: fungus. This battle is why orchids took to the trees, rocks and other generally harsh environments that they inhabit in nature. These desert-like environments allow orchids to dry out quickly and thoroughly. Fungus can not survive sharp drying: therefor drought is the epiphytic orchid''s best friend. Each orchid species has developed organs for water storage that permit the plants to withstand drying that would be fatal to most other plants and that is totally intolerable to fungi. This evolutionary strategy allows orchids, small, slow growers as plants go, to thrive in situations where few other plants could survive much less prosper.Knowing the tolerance for drought of various types of orchids is the most essential knowledge that orchid growers can have. Orchids are the largest and most diverse group of flowering plants. Each genus has developed its own techniques of coping with drying and each genus and species must be treated differently in order to maximize success. The focus of the grower''s attention should be on the degree of drying that a particular genus requires. The standard advice is always to err on the dry side. This advice is particularly cogent in the torrential rains of a typical South Florida summer. When a break in the rains gives us an opportunity to dry our plants, we must take it. Fortunately, July and August frequently afford us these not to be missed opportunities. The ubiquitous and affordable Phalaenopsis , which is frequently the beginner''s first orchid, appears at first glance an exception to the rule of drying. They are in fact the exception that proves the rule. Although frequently compared to African violets as plants who require constant moisture , phalaenopsis nonetheless require the slight but significant drying of their roots which is provided by the large air spaces in the open but moisture retentive media that are typically used to grow them. This need for air at their roots is critical. When the air spaces in the medium are filled with water for too long the roots can not dry and they rapidly rot. This phenomenon is why phalaenopsis in most media perish so quicky when novices attempt to grow them outside in our wet summers. The same fate awaits phalaenopsis grown in sphagnum moss under cover if the moss is not changed annually. As the sphagnum breaks down the air spaces provided by the fine hairs of the moss collapse leaving the orchid's roots to rot in a wet mass without sufficient air to permit the roots to dry as they require. Cattleyas, dendrobiums, oncidiums and other types with heavy bulbs require abundant moisture during the growing season but need to dry out thoroughly between waterings. In a typical South Florida summer these plants rarely require much additional water. That said; they also should not be deprived of essential water or nutrients during this period of active growth. When these plants have not received a good rain in three or four days, the grower has an excellent opportunity to fertilize them with liquid fertilizer. Always substitute the liquid fertilizer for water. Never follow the bad advice of watering before fertilizing, a receipt for fungal problems particularly here in South Florida. Many successful growers actually tolerate a few weeds in their pots of sympodial orchids as indicator plants. When the broad leaved herbs are wilting, its time to think of watering. Remember, again, that nowhere is it more true than in S. Florida that "When a Cattleya looks like it needs water, water it tomorrow!" Vandas, which relish watering on most days, also need to dry out. The universal rule of Vanda watering states that when Vanda roots are white, they are dry and should be watered until they turn overall dark green. When they turn white again the process should be repeated in 12 to 24 hours. While this rule holds regardless of relative humidity, temperature, air movement or light intensity, the exception is during periods of prolonged heavy rains such as are typical of South Florida summers. Here in the rainy season vandas too benefit from an occasional hard drying. Three or four days without water relieves the vandas from much of the pressure from fungus which is more or less a constant in our summers. Vanda roots that have been dried hard will need to be re-hydrated with several applications of water spaced a few minutes apart. Most frequently nature takes care of this detail for us and then some with the next major thunder storm whose rains will wash over the Vanda roots for a solid half hour! Remember also, that during the summer in particular vandas are heavy feeders. They will appreciate the substitution of liquid fertilizer for water on most of the occasional breaks in the rain which require us to water. Keeping all these cautions in mind will gird up our orchids for the onslaught of September's rains. Get up early to enjoy the last of the night's chill and think about the vegetable and herbs you'll soon be growing. The farmers of South Dade are already preparing their fields. We consider September 1st a good date for the first planting of arugula! Dr. Motes regrets that he cannot respond to all specific questions and problems; both time constraints and the difficulty of diagnosing at a distance and through a computer make it awkward. Orchid EventsAmerican 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 August 12th 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!For those longing for an orchid show, the only summer show in Florida, the Platinum Coast Show takes place August 18-20 at the Cocoa Expo Sports Center. 500 Friday Rd Cocoa, Fl.. Contact Glenda Titler (321) 637-0948 or titlerpandg@aol.com for more info. Memorial Service A celebration of the life of Bert Pressman, a pillar of the orchid community of South Florida, will take place on Friday August 11th at Fairchild Gardens. Come at 4:30 to remember Bert who made some much of the orchid life of South Florida glow. Motes Orchids is located at 25000 SW 162 Ave, that's just south of Coconut Palm Drive (248 St) and SW 162 Ave. Both Motes Orchids and Knaus are 21/2 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(Caribbean Dr in Cutler Ridge), 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. |