August in Your Orchid Collection
August Climate Data
Average high: 90.6
Average low: 76.5
Average mean: 83.6
Average rainfall: 8.63"
Excerpted from Florida Orchid Growing: Month by Month by Martin Motes. All rights reserved.
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 retain water even from an early morning watering, allowing them to dry a bit harder before the next watering is always a good idea. An extra day of drying rarely does harm.
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 chapter, 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, perhaps not so much as stimulus as shock. One or two heavy applications in succession, a week or so apart will certainly provide all the phosphorus and all the stimulus (or wake up shock) our plants require to bloom.
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.
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July in Your Orchid Collection
July Climate Data
Average high: 90.9
Average low: 76.5
Average mean: 83.7
Average rainfall: 5.79"
Excerpted from Florida Orchid Growing: Month by Month by Martin Motes. All rights reserved.
Although it mostly passes unnoticed to millions locked in their air-conditioned bubbles, July in South Florida is quite different from June. While the pattern of afternoon showers built from the moisture of the morning’s sea breeze persists in July, the thunder-storms are sharper and shorter. The clouds linger less and the foliage dries more quickly. Less quantity of rain falls in July than in June and periods of several days typically pass without a drop. This is good news for orchid growers. July (and August) allow orchidists to focus on the first essential of orchid growing, drying the plant out.
Frequently, neophyte growers ask “What if I go away for several weeks in the summer and there is no one to water the plants?” The response is “That’s wonderful”. Experienced growers use the break in the rainfall during July and August to dry their plants “hard”. Depriving orchids of water for several days until they and the media or baskets they grow in are bone dry is essential to good orchid culture. By drying the plants hard, one deals a severe blow to orchids natural enemy, fungus. Orchids have evolved to withstand drought because fungus can not. During severe drought fungus’ only defense is to cease all growth and retreat into a spore stage. Hopefully (and with good cultural management) these pathogens will not be aroused from this slumber until the first drizzle of September sets in, allowing our plants two months to mature and harden their growth making them less vulnerable to the September conditions which give some advantage again to the fungi.
Careful watering and judicious drying will do more than any other practice to ensure healthy plants. Drought is the orchid plants armor against disease. Be sure that your plants dry as completely as the weather of July permits. Nonetheless, as our plants are in full growth they need adequate water in July therefor after a hard drying, orchid plants need a thorough re-hydration. If the next rain fall is insufficient to saturate pot, roots and media, the grower should add to the natural moisture until he is sure both roots and media are saturated, using two or three applications of water spaced a few minutes apart. When the plants stop dripping is the time to apply the next dose of water. Don’t stop watering until the “heft” of the pot tells you that it is holding as much water as it can. More typically in July, orchidists should use these opportunities when more moisture is required to substitute fertilizer for water and saturate the roots and the media in the same thorough manner. In July typically think of fertilizing rather than watering. Weekly application of a commonly available balanced fertilizer (20-20-20 or 18-18-18) at two teaspoons per gal. will supply the nutrients that our plants require in this period of lush growth. This balanced formula should be alternated every other week with potassium nitrate and Epsom salts (one tablespoon each) to supply the extra magnesium and potassium we now know are plants need on a regular basis. Even better (although not so readily available) lower phosphorus fertilizers containing extra magnesium and calcium with a formula like Peter’s Excel (15-5-15) have been shown to be the precise fertilizer our plants need. This formula is recommended year round. Hopefully such orchid specific fertilizers will become more widely available. Lowering the phosphorus intake of our plants is particularly important in South Florida because of our alkaline water. Always apply fertilizer in the same way as water, in two to three doses spaced a few minutes apart. Apply the fertilizer to the point of “run off” IE.when the solution starts to fall off the plants; stop and move on to the next plant. Repeat the application a few minutes later when the plants stop dripping. In July more than ever, never, never follow the frequently heard and disastrously bad advice of watering before fertilizing. Always substitute fertilizer for water: now and at every season. Roots saturated with water cannot absorb fertilizer but the prolonged wetness can rot your plants. Don’t give fungus the upper hand by wetting the plant’s foliage and roots more often or longer than necessary. Careful watering is especially important throughout the rainy season.
The wise orchidist will have long since finished all of his potting of sympodials and the top working of his vandas but for the rest of us this is the eleventh hour. Autumn is closer than we think and vandas will need at least three months to settle in to their new baskets or pots before the first chill of October tickles their root tips. Unless you can protect them thoroughly from cold, Vandatop cuttings and keikies should not be made after the end of July. If you do take cuttings remember the “3 root rule”. Count down from the crown and make the cutting beneath the third or fourth root. Keep as many leaves as possible on the stump and you will be rewarded with a greater abundance of offshoots. Always slip the sterile knife or shears down between the stem and the leaves and then cut transversely to save as many leaves as possible. Be sure to anchor the cutting firmly in its new lodging. Tie them up and tie them down! There is no time for mistakes in July.
Thrips are much less of a problem in July as the rain tends to wash them away and doubtless there is an abundance of other lush fodder for them elsewhere in our yards. They can reappear in a prolonged patch of dryness, so if you need to think of watering in July it may be dry enough to worry about thrips. A prophylactic spraying for thrips in July will also put a damper on scale crawlers. If a second spraying with soap follows the first by seven to 10 days, the population of mites will be scotched as well.
March in Your Orchid Collection
MARCH CLIMATE DATA
Average high: 80.7
Average low: 64
Average mean: 72.4
Average rainfall: 2.56"
Excerpted from Florida Orchid Growing: Month by Month by Martin Motes. All rights reserved.
Whilst March never comes in like a lion in South Florida, occasionally it slinks in like a bob cat. Frost is not unheard of in the first few days of the month. The more cold sensitive genera, hard cane dendrobiums, phalaenopsis and vandas may well need some protection even into the middle of the month. Overall, however, March brings us some of the most ideal orchid growing conditions of the entire year. Dry air, low humidity and wide swings of day to night temperatures optimize both blooming and rooting of most orchids. In March, Nature gives orchidists growing outside a free sample of what life would be like with a covered green house. With little or no additional water falling from the sky and drying breezes acting like fans, we are in total control of our plants’ water needs. Now, we can water properly: very heavily, and allow the plants to dry thoroughly in the near desert air before the next heavy application of water.
The ideal growing conditions of March present a great opportunity to get our plants off to a superlative start on the new growing season. The virtuous among us, who have already re-potted their cattleyas and other sympodials as they have finished blooming across the winter, can smile serenely, assured of their place in orchid heaven. For us few reprobate it is still not too late to catch up with virtue. In addition to flowered-out plants, now is also the time to replant those genera which are breaking or ready to break their dormancy; i.e. catasetums, mormodes, calanthes and those Himalayan species that have finished flowering. Now is also an excellent time to re-pot those hard cane dendrobiums that need it, with the reminder that they really don’t like to be disturbed and relish their roots being crowded in the pot. For those commercially mass produced plants grown in peat based mixtures, repotting is necessary in any case as the peat mix will not last out the summer and will likely rot all the roots. Hopefully these will have rooted so thoroughly that the roots have formed a solid mass that can be shifted undisturbed to a new only slightly larger pot. Otherwise the roots will need to be washed clean and lightly trimmed. Rock, tree fern, coconut husk, charcoal/wood chip mixes are best replacement media for the long haul. All of these materials have a life expectancy of several years before they break down in South Florida wet humid summers.
Attention to fertilizer in March will pay high dividends later on. As many sympodial orchids are commencing their growth cycle, now is a good time to apply slow release fertilizer to last the season. The 13-13-13, 180 day formula marketed at Home Depot as ‘Dynamite’ (Nutri-cote in commercial sizes) is the best available. Its plastic coating is superior to others and relatively unaffected by heat, an especially important consideration in S. Florida. Applied now it will be exhausted by September when we want to slow our plants down in anticipation of bloom and dormancy. The wide temperature swings of March also maximize the effectiveness of high phosphorous ‘Bloom Booster’ fertilizer. The extra phosphorous in these formulas probably does not really stimulate flowers ( most likely the opposite) but does help rooting. Two applications a week apart will speed the rooting process. Return to regular 15-5-15 fertilizer weekly thereafter as the excess phosphorus in the “Bloom Booster” interferes with minor element absorption to an inordinate degree in our highly alkaline South Florida water.
Vandaceous orchids should be breaking vigorous new roots in March. This is the moment to top them if they have grown too tall and if they have three good roots on the top cutting. Conserving one or more leaves on the old plant’s stump will insure a bountiful production of offshoots. Sliding the knife or shears down the stem before making the horizontal cut usually preserves an extra set of leaves. Now is also the ideal time to remove and reset offshoots of vandas and ascocendas. Again take care each has three or more roots and be sure you tie them firmly in their new container until they have rooted solidly.
March is also the month for acclimatizing sun-loving plants to full sun. Vandas, dendrobiums and reed-stemmed epidendrums that have not been blooming as they should because they are in too deep shade can be gradually moved to more light. This is best done in two or three stages, moving the plants a short distance every few days and always keeping them with the same side orientated towards the sun. Without this gradual acclimatization, The bright clear sunlight of March can scorch even the most sun-loving of orchids.
The chief blot on the otherwise nearly ideal growing scenario of March is thrips. March is the month when we are asked most frequently “Why do my vanda flower spikes grow ½ inch and then die?” The answer, like the answer to so many problems with orchids in South Florida, is thrips. The hot dry weather of March favors thrips which are ubiquitous in our landscapes. The drought of March drives them from their homes in our lawns and shrubberies to seek the cool lush oasis of our orchid collections. Most orchidists recognize the symptoms of thrips on their flowers, :the silvered, sand blasted appearance and the withering of the flower parts. Many do not recognize the earlier symptoms which show up on the root tips of vandas and ascocendas as a pitted ring at the point where the green growing root tip is maturing into white. Left unchecked, this damage will cause the root tip to wither. When it re-starts growth, a brown ring remains. Orthene (acephate)is the chemical of choice for thrips because of its low toxicity and residual action. Knoxout and Malathion are recommended also by the Florida Department of Agriculture. A non-chemical solution is liquid dish soap applied at the rate of 2oz (6tbs) per gallon of water. Be sure to water the plants the day before applying soap and take care to drench the plants thoroughly, covering not only all the surfaces but penetrating into leaf axils and other nooks and crannies where the reclusive thrips loves to loiter. Root the thrips out of your collection and you will get the growing season off to a good start.
December in Your Orchid Collection
Average high: 77.5
Average low: 62.2
Average mean: 69.9
Average rainfall: 2.18"
Excerpted from Florida Orchid Growing: Month by Month by Martin Motes. All rights reserved.
December marks the beginning of the serious dry season in South Florida. While this additional dryness provides relief from the autumnal rains that can bring so many fungal problems, December is also the month of shortest day lengths. This contracted period of light, on the contrary, reduces severely the drying potential for our plants. Nature thus both gives and takes away from us in December. We must make sure, therefore, that we do not aid the dark side of the force by improper watering. In December, above all, one must stick strictly to the two cardinal principles of orchid watering: water early in the day so your plants have as many hours as possible to dry, and water heavily when you water, allowing longer intervals between watering to dry plants thoroughly. This practice maximizes the benefit of the dryer air of December and minimizes the adverse effect of the shorter day lengths.
When nature has delivered a light overnight or early morning rain as she so often does in December at the leading edge of a cold front, add to her efforts by watering thoroughly that same morning and skip out watering for an extra several days afterward. With this method you can use the general dryness of December to give yourself much of the advantage of a greenhouse in terms of controlling watering. As in all aspects of orchid culture, keen observation is the key to success. In cooler weather your plants need much less water. Moreover cool air even at the same relative humidity, strips less water from your plants because cool air has less water holding capability. Always be sure that your plants really need water before you roll out the hose in December. Remember to use at least one of the standard tests for dryness: the finger dug slightly into the media test or the newly sharpened pencil coming dry like a knife from a well cooked custard, or test by hefting a pot that you know the weight of, both wet and dry and be sure that it has attained sufficient lightness. When you are sure they are dry, water them until you are sure they are very wet, then let the drying air of December do its magic to ward off leaf spotting diseases.
Himalayan dendrobiums of the nobile and Callista (D. aggregatum, chrysotoxum, etc.) Sections require no additional water (beyond rain) in December. Remember, those of you who water (or, even worse, fertilize) these dendrobiums in December, will be punished by having your flowers taken away in the Spring. Some growers who have the space, isolate these dendrobiums along with other types that want hard drying such as Catasetum, Cycnoches, Mormodes, and Calanthe. Another strategy is to hang these plants high or at the edges of the collection reminding oneself to neglect them and also to avoid watering them by mistake. Some growers achieve the same result effect by turning the pots of these genera on their side in November or December, to avoid catching water from whatever source. Plants of some of these genera that have finished flowering can even be removed from their pots and stripped to bare roots in anticipation of re-potting them in new media when they break growth in the spring.
Most sympodial orchids are resting in December and require less fertilizer. Biweekly or even monthly applications of a balanced fertilizer or 15-515 are still desirable. Nitrate nitrogen is the most readily absorbed in cooler weather; therefore at least one more application of the potassium nitrate/magnesium sulphate (at 1tbs. each per gal.) recommended in November is still a good idea. It’s good stuff! Vandas, Phalaenopsis and other monopodial orchids should be fertilized right through the winter although both the amount of fertilizer and the frequency of application can be reduced. Remember reddening of the foliage is not natural, nor is it a response to the cold per se but rather a symptom of nutritional deficiency. The plants are asking for more potassium and magnesium. Give them the groceries.
December can be cold. Frost has occurred in the first week of the month and unforgettably, the coldest temperatures ever recorded in South Florida were registered on December 25, 1989. If you haven’t taken some of the precautions outlined in the November Newsletter, get busy! Keep a close eye on the forecasts during this volatile month.
Remember that hard cane dendrobiums of the sections Spathulata and Phalaenanthe are the most sensitive of commonly cultivated orchids. They resent temperature much below 60 degrees F. Phalaenopsis are next most sensitive, then vandas. Protect all these genera more carefully.
If you are getting a jump on Spring potting chores by repotting sympodial orchids that have finished blooming, it is particularly important that you take extra care in securing them in their containers. These plants may not be sending out new roots for several months, enough time for them to be shaken loose from insufficient staking. Passing cold fronts can bring brisk winds in December. When new roots start to form on insufficiently secured plants, wind moves the plant and chafes the new root tips off. Improperly secured plants are never able to root properly and slowly pine away. If you love them you must tie them up, tie them down. This is also especially true of mass produced orchids sold in Home Depot, K Mart etc. The soft, peat based media used to grow these commercially produced plants in the controlled environment of a greenhouse often does not provide sufficient purchase to secure the plants in the rough and tumble of a South Florida orchid collection buffeted by harsh winter winds. You probably should have already re-potted these into more durable medium but until you do, tie ‘em up!
Keep those vandas, phalaenopsis and hard cane dendrobiums as warm as you can. Merry Christmas, Hanukkah, and Kwanza!