March in Your Orchid Collection 2025
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.
February in Your Orchid Collection 2025
FEBRUARY CLIMATE DATA
Average high: 77.7
Average low: 60.7
Average mean: 69.1
Average rainfall: 2.07"
Excerpted from Florida Orchid Growing: Month by Month by Martin Motes. All rights reserved.
Despite the bloom on the avocados and the burgeoning new leaves on the live oaks, February is not spring in South Florida. Danger of freeze continues past mid month and frost can occur still into March. Even if the weather is balmy it’s too early to let down our guard or take down any protection we have mounted against the cold. The trend however is toward the positive as each lengthening day brings extra hours of warming sunshine to begin waking our plants from their long winter’s rest.
February characteristically brings a wide swing of day to night temperatures, ideal for spiking ascocendas and vandas but also wringing from the air heavy dews and dense fog. Whilst these add a romantic atmosphere to the South Florida landscape, Wuthering Heights is singularly devoid of snails and slugs (much less Botrytis). The silvery carpet of dew provides a silky path to our orchids for snails and slugs which can range far, under these favorable conditions. They are eager to make a nice meal of your Phalaenopsis leaves or the soft crowns of your vandas before they retire during the dry months of March and April only to dream of the fresh shoots of the sympodial orchids brought forth by the first rains of May. Now is the time to give them a rude awakening. Remember that snail bait is most effectively applied lightly (scatter the pellets every few feet) and frequently (every 7 to 10 days). Two or three applications should do the job.
The heavy fog which can cause condensation on leaves even under cover can also bring trouble. Botrytis is a fungus disease that can disfigure flowers with small black spots. Particularly apparent and annoying on white Phalaenopsis, Botrytis can ruin other flowers as well. Control is typically achieved in commercial greenhouses with fungicide in aerosol forms and by running fans to prevent condensation on the flowers. The latter option is also available to collectors. A small fan turned on the spiking and opened flowers at night will greatly alleviate the pressure of Botrytis. So will, to a degree, the application of soap which we suggested in January to control mites. Bicarbonate of soda, ordinary baking soda, at 1Tbs. per gal will help as well. Quaternary ammonium compounds (Physan, RD40, Consan, pool algicide) also give some control. Maintaining long lasting flowers like Phalaenopsis, dendrobiums and bi-foliate cattleyas in more perfect condition is well worth the effort. Having waited so long for the flowers we want to enjoy them as long as possible and they do all last longer in cool weather.
The lower overall temperatures of February call for less frequent and lighter applications of fertilizer as was the practice in January. If any reddening of the foliage persists another application of Epsom salts (1Tbs per gal), preferably in combination with Potassium nitrate, is called for; Nitrate nitrogen being more available to the plants under cooler conditions. If your resolve holds steady not to water (or above all) fertilize those Himalayan dendrobiums, your reward may shortly become evident in bursting flower spikes.
Like the avocados and the live oaks, many cattleyas and other sympodial orchids have bloomed and are just commencing new growth in February. Right after flowering is usually an excellent time for repotting from the plant’s perspective and the cool day time temperatures in the greenhouse are hospitable to the orchid grower as well. It’s still a bit early to re-basket vandas But an early start on the cattleyas will allow plenty of time and energy for those Spring chores which are right around the corner. With that thought setting out to secure a good supply of pots in anticipation of the potting season ahead is on February’s agenda.
Click here to purchase the new, updated, second edition of Florida Orchid Growing: Month by Month.
January in Your Orchid Collection 2025
Average high: 76.5
Average low: 59.6
Average mean: 68.1
Average rainfall: 1.88"
Excerpted from Florida Orchid Growing: Month by Month by Martin Motes. All rights reserved.
January is somewhat like December but in reverse, with each succeeding day bringing longer hours of sunlight until days are long enough that afternoons return at the end of the month bringing extra sunshine to warm us after the extra sharp cold snaps. January, like December, is cold and dry, in fact even colder and drier. Dry is good, cold can be very bad. We need to accentuate the positive by especially careful watering in January. By keeping our plants as dry as possible and spacing our waterings as far apart as possible, we conserve our potential to use water to protect our plants from the cold, keeping our powder dry, as it were. In January water early, water thoroughly when you do and do so sparingly. The cooler overall temperatures of January are much less dehydrating even to plants which have received less water. remember, many of our orchids come from seasonally dry and cool climates not so different from South Florida. Many orchids are equipped to handle the drier cooler conditions of our January. A good strategy is to “top-up” the light watering that our plants receive with the passing showers that each successive cold front brings. This slight additional irrigation may prove to be all the watering that many genera need. Such parsimony, preserves the possibility of using water on truly cold nights to warm our plants.
Water is the only feasible source of heat available to plants grown in the open, under trees, in shade houses or on patios in South Florida. Ground water here (and in most of the rest of the world is about 63 F. (16C). Water out of municipal systems is not far different. On truly cold nights turning on the water can be of great benefit to our plants, provided that they have not been over-watered in the days and weeks preceding, thus inviting the ever present fungi to do more damage than the cold. For this reason as well, in general, orchids are better off dry until temperatures approach frost or freezing. The logic for maintaining plants dry is not only to minimize fungal problems but also because cold air is typically very dry air. If plants are wet in very dry and rapidly moving air say 10 or more MPH, evaporative cooling can take place, chilling our orchids further and faster than they would if dry. When the water goes on it needs to be in heavy volume and it needs to stay on to keep the plants thoroughly bathed in its warmth. Very still air on the other hand, presents a different danger as frost is possible at temperatures higher than is commonly realized. In calm air frost can form at higher elevations and settle in on plants while the surface temperature is only in the upper 30's. The best forecast for nights when the temperature will hover near 40 is a light wind of 2-5 miles per hour. This light wind mixes the warm air near the surface and draws warm from the earth. Clear, cloudless, still nights with bright shining stars elevate the spirit but harbingers frost.
Forecasts of temperatures below 40 F should stimulate us to action.
If it is not practical to bring all the Phalaenopsis, vandas and hard cane dendrobiums into the house or garage, think of using water to help protect them. Shade cloth or even patio screen hold in a surprising amount of heat like an lacy Mantilla. Under screen, a fine mist head attached to a hose and left running beneath the bench or plant rack will provide several degrees of additional warmth that will often sufficiently temper the chill and ward of any light frost settling in. Growers with swimming pools frequently turn on the recirculating pump to keep a supply of warm water near the pool’s surface where it can add heat to the ambient environment. A few degrees of warmth frequently makes all the difference to our sensitive orchids. In more open areas not protected by a permanent irrigation system, an oscillating sprinkler at the end of a garden hose is very effective. These are readily available at Home Depot and garden shops for a few dollars. On frosty nights, start the water at bedtime and let it run until the sun is up. The extra water once or twice in a month will do no harm to orchids that have been properly and judiciously watered the remainder of the month. In fact, these occasions present the opportunity to be sure that excess fertilizer salts have been leached from the pots and medium. A good work can be born of necessity!
Remember that Himalayan dendrobiums and ‘‘warm growing’’ Cymbidium hybrids will positively relish temperatures down to 32F and a light frost is just the ticket for great bloom. Keep the water off these!
In the drought of January, mites, which affect nearly all genera of orchids, continue to be a serious problem that will only get worse. They will reach a crescendo in March and April but January is a good time to scotch them. Paphiopedilum and other softy leaved genera are particularly susceptible but no genus is free of them. One theory on why deciduous genera such as Catasetum, Calanthe and others lose their leaves hypothesizes that this totally rids them of mites.
Being totally rid of mites is a good thing! Sometimes this is easier said than done because mites reproduce with such voluminous speed. Their life cycle from egg to reproductive adult being is as short as twelve days. In order to control mites one must achieve as total a kill of the population as possible. Total control can only be achieved with two successive sprays. After spraying for mites initially, one must spray again in 7 — 10 days. No single spray is totally effective in killing both adults and eggs and a second spraying is necessary to kill any survivors before they can reproduce. Oil as recommended in the December chapter at 1.5 oz per gal followed in7-10 days by soap at the rate of 2 oz per gallon is very effective. These treatments are also quite effective against scale and mealy bugs which thrive on drought as well. Be sure your plants are well watered the day before applying both oil and soap and be sure that you cover thoroughly all leaf surfaces especially the lower ones which are mites favorite hide outs.
For those who wish to be more aggressive, the University of Florida IFAS recommended chemicals for mite control are:
Avid 0.15 EC
Kelthane T/O
Mavarik Aquaflow
Talstar Flowable
Always follow label instructions for use. Any of the can be alternated with the soap or the oil in the 7-10 day cycle.
Controlling mites pays huge dividends! You’ll be surprised at the extra vigor your plants display.
Cold Watch
As cold is a major theme of this month, a review of some factors effecting temperatures in South Florida should be particularly valuable to new comers in the wide world of orchid growing.
While we bask in the warm glow of a tourist board’s vision of winter, (made all the warmer by thoughts of our envious friends and relatives stuck in the northern snow and ice) we should be mindful that January can produce quite severe cold. The majority of hard freezes in Florida take place in January, and even short of that catastrophe, the month usually brings the coldest weather of the year. We need to keep a sharp eye on the weather reports while remembering that in our almost island of Florida a number of factors influence the severity of the cold which will impact us.
First the shape of the cold front interacting with the shape of the peninsula. The weather that delights the tourist board and all of us while plunging most of the US into the throes of ice and snow usually result from particularly large, slow-moving masses of cold air that have spread across much of the continent before reaching Florida. Large broad masses of cold air that seep downward over a broad front also cover the Gulf of Mexico and the Atlantic as they progress southward. These tempering bodies of water bathe the cold to merely refreshingly brisk temperatures. More dangerous to our plants are the smaller, tighter, fast-moving fronts which plunge like a dagger of cold straight down the peninsula to the tropical heart of South Florida. Such fronts typically spawn the freezes and severe plant-damaging cold that is of the greatest concern to orchidists and other plant people. These Siberian Express fronts bring winds out of the Northwest that are un-influenced by the benign, protective bodies of water flanking the peninsula as they drive down the central landmass of Florida. When the winds from an approaching front start out from the southwest and move gradually to the northwest and then quickly to the north and northeast, we can expect cold nights and warm days that reasonably well-protected orchids not only tolerate but in some case actually relish. The more savage fast moving fronts where winds start in the Northwest and stay there are the ones to send us thinking of moving plants or providing additional heat.
Wind direction is always critical in South Florida. Because of the peninsula’s decided eastward cant, winds from the north in much of South Florida are in fact relatively mild. North winds here are blowing across the warm Gulf Stream. The first shift to the northeast absolutely spells relief as the warm Atlantic has absorbed the cold.
Wind speed is also important. Strong winds at low temperatures chill our plants more rapidly, exposing them to additional hours of chilling. “Wind chill factor” has no relevance to plants until the actual air temperature drops to a level unacceptable to the plant. After that, the more rapidly the plant itself’s temperature falls to that damaging level and the longer it stays there the worse the case. Wind speed enters the equation only if the final low temperature is below our plants’ tolerance. Wind breaks of vegetation or manmade are always to be sought. Native epiphytic orchids hide out in the most protected hammocks and sloughs. We can learn from them.
Dead, still air looms with another threat: radiational cooling which can allow frost generated at higher levels of the atmosphere to settle in on our plants even when the air at the surface is only in the upper 30's. These frosts typically occur when the front has passed leaving such low humidity that there is no moisture in the air to retain ground heat which radiates quickly into the cold reaches of space. Light winds of 2-5 miles an hour are our friends on these nights. They stir additional heat from the ground and keep the colder upper air from settling in.
Relative humidity also has a profound effect on temperatures. Dry, clear air allows heat to radiate out into space. Those bright starry nights are beautiful but as Good King Wenceslas knew they are not necessarily our comforters. The best measure of the dryness of the air relative to cold is the dew point. When water vapor is wrung from the air an incredible amount of energy is released and the heat of transformation raises the air temperature a degree or two. Because of this phenomenon, the dew point is usually the closest measure of the coldest temperature that will be reached in the night. Particularly on still clear nights it should be monitored closely.
Wind direction, wind speed, dew point — where does one find these on a chilly night? At the Florida Agricultural Weather Network (FAWN), a system of automated weather monitoring stations, as close as your computer. There will be a station near you. There are also several at points north of the nearest location that give data on conditions that are effecting areas through which the cold front is moving toward us. FAWN is updated every 15 minutes here. Bookmark it for something other than worrying to do on those cold nights
December in Your Orchid Collection 2024
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!