July in Your Orchid Collection

by Motes Orchids in


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, Vanda top 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.


June in Your Orchid Collection

by Motes Orchids in


June Climate Data

  • Average high: 89.5
  • Average low: 75.2
  • Average mean: 82.4
  • Average rainfall: 9.54"

Excerpted from Florida Orchid Growing: Month by Month by Martin Motes. All rights reserved.

            June is the most dramatically tropical month in South Florida. As the southeast Trade Winds blow cool moist air off the Gulf Stream daily, as surely the heating effect of the center of the peninsula percolates up massive thunder heads. The increased cloud cover drawing a veil across the afternoon sun provides much cooling relief for our plants late in the day. Because of this additional cloud cover, our plants are less stressed than in the brightest of May sunshine. The increased humidity makes June feel hotter to us, but this humidity brings blessed balm to our plants from the unrelentingly dry heat of late spring. The shading clouds are also the harbinger of the almost daily rains that arrive like clockwork with the thunderstorms that re-circulate the moisture laden air back toward the ocean in the afternoon. These showers can drop the temperature 10-12 degrees in almost no time, again bring our plants relief when they need it most in the peak heat of the day. In June, such soaking rains that can sometimes be an inch or more an hour, are the norm rather than the exception. For orchids grown outside in South Florida this month, how to dry them out becomes more the question than how or when to water them. For most sympodial genera (cattleyas, dendrobiums, oncidiums, etc.) the natural rainfall of June is sufficient. Only in those rare once or twice times during June when no rain falls for nearly a week is it necessary to think of watering sympodial orchids in June. Even then it usually is a thought that can be dismissed. A thorough, “hard” drying in this first month of the rainy season is usually of much more overall value to sympodial orchids than the slight extra push of additional water. Harder plants that have not been pushed with extra water are much more disease resistant than softer more lushly grown orchids. Vandas and other high water requirement plants may still need periodic watering in June but remember that these types too relish occasional “hard” drying and the heavy often lingering, rains of June are just the nostrum for re-hydrating them even when they have become as dry as the cork in a wine bottle dry. When watering in June, remember at no season is the standard ‘water early in the day’ rule more relevant; those extra hours of drying are crucial. If your vandas or other orchids really need water, water early in the morning to allow time for them to dry not merely by night but by the time the all too likely afternoon thunderstorms arrive to soak them again. Be sure when you water that the roots of the vandas are saturated until they turn overall dark green. This will still take two applications of water spaced a few minutes apart. June is the archetypical month for careful but totally thorough watering. For those of us committed to sloth, this month is one in which benign neglect becomes a virtue.

            With an eye to efficient drying which the season demands, June is an excellent time to review the spacing of our plants. Always give your plants sufficient space to allow for good air circulation to permit rapid drying. Crowded plants stay wetter longer encouraging fungus and bacteria. Scale and mealy bugs also thrive on the soft lush growth generated by overcrowded, overshadowed plants. Mites too love the extra protection from dislodging rain that overgrown plants provide. When looking at the spacing of your plants also allow some extra space for the new growth that will be rapidly developing in the new growing season. Remember your well grown plants will be much larger at the end of the rainy season when the fungus are savagely on the prowl. Plants and trees in your yard also will have grown in the past year and will be growing more in the rains of summer. June is a good time to think of pruning vegetation that is blocking light and air from our orchids. Come the true heart of hurricane season in September you will be glad that you did! Tree pruning alas, slips to a low priority in the face of an approaching storm. Your orchids will be glad right away that you pruned, rewarding you with harder, healthier growth sure to produce yet more lavish blooms in season.

            A persistent problem in June is how to apply liquid fertilizer to our plants under these often persistently wet conditions. As all of our orchids are in rapid growth in June they need to be fed, ironically this comes in the face of super abundant moisture. While rain contains minute quantities of nitrogen, heavy persistent rain can in fact strip nutrients from our plants by reversing the normal osmotic process. To a degree this effect of the heavy rains can be positive leaching away any excessive fertilizer salts that have accumulated over the dry season but overall the rain leaves them needier than before. Those of us who have kept our plants well nurtured in May will be ahead of this curve but we all must keep our plants fat and happy at the onset of the heavy growing season. For orchid grown in pots with media, the relatively new, slow release fertilizer widely sold as “Dynamite” (i.e.. Nutri-cote) is of especial value at this time of year. Other brands of slow release fertilizer have not proven to be as reliable (neither consistent nor durable) under the hot humid conditions of South Florida. In general, a good rule in June, is that when some opportunities to water present themselves, think rather of applying liquid fertilizer instead of just water. Remember too, the oft repeated bad advice to water your plants before fertilizing them is particularly erroneous in June when over-watering can quickly have negative consequences. In June, as always, replace a watering with an application of the proper concentration of liquid fertilizer. Another frequently sought strategy is to apply fertilizer in conjunction with fungicidal sprays. In general it is not advised to combine balanced fertilizer (20-20-20, 18-18-18) with sprays because with South Florida’s highly alkaline water. Any phosphorus in the fertilizer tends to bind up most of the trace elements when conjoined to South Florida ground water. Phosphorus ( a very active metal) can also have adverse reactions to the fungicide itself, lessening or abnegating its effectiveness. The solution to this dilemma is to use a fertilizer without phosphorus when a bit of nutrition is desirable. The best source is potassium nitrate 13-0-44 (available at farm supply stores in 50lb. bags) which provides the additional potassium our plants crave. 1 Tbs per gal can be added to the spray solution. Be sure to use “Spray Grade” not “Prilled” which would need to be dissolved in hot water. Thiophanate Methyl, Cleary’s 3336 or its combination Banrot or Duosan should be applied prophylactically in June. Keep a sharp eye on your plants for any signs of black rot (Pythium). Should soft black or brown spots appear, they should be excised immediately using a sterile knife as this disease can spread quickly in wet conditions. Banrot gives good control but Alliette is the best fungicide to control this disease if it persists.

            To minimize the need to apply fungicides, June is an excellent time to review our overall sanitation and cultural conditions in the growing area. It is always important to keep the growing area as clean as possible. In June, cleanliness becomes even more essential because water is the chief vector of most orchid diseases. Dead leaves, roots or other dead orchid tissue frequently harbor diseases that can be loosed upon our orchids by the heavy rains of June. Weeds (dead or alive) can hamper air flow and also harbor disease. This month whatever one can do to enhance air circulation is a plus. Under cover, fans to move air are of great value to Phals and other genera. Hopefully, if we have been doing a good job, our plants will have grown significantly since last year’s rainy season. They all may well need more space. Remember that old time orchid growers would say one needs a cat to be a good grower in South Florida because a cat should be able to walk orchid benches without knocking plants down when they are properly spaced.

            Snails and slugs will have the whole world as their stage in June and can travel considerable distances to eat our tender orchid shoots. Baits containing metaldyhyde are very effective if applied evenly and often. Remember, bait draws the pests; spread it thinly but repeat weekly for thorough control. Snails and slugs always require multiple applications. Overly heavy applications of bait will merely waste in the heavy rain.

            Although mites and to a degree thrips are washed away by the heavy rains of June, the warm conditions of summer speed the growth of scale and mealy bugs. At the first sign of either of these pests spray with Soap at 2 oz. per gal or an appropriate insecticide. Oil is no longer an option in the heat of summer. If the soap doesn’t prove effective enough, try something stronger but apply with care early in the morning or late in the evening as the high temperatures of mid-day in June can acerbate phytotoxic reactions.

            June is a great month for top cutting strap leaf vandas, teretes (papilionanthes) and reed stem epidendrums. Most sympodial orchids are already in growth and unless their media in totally broken down are probably best left undisturbed till their new growths have matured and they have flowered. If you have not gotten your Phalaenopsis out of last year’s sphagnum moss wait no longer! Phal roots in soggy medium in June is a receipt for “Fails”.

            For those of us so in love with Florida that we would never think of insulating ourselves with air-conditioning, the rains of June provide pleasant relief from the harsh Mediterranean sun of late spring. As my son Bartholomew at age two so aptly said “Rain sweet as honey”. Enjoy! Our orchids do.


May in Your Orchid Collection

by Motes Orchids in


May Climate Data

  • Average high: 87.2
  • Average low: 72
  • Average mean: 79.6
  • Average rainfall: 5.52"

Excerpted from Florida Orchid Growing: Month by Month by Martin Motes. All rights reserved.

May is a month of transition in South Florida. Early in the month we can expect the driest weather of the year. Because of the clarity of the air and lack of cloud cover, temperatures rise rapidly in the late morning and can reach the upper eighties or nineties by mid afternoon before cooling substantially in late afternoon. Fortunately, over night radiant cooling rapidly dissipates the previous day’s heat. May mornings are a delight, the wise orchidist rises early to enjoy them and to finish his chores before the heat sets in. Chief of these should be extensive dragging of hoses.

            May’s wide temperature swings and dry air suit our orchids to a tee. New growths on sympodial orchids are developing apace and by continuing the careful watering practices of April (i.e drenching them thoroughly with repeated applications of water to saturate their roots and potting media, then allowing them to dry to nearly ‘hard’ dry) we can launch them into the summer in vigorous, disease-free growth. Remember, this saturation can only be achieved with two or more soakings to the point of runoff spaced a few minutes apart. Merely holding the water on the plant extra long will not suffice. The water needs to slowly soak into the roots and media. Test the weight of a “benchmark” plant to be satisfied that it is sufficiently heavy to be totally soaked. The arid air of early May will quickly dry the foliage but the roots can draw on the deep reservoir of water that you have provided with this careful, complete watering.

            With the increased heat and light of May we do not want to put our orchids on too lean a diet. Fertilize with up to 2 tsp. of 15-5-15 per gal of water every week or so. Alternating with Epsom salts and potassium nitrate at 1 tbs. each per gal. is still a best practice during May. Always substitute fertilizer for a watering and apply like the water in two doses to the point of saturation. Never follow the widely stated but antiquated advice to “water before fertilizing”. It’s a receipt for over watering without any basis in logic or science, Now is also a good time to apply a soluble trace or micro element fertilizer. Follow the dilution rates on the package as mixtures and strengths differ. You can apply this in conjunction with the Epsom salts/potassium nitrate but never with the 15-5-15, 20-20-20 or any other fertilizer containing phosphorus. In South Florida’s highly alkaline water the phosphorus interacts with the other metallic elements, reducing the effectiveness of the trace elements. Potassium nitrate, 13-0-46, is the perfect companion to minor elements because it not only lacks phosphorus which would hinder the absorption of the trace elements but the nitrate nitrogen seems to enhance their uptake.

             May is still prime time for re-potting. With cattleyas, dendrobiums and other sympodials, the virtuous among us have long since finished this labor of love, but the majority of us are faced with the moral dilemma of doing the potting now or waiting until next year with the pseudo bulbs of our plants overhanging their pots and proclaiming to the world our sloth. The one instance in which this dilemma must be resolved absolutely in favor of the plant, is when the media has broken down in the pot. This condition will encourage root rot to become stem rot which will pursue the rhizome even into those over arching bulbs. If in doubt, give the media the “nose test”. A pinch of media taken from below the surface of the pot should smell “sweet”. A sour smell or the odor of a pond bottom indicates media that is broken down and must be replaced as soon as possible.

             The case in which this is almost universally true is with plants potted in sphagnum moss. Sphagnum simply will not last beyond one year (even under cover) in South Florida. As the vast majority of commercially produced Phalaenopsis are now grown in sphagnum, recently acquired plants MUST be re-potted annually. As most Phals. will be finishing their flowers, now is a good time to get them right for the new year’s growth. When repotting, one can, of course, choose a more durable media; rock, red wood chips or various mixtures and avoid this annual ritual. Choosing a more durable media will entail modifying one’s watering schedule to accommodate the faster draining, quicker drying qualities of these harder substances.

            May is a great month for re-setting vandaceous orchids whose baskets have deteriorated or that have grown too tall to be easily managed. keikies (off-shoots) can be most safely removed now. In both cases choose the most durable containers for the plants so they need not be disturbed for years. Teak or other hard wood baskets and clay pots last longest. Above all make amply sure that the plants are firmly fixed in their lodging. Vandaceous orchids, above all others, are intolerant of being loosely set. The very height of these plants act as a lever to keep them rocking unless we anchor them securely until their new roots affix themselves to the new containers. Stake and tie them securely until their abundant roots take over. Unsightly staking can then be removed.

            As we bask, lulled into complacency by the nearly ideal weather of early May, Summer sometimes surprises us. Toward the middle or end of May, the weather in South Florida literally undergoes a sea change. The large continental weather patterns which have dominated our weather through the winter and early Spring give way to the tropics and the prevailing south easterly trade winds return us to the interaction of Gulf Stream and peninsular with its characteristic afternoon thunder showers. Although lacking the clockwork consistency of June, the rains have come and we must be prepared for them.

            The relentless and increasing crescendo of rain will, by summer’s end, tip the balance in favor of the ubiquitous fungi lurking to attack our orchids. The time to scotch their plans is now; an ounce of prevention is worth a pound of cure.

            Leaving the taxonomic niceties to the experts, fungi which attack orchids in Florida fall into two broad classes; the leaf spotting types (Cercospora and Phyllosticata) and the soft rots (Pythium and Phytophthora). Fortunately, for modern orchidists, excellent systemic fungicides exist for both types. While these chemicals are no substitute for good cultural practices, i.e. adequate spacing, brisk air movement; the strongest possible light combined with careful watering, fungicides provide the edge to approach near total control of most fungal diseases even in their ancestral home, South Florida. May is a good time to take stock of the collection and see which plants are overgrown and need more space or perhaps even re-potting. The increase in air circulation is well worth the effort. Trimming shade trees and moving plants to brighter locations are also good strategies for May. May is also a good time to consider a preventative spray program before disease has a chance to get the upper hand in our collections. An ounce of prevention begins now.

            Leaf spotting fungi are symptomatic of poor air circulation and inadequate light but even under good growing conditions are rarely entirely absent from orchids in South Florida. This near inevitability results because the same diseases also afflict so many other tropical plants in our gardens. Under the battering of the heavy and sustained rains of our wet season, the most minor of problems can occasionally blossom quickly into a major epidemic. Thiophanate methyl (Cleary’s 3336, Domain, Fungo) is the proven and recommended systemic fungicide to control leaf spotting. It is even more effective when combined with Mancozeb (Manzate or Dithane M45.) Two pre-packaged combinations are available; (Duosan, and Tops MZ ). Always follow label recommendations for rate of application.

            To be truly effective, Thiophanate methyl should be applied initially early in the growing season (IE now!), then again in two weeks and then every 5-6 weeks thereafter across the rainy season. Faithfully followed, this regimen will control nearly all leaf spotting fungus, including the dreaded ‘Thai crud’: Phyllostictina capitalense. A spreader sticker enhances the effectiveness of the fungicide by holding it on the plant through the hardest rain.

            The soft black rot of sympodial orchids and crown rot in vandas are caused by two different organisms i.e Pythium and Phytophthora although in effect they are indistinguishable. Control of these diseases necessitates different chemicals from those used on the leaf spotting diseases. Etridiazole (Truban) has long been used. For the amateur it is readily available in combination with Thiophanate Methyl (the recommended chemical for leaf spotting) in the formulation Banrot. Applied in the same manner suggested above for Thiophanate methyl to control leaf spotting fungi, this pre-packaged combination should be adequate for most circumstances and control crown rot as well. If problems persist two other systemics give excellent control: Aliette (Fosetyl-aluminum) and Subdue 2E (metalaxyl).

            All chemicals should only be applied at the rates and according to the label instructions. If in doubt about whether to or how to apply a pesticide always call your County Agricultural Agent at 305 248 3311 for advice.