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.

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.

March in Your Orchid Collection

March 2, 2019fogblogMotes OrchidsComment

MARCH CLIMATE DATA

Average high: 80.7
Average low: 64
Average mean: 72.4
Average rainfall: 2.56"

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

February 3, 2019fogblogMotes OrchidsComment

FEBRUARY CLIMATE DATA
Average high: 77.7
Average low: 60.7
Average mean: 69.1
Average rainfall: 2.07"

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.

Treating Cold Damaged Orchids

January 22, 2019fogblog, articlesMotes OrchidsComment

Cold damage appears on orchids as whitening of the foliage and stems. The white gradually turns to brown as the effected tissue dies. Often this dead tissue simply dries and the damage is limited to the unsightly patches that are left. Frequently, however, the damaged tissue is infected with bacterial rot which can spread in the plant and cause further damage.

Softening of the edges of the cold damaged areas or oozing of brown fluid indicates bacterial infection. Removal of the leaf or stem is a simple but somewhat drastic solution. If one is loath to lose so much of the plant, the most effective treatment for bacterial infection is treatment with cupric hydroxide (Kocide or Champion) which should if possible be combined in equal parts with mancozeb (Manzate or Dithane M45).

This combination is packaged, pre-mixed as Junction. By adding a small amount of water to the chemicals in a jam, one can make a slurry that can be brushed on the lesions.

Be cautious when making the slurry not to inhale any of the dust and never, never, dust these chemicals without wearing a mask.

An old toothbrush is efficient in applying this and your dentist will be happy to have it out of your mouth. Any left over slurry can be placed on a high shelf (brush and all) and re-hydrated later. This stuff is also the cure for those soft spots that appear on Phal. leaves in summer.

For large collections, with extensive damage, one tablespoon per gallon of cupric hydroxide and mancozeb can be sprayed. Mix the two and wait an hour or more before spraying. Do not apply this mixture to dendrobiums which are hyper-sensitive to copper or to bromeliads (ditto).