March in Your Orchid Collection

Dr. Martin Motes

Ascda. Ann Reaben Prospero " Most Articulate Lady" HCC/AOS

Ascda. Ann Reaben Prospero " Most Articulate Lady" HCC/AOS

March in your Orchid Collection

March Climate Data
Average high: 80.7
Average low: 64.0
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.

Time Release Fertilizer

March is a great month to apply time release fertilizer to our orchids. The ease of application and the carefree joy of knowing that you are effortlessly feeding your charges is irresistible. Time release fertilizer comes in different formulas and also different durations of release. Finding the best one available can take a little research. Remember that modern science indicates a formula of 15-5-15 as being best for orchids in general. The highly alkaline water of South Florida which in some areas contains traces of phosphorus make the use of fertilizer low in phosphorus even more imperative.

Fertilizer manufacturers have been slow to respond to the new science and most "Orchid Fertilizers" on the market are not the best formula in fact for orchids. Look for a formulation with that low middle number. If a low phosphorus one is not available, a balanced formula(13-13-13) is a good choice with the firm intent to supplement the time release with weekly or bi-weekly applications of liquid potassium nitrate plus Epsom salts(1Tbs each).

Duration of the formula is also extraordinarily important. For cattleyas, dendrobiums and most other sympodial orchids a six month formulation applied in March is ideal. By the time the fertilizer is exhausted in September, most sympodial orchids are ready to prepare for their long winter's rest. Terete and semi-terete vandas, mokaras, reed stem epidendrums, Spathoglottis and other terrestrial landscape type orchids will usually continue growing somewhat longer and for these a nine month formula is preferred. This is particularly true if they are grown, as usual, in media with substantial organic content. When the time release is exhausted in nine months the organic material continues to break down slowly releasing a lower level of nutrients to sustain the plants through the winter. In effect the nine month formula provides year round fertilizer for many landscape orchids.

Finally, all time release fertilizer is not created equal. Different brands perform better or worse under South Florida's high heat and humidity. Some last longer and others not so much. This variability results from the different plastic polymers that are used to coat the fertilizer and allow it to release slowly. Many polymers that work fine under temperate zone humidity and cool air and soil, can break down much too rapidly in tropic heat. The sudden release of an excess of nitrogen under this circumstance can cause severe root damage. This damage has been observed even with the "Brand name" product.

In our experience the best product available is Nutri-coat because it has a superior polymer coating that actually performs as advertised under South Florida conditions. It is marketed for retail purchase as "Dynamite". We have had excellent success with the 9 month 13-13-13 formula for our landscape orchids and we have friends who use it successfully for Phals. Whilst they do market an "Orchid and Bromeliad" 10-10-17, the formulae that comes closest to the ideal for orchids are their "Palm and Citrus" 13-5-11 and "All Purpose Select" 15-5-9. Some of these formulae are available at Home Depot and at Independent Garden shops but one can contact them directly at Florikan: or at the their website: .

One to two teaspoons of time release fertilizer per 6" pot should get the growing season off to a good start.

Tasks for March

  • Watch out for mites
  • Spray for Thrips
  • Repot genera emerging from dormancy: catasetums, calanthes, soft cane dendrobiums
  • Continue general re-potting of cattleyas, oncidiums, hard cane dendrobiums etc.
  • Make top cutting of teretes, semi-teretes and reed stem epidendrums
  • Move Landscape plants gradually to brighter light
  • Apply time release fertilizer

Orchid Events

February 29-March 2nd
Fairchild International Orchid Festival- Fairchild Tropical Gardens(10901 Old Cutler Road, Coral Gables) Orchid growers from around the country and the world. Admission also includes the fabulous Roy Lichtenstein exhibit. A great opportunity to buy that membership that you were meaning to get and have free admission again and again and again! Call (305) 667-1651 for directions and information.

Friday, February 29
11 am - Jill Sidran, " Intro to Orchid Culture" Catharine Mannion. "Insects on Orchids"
1 pm - Mirta Heineman, "Intro to Orchid Culture"
2 pm - Ernie Barham, "Intro to Orchid Culture"

Saturday, March 1
11 am - Betty Eber, "Orchid Culture"
1 pm - Alex Lamazares, "Repotting, Orchid Care"

Sunday, March 2
11am - Martin Motes, PhD, " Intro To Orchid Culture"
1 pm - Robert McMillan PhD, "Orchid Diseases and their Control"
2 pm- Ruben Sauleda, PhD, "Growing Dendrobiums"

Free Orchid Classes
Dr. Martin Motes, author of Florida Orchid Growing: Month by Month and one of South Florida's leading orchid experts with over fifty years of growing experience, will begin teaching the special series of free classes beginning on the week of Saturday March 8th at Motes Orchids 25000 SW 162 Ave, Homestead. These classes, part of an ongoing series, cover most aspects of orchid growing in South Florida.

Class Schedule
Saturday March 8th - Introduction to Orchid Growing
Sunday March 9th - Growing Vandas
Saturday March 15th- Growing Cattleyas
Sunday March 16th - Introduction to Orchid Growing
Saturday March 22nd - Growing Dendrobiums
Saturday March 29th- Potting, Mounting and Basketing

ALL Classes begin at 11:00 AM and last about one hour

Motes Orchids will be open to the Public from 10AM to 5PM on days when classes are held.

Motes Orchids is located at 25000 SW 162 Ave, that's just south of Coconut Palm Drive (248 St) and SW 162 Ave. Motes Orchids is 2 1/2 miles due east of the Redland Fruit and Spice Park in the heart of the Redland tropical agricultural district. Take Turnpike south to US 1 at exit 12, continue south on US 1 to 248St, then right(west) on 248St to 162 Ave then left(south) one block to Motes Orchids. Call 305 247 4398 or email for further information.

February In Your Collection