A monthly growers advice column by Courtney Hackney. Hackneau@comcast.net
If there was ever a doubt in my mind that most cattleyas need a rest in winter with little water or fertilizer, this year put those concerns to rest. Last winter my orchid collection was in North Carolina while I was in Florida. My orchids were left in the hands of “a master cactus grower”. The drought in North Carolina further necessitated keeping my orchids drier than usual because rainwater was my only water source. As a result, this spring and summer has produced the highest flower count and largest flowers on my cattleyas ever.
Vandas in my collection, however, were not as appreciative of the dry conditions and by the time they arrived in Florida in late spring showed stress with slightly shrive
led leaves, no new root growth and less overall growth. With the additional water and heat of a Florida summer, vandaceous orchids in my collection have exploded with new root growth and leaves previously shriveled have taken up water and returned to their normal, plump look. Flower spikes are everywhere on the vandas.
Phalaenopsis suffered the most from being kept dry, largely because they had been moved to a lava rock medium and had not had time to produce the extensive roots that occur in this medium over a few years. Those phals that had been in lava rock for a couple of years grew and flowered well this spring, despite the lack of fertilizer in previous months. With a good supply of water and heat phals, too have put out lots of new roots and leaves.
Most of the bulbophyllums were repotted last fall into Chilean sphagnum, which holds water well and this group was given more water during winter. Only Bulb echinolabium suffered, while all other species in this group grew normally even with no winter fertilization.
Paphs, all potted in lava rock, were a real surprise. Application of peletized lime is necessary in lava rock as well as in other media. The lime washes through the medium faster in lava rock than in a bark medium and application of additional lime was spotty with some plants getting enough and others missing out entirely. Paphs with lots of lime had extensive roots in pots, despite limited water last winter, while those that clearly had not been limed regularly had very poor root systems. Requirements of paphs for the calcium and magnesium found in dolomite limestone were known in England 50 years ago, but largely ignored today where many growers prefer to repot frequently.
Observation is the key to becoming a good grower. Books and articles provide good information that will aid in interpreting your observations, but using that information requires examining your plants carefully from time to time. Even the most skilled grower consults fellow hobbyists and commercial growers, so do not be embarrassed to ask basic questions. Remember though, commercial growers are not concerned about individual orchid plants and may not even grow their own plants. Be careful about interpreting what you see at a commercial operation unless you know that they grow their own orchids, a rarity today. The orchids in many commercial nurseries may have been in Hawaii, Florida, or Taiwan just a few weeks before so observing their medium, watering and fertilizing schedule may not be useful for your area.
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