A monthly growers advice column by Courtney Hackney. Hackneau@comcast.net
An acquaintance recently asked me what I found so intriguing about orchids that made me continue growing them for over 40 years. As I thought about the question, I realized that there were several answers. Mostly, the unending variety of species and hybrids offer a challenge to even the most accomplished horticulturalist. Most long-term orchid hobbyists began with a relatively easy-to-grow orchid and after we mastered growing that one, wanted more of a challenge. Learning to provide the environment for an exotic species from another part of the world must be a rewarding experience for those of us engaged in this hobby because we continue to do it.
Most remarkable is the fact that each year the challenge is a little different because it is hotter, colder, or new pests show up. This year’s pest du jour for me is the juvenile stage of crickets. These appear as pale versions of the adult. They leave damage that looks like slugs, but they also really like new roots. After several nights of looking, I decided to un-pot a damaged plant or two. There were two or three of the little beasts. Once I knew what to look for, I found them on my new phal leaves and on cattleya roots in the dark of night.
These little beasts are quick, and difficult to catch. Several readers have asked about similar damage on orchids they were growing outside in summer and I suggested that the damage was done by slugs. It is not clear if very dry weather promotes this pest or my conversion to large lava rock for a medium. Lava rock provides large spaces where the juvenile crickets retreat during the daylight and makes killing them by hand difficult. Apparently, my small army of frogs that feed at night has not been able to control these pests and I will soon have to resort to liquid Sevin.
Sevin is an old pesticide widely used in gardens, but not usually for orchids. Most scale, the primary insect pest in orchids, are resistant to Sevin, but it works well on other insect pests. Just follow the directions and drench the pot. This kills most insects hiding in pots and seems to also be disliked by bush snails and slugs as well.
I never experienced many insect pests, except scale, until recently. My suspicion is that pesticides, such as Orthene, previously used to kill scale, also killed these other pests. Now that I control scale with an infrequent application of a hormonal pesticide, crickets and other insects have appeared.
Most standard cattleya pseudobulbs are maturing now, which means its time to cease fertilizing heavily. Smaller cattleyas with lots of sophronitis in their background can grow all year long and bloom several times a year. This type of cattleya, popular among windowsill growers, can be fertilized all year long.
It seems that many orchid growers in the area now use Dynamite (also known as Nutricote) slow-release fertilizer [13-13-13] and had lots of flowers last winter and spring. I first saw this product in seedlings I purchased from Carter & Holmes a few years ago and after trying it I was hooked. It provides an even dose of fertilizer for 6 months. This is ideal for hobbyists since mixing fertilizer is time consuming and typically results in over-fertilizing. Use about a half teaspoon for a 5” pot.
Last year a new formulation appeared alongside the standard 13-13-13 formula. While available for some time in bulk, it is now being sold under the trade name Dynamite at Home Depo. It has also appeared from time to time in Big Lots stores at a reduced price. The chemical formula is higher in Nitrogen [18-6-8] and contains minor nutrients as well. It is labeled “All Purpose”, comes in a green tube, and provides nutrients for nine months. It delivered too much Nitrogen for cattleyas, but was great for phalaenopsis and paphiopetalums, which are faster growers. About ½ teaspoon per 5” pot worked well. Apply the fertilizer when the orchids begin to grow in winter. There is enough residual fertilizer incorporated into the medium to provide the orchid with nutrients for an entire year.
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