Growing Tips for September 2000

by Courtney T. Hackney 

EMAIL at Hackneau@bellsouth.net

 

Once again it is time to prepare for cooler weather.  Careful attention to both plants and potential problems will save time in the future.  If you have had problems with scale, mealybugs, or mites now is the time for a little preventative maintenance.  There is just enough time left to treat these pests before greenhouses are closed or until plants are moved inside.  Thorough spraying three times ten days apart will generally keep these beasts at bay.  The purpose of the three treatments is to kill individuals that survived the first and second treatments as eggs and do so before they can lay additional eggs.

Rots are another potential problem, especially when we put plants back into a closed greenhouse setting.  Remove diseased parts of plants and treat the wound with cinnamon powder.  Let the plant dry a little more than you might normally and put it in a place where you will see it.  If you find you have more than just one or two problems, a more extensive spraying treatment may be necessary using one of the approved bactericides/fungicides.  If you have very pure water (rainwater, R/O water, etc.) you will not have to use the full dosage recommended.   I have had good success using this type of product at half strength with rainwater.

Fall is also the time of year when day length and temperature become ideal for stimulating flower production.  As nights get cooler move Cymbidiums into higher light.  Hybrids in this group of Orchids generally like cooler fall weather and most require it to bloom well.  In California, growers do not take Cymbidiums inside until nights get frosty.  Similarly, many members of the Zygopetalum group, including intergeneric hybrids, will initiate new growths and flower spikes only when night temperatures dip into the 50s.  Once new growths appear with spikes, return plants to the greenhouse.  Last fall, I left plants of Zygopetalum Blackii and its hybrids outside until night temperatures were in the low 40s.  All bloomed including one large plant that had never bloomed before and none were harmed. 

Cattleyas also generally enjoy the cool nights and will bloom with more intense color on longer, stems.  Most Cattleyas do not like to go lower than 50 degrees F, but Laelia purpurata will not mind even lower temperatures. 

Winter blooming Phalaenopsis (standards) require at least a 20-degree day/night temperature change and a week or two of nights into the upper 50s or low 60s to begin the blooming process.  Indoor growers may need to place Phals on an outside porch or some other well-shaded area for a couple of weeks to initiate spikes.   Small Phal seedlings should not be stimulated to flower and be kept warmer so that they will get maximum size from the summer's growth.  They will flower later and have more strength to carry flowers.  Phals will continue to grow as long as their roots stay warm.  Cold rain or water will stop both the growth cycle and slow the flowering process so be sure to move spiking Phals back inside or into the greenhouse before day temperatures get too low.

Don't forget to check heaters, get gas now (much more expensive than last year) so that it will not be a rush.  The prediction is for a colder than normal Fall, so don't be caught by an early freeze.