Zone 8: Growing pains and how to avoid them

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Pre growing conditions

There are two methods for providing the growing opportunity necessary for these palms to reach the ideal planting size quickly. The conventional greenhouse and the more contemporary HID light or the HID light used in combination with a CO2 generator used by many indoor hydroponic growers. The greenhouse is excellent, except that there are problems inherent with their use in Europe. First, they require nighttime winter heat, a tremendous expense for a palm enthusiast, simply attempting to promote and enjoy a hobby. Greenhouses, by their construction of glass or clear plastic (usually single layer) lose heat quickly, and the cost of nighttime heat soon becomes excessively expensive.

The next problem is that there tend to be many overcast autumn, winter and spring days. Cloud cover results in interrupting the arrival of the essential infra red solar rays into the greenhouse, and without this radiation, inadequate heat is provided to produce the desired growth. This is inherently problematic since without exception the secret to rapid palm growth is consistent heat. If the greenhouse provides inconsistent heat, then the plants will experience inconsistent growth. This is unacceptable because it is while the palms are young that they grow most slowly and in greatest need of consistent heat, and much of the skill in growing palms outdoors lies in the ability to consistently provide a favorable growing atmosphere for the palms while they are young. Even if conditions are perfect, the palms will not grow quickly enough for the satisfaction of most palm enthusiasts, so the provision of the best possible growing conditions is essential for success.

When planning to build a greenhouse, be certain that its long side faces south, that you do not have trees and other objects casting shadows on it, and that either it has a low ceiling height, or that you have high shelves in it on which to place the palms. If you have these things then you are on the right track and you should next consider the proven benefit of reflection. If you have too many overcast days to facilitate good growing, then reflective devices will not help, but if you have consistent sunny days, but experience difficulty obtaining appropriate heat levels due to an extreme northern location, then reflection could be the answer. Plywood painted flat white or tin foil backed polystyrene insulation sheets both provide inexpensive reflection, reradiating the suns rays to approximately 70 % of the sun s initial radiation. The reflection must occur outside the greenhouse, and redirect the suns rays into it. A good method is to attach the plywood at the top rear portion of the greenhouse in line with the top of the rear wall. The higher the reflective device extends above the roof the better, but don t forget the force of the wind that can tear off your devices and hurdle them dangerously through the air. Devices on the west and east sides are also helpful, and correct placement can slightly more than double the effect of the sun, so if you consistently have 80 degree days in the winter, you can expect them to increase to 90 degree days with reflection. And don t forget that your ultimate test date is December 21st, because that s when the sun s rays are most distant and your daylight is shortest, and not several weeks later when your temperatures are at their lowest.

In most cases a double growing system is probably best. That is, to grow the palms in a greenhouse during the sunny months when temperatures are warm, and then move them into a protected area such as a basement or garage when the nighttime temperatures drop consistently into the 30sF (0-5deg.C). This eliminates the expensive and impractical necessity of providing winter heat in the greenhouse, but it unfortunately does forego the ability to produce rapid year-round growth which is so essential to the psyche of the typically impatient palm enthusiast.

Perhaps the most practical method of growing palms in Europe would be with an HID light or with an HID light in combination with a CO2 generator. With this system, HID (high intensity discharge) lights produce the light necessary for photosynthesis, replacing the need for natural sunlight. This in turn eliminates the necessity of clear sheeting to enable the entry of natural sunlight. Since clear sheeting allowing sunlight to enter is no longer necessary, materials with great insulating properties can be installed to contain heat within the growing area. For instance, a garage can be double or triple insulated, to the extent that it maintains any heat generated for several hours. And with the appropriate level of insulation, a single HID light alone will suffice to provide adequate heat for growing as well as the essential light. For conventional indoor gardening purposes, a 1000 watt light will serve a 10 by 10 foot area. However, palms require less light than conventional gardens, and a 1000 watt light will probably serve a 20 by 20 foot area. Particularly if the walls are painted flat white to reflect light back onto the back of the palms. There are also smaller, less expensive HID lights that work just as well, but for smaller areas.

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