We began working on the new greenhouse in October 2011 by first deconstructing the two large hoophouses that occupied the site. This was no easy job since we had to remove the electric heaters, receptacles, switches, and water lines in addition to the hundreds of bolts and nuts that held the structures together. Once the site was cleared, we began building the post and beam structure that has slowly taken the shape of the greenhouse over the last few months. Currently, the greenhouse is "dryed in" and most of the electrical wire installed.
In the next few weeks we plan to add insulation to the walls and ceiling, install the interior plywood walls, install the waterproof FRP board over the plywood, then finish wiring all switches and receptacles. Although we probably won't need them, we will also install the two electric heaters with thermostats that we used in one of the old hoophouses. These automatic heaters can be used if we ever have to leave the farm while we're growing bedding plants in the spring. Finally, we'll be installing a 20-inch variable-speed louvered exhaust fan (also on a thermostat) with a matching 20-inch intake louvered vent on the opposite side of the greenhouse. Properly ventilating the greenhouse, even in the winter, is essential to maintaining a healthy environment for both plants and humans. We've already learned our lesson on this. To make a long story short, we kept the greenhouse closed up for a couple of weeks and mold started to grow on all the walls. We quickly realized the problem and propped open all the doors and opened a few windows to allow the humidity to escape and the air to drop below freezing. Lastly, we sprayed and wiped the walls with bleach water and are keeping our fingers crossed that the situation is corrected before we need to install the insulation and interior walls. It looks like everything will be OK.
One good sign that the greenhouse will function as designed is that while the greenhouse was closed up, the temperature inside never dropped below 32 degrees F at night even though the outside temperature was in the upper teens. And this was without insulation and an interior wall! I feel confident that when the greenhouse interior is finished and our heat sinks are in place, we won't have to supply any supplemental heat in the spring when we're growing plants, or in the fall/winter when we're growing cool weather crops in the raised beds. The greenhouse should be completed by early March and ready for operation if everything goes according to plan.
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