We have recently finished moving things around in the greenhouse. Jeb a friend and cohort in research in PNW gardening, is working on his degree in permaculture and horticulture with a focus on our climate and region. He will be conducting several studies using my greenhouse and the one we completed for him this Summer. Those studies will be in passive and low energy input (his greenhouse) and a heated greenhouse using supplemental lighting (my greenhouse.) These studies will include variety trials to determine those best suited for our climate in both systems. Also results of different methods of growing: media bed, wicking bed, and soil beds. This will give us a spectrum of plants and growing methods suited to the plant and the environment.
Jeb's greenhouse is the white one in my photos. His will be only passively heated by the sun, heating the deep soil beds as a thermal mass. My greenhouse as many of you have seen, is heated with a pellet stove. Water temps stay about 70 and air temps vary. He will use no supplemental lighting, I will have lighting for those plants that need the day length to flower and fruit. Our goal is to provide a spectrum of varieties, growing conditions, and growing methods that would suit any gardener in the PNW that wants to grow something year round.
The media beds are 12" deep overall. They have a 4" lava rock base and about 8" of pea gravel for the primary media. This is to give a good place for the bacteria to colonize, we will get a small amount of trace minerals from the lava rock, the pea gravel is a cost effective, affordable, and readily available in abundance in our area. The media beds are a flood and drain using bell siphons.
The wicking application is using the media beds, but adding a nutrient rich compost based soil in pots that the plants reside. The beds are only flooded to the point the pots receive the nutrient rich water. We did this last Spring and this Summer with terrific results, but no comparison with a soil only and media only control group. The plants rooted through the pots into the media beds. There were tomatoes, peppers, a potatoe, and several other varieties that did superbly.
One of the major issues for our region is the fact that we get the least BTUs of sunlight in the entire continental US other than possibly Alaska. So varieties that have adapted to this condition and those that are suited will be determined and tested in both systems to see how they produce. Supplemental lighting will be kept to a minimum just to extend the hours of daylight to set fruit on those varieties that need it. For those that want to keep energy costs down, always have the option of seasonal planting.
We will have other examples of Northwest systems we have built running in the next few weeks. Two of which are in Portland, photos of their greenhouses are posted in my pictures as well. They are members here and I am sure will be reporting in their results as time goes on. Both are media based systems, although they will be experimenting with some vertical growing, rafts, and other variants.
We are working on a system that will be a series of insulated coldframes and a heated space for the fish tanks. The goal here is to reduce the footprint and the necessity for permitting a greenhouse. It should also be more economical to build and heat than a greenhouse. I will update as we go.