Kevin Wang wrote:House exterior walls are not waterproof. If you have super high humidity air on the outside, it will make its way into your house's walls and feed mold, rot wood, etc. cement is not waterproof. stucco is not waterproof. wood is not waterproof. tar paper may be pretty waterproof, but usually when the side of a house is layered with tar paper, kraft paper, or house wrap, it's layered, much like shingles. it's designed so that gravity will pull water droplets (i.e. from rain) away and out from the building. If you build a greenhouse, humidity is air, not water droplets, and will happily go upwards into your house.
I would not recommend an attached greenhouse, because of the humidity.
An attached/enclosed porch is different, because there is no moisture.
David Maxwell wrote:... The pumps to pump the water through the radiators (my "heat exchangers") are controlled by a differential thermostat, so that they run only when the temperature of the air, (in the peak), is higher than the temperature of the water. It was apparent that the heat was coming out of the water in the tanks reasonably efficiently, as the temp in the tanks drops as much as 20 degrees C overnight. But I have gilded this lily a little - I am pumping the water through black plastic piles buried 8" down in the growing beds, 24 hours a day, (at least when the cheap pumps are still working). I did this on the principle that heating the plants' toes made more sense that trying to heat the entire volume of air in the greenhouse. But it had an unexpected effect - it added the soil in the growing beds to the thermal mass. The temperature in the tank with a functioning soil pump runs about 2 degrees lower than the other one, and the soil temperature in the the "circulated" beds, runs 2 degrees higher than the ones without circulating water. In addition to the pumps, I have 4 large computer fans which draw the air from the peak through the radiators. All these pumps, fans and controllers run off a 90 Watt P-V panel with a small battery storage (actually the battery from my ride-on mower) which carries the soil pumps through the night. Obviously, since I am able to quote these temperatures, I also have a monitoring system capable of storing a log of data drawn from, (in my case), 4 separate channels.. (Mine currently polls the temp sensors every 10 minutes).
David Maxwell wrote: Does movable thermal curtain insulation count as "active"? (That is my next "refinement", after I get, and install, some new pumps, which hopefully will last a little longer.)
bob day wrote:Great Links Tom, very informative. I've been puzzling over how to grow figs and actually get a good crop, looks like the fruit walls are the solution. I had no idea they were so effective, or had such a long history
Gilbert Fritz wrote:One interesting way to grow organic matter for a plot is with azolla ferns in a pond. Azolla fixes nitrogen from the air, so you would be importing nitrogen and carbon. The pond will only benefit from removed nutrients, not suffer. And the azolla mat makes a good weed smothering mulch. Azolla is one of the fastest growing plants on earth under ideal conditions.
Gilbert Fritz wrote:I'm glad you liked my website! As always, when soil balancing comes up, I'd recommend Steve Solomon's book, The Intelligent Gardener. I disagree with him on some things, and his tone can sometimes be off putting, but it is the best book I've found yet for small scale growers looking to balance their soil.