Hi bogy, I don't think there are to many people on this forum familiar with AK conditions.

John

This seems to be working for me. I had tomato sprouts out last night, greenhouse low -0.3C and they look fine.

RE: New greenhouse - what can I do right now with it?

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* Posted by ljpother 3a (My Page) on
Sat, Mar 28, 09 at 19:24

I just put some water in my greenhouse. I realized my rain barrel wouldn't mind being used to hold water :) and I had other containers. I placed a layer of 4l ice cream pails under my flats, which should moderate temperature fluctuations. Altogether, I put about 450 litres of water in. US gallons ~120, imperial ~100. It sounds better in litres. Hopefully, this will be enough to keep the night time temperatures above freezing.

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RE: New greenhouse - what can I do right now with it?

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* Posted by ljpother 3a (My Page) on
Tue, Mar 31, 09 at 11:16

The water seems to be having an effect. Lows have been -1,-0.3C,2.3C. Outside temps were -8,-8,-3C. It seems the water is gradually getting warmer and that when the temp tries to go below freezing the heat capacity of the water holds the temperature steady. On the cold nights the green house temp went below freezing about 7AM and stayed there until the sun gets around to the greenhouse, 3-4 hours.

Planted 4 tomatoes in GH with snow still on the ground. Even plant have to be tougher in Alaska.
Tried 5 ways to post pictures, no go .
So much for the easy way. What's the hard way?
http://i274.photobucket.com/albums/jj269/bogydave/GH4-2-09.jpg
[IMG]http://i274.photobucket.com/albums/jj269/bogydave/GH4-2-09.jpg[/IMG]
http://s274.photobucket.com/albums/jj269/bogydave/?action=view&current=GH4-2-09.jpg

Why not just add a small inexpensive electric heater? You can also insulate it with clear bubble wrap inside. You can get it cheap from any packaging house.

Plants looking good so far. Covering the boxes is working well. Cucumber seeds sprouted. Soil temp holding at 70 deg F. :)

ghr2
Cost prohibitive when getting down in the teens at night still, wire size to gh would have to be larger to supply enough current to run enough heater to keep it above freezing at night.
Take allot of bubble plastic for a 8 X 12 gh to get the "R" value so it would be efficient enough.
I am able to cover the heated soil boxes & keep the plants above 50 deg at night now & when plants get larger if it's still getting cold at night i'll cover them with 5 gallon buckets (jbest's idea). by the time they out grow the buckets, it'll be warm enough during the short nights that not supplemental heat will be needed.
Thanks for the bubble plastic idea, I never though of that one. I can use it for other applications like a dome cover over the heated soil boxes.

Wall-o-waters are 18 tubes 18 inches high of water encircling a plant and can be positioned as a teepee to completely cover the plant in solar-heated water. Your ground heat would also contribute. I have this set-up in a small bed with heat wire underneath and the cucumbers are above the water tubes now. I have wood heat and I check the stove every 3-4 hours in the night and keep it 50-65. It is a 20 foot square wooden pyramid with poly battened on both sides and dirt banked up on the plastic around the bottom. I just built it in February on the frozen ground. Each wall-o-water holds about 3 gallons so if you had say 33 x 3 gallons, you would have a 100 gallon solar heat store. By the time your plants reach the top, it should be less cold at night.

When you plant will likely depend on many things. For what it is worth, we were harvesting tomatoes into December (in Zone 9 - foothills at 2400 feet elevation). In February, I dismantled the raised beds as I was moving them to an area nearer the greenhouse. At that time I took several volunteer plants (Sweet 100) which has sprouted - about 10 or so - and potted them in the greenhouse. I now have a few cherry tomatoes that are ripe - and have harvested some of those - and have many green ones on the plants. The plants are about 4 feet high in the greenhouse, and I have transplanted many more into the new raised beds - those are shorter as I pulled off lower branches and planted deep. I did not have to heat the gh except for 2-3 nights. I also planted kohrabi from seeds and we have been eating that for 2-3 weeks now. Lettuce and chard is also ready. My heirloom seeds are up - some still in the gh and some already in the raised beds, but they are only about 6" high. I have so many tomatoe plants that I will need to build another raised bed. I eventually want to see if I can get tomatoes year round - don't know if I will be able to do so but as it is we seem to have a fairly long season as we ended harvest in December and are getting more now in April - though only a few.