My solar greenhouse will grow lettuce and cole crops!

[Bobberman]

I add no heat to my greenhouses that have only water for heat storage! As long as I have double plastic the temperature will usually stay above 30 and lettuce and cole crops will grow all through the winter. I even have some of the summer flowers that seem to survive till spring it works for me!.Its fun and I start my seeds in feb using a heat chamber inside the greenhouse with a small 200 watt heater on a timer that only comes on at night ever other half hour.As long as the outside temp stays above 10 and does not go below 10 for a lot of days my green house works! Even on cloudy days with the outside temp at below 10 the inside temp is above 40 which keeps the water above 45 all winter. Water stores heat better than any other material per gallon or weight. Lettuce grows slow but nice! Parsley grows all winter along with radish and peas! Hope to get some pictures soon!

[digitS']

Interesting, Bobberman! You must have gotten it all past the "glitch stage."

I am trying some things in my greenhouse this winter. I really set it up nearly 20 years ago to grow plants in flats. The 200sqft greenhouse has a natural gas garage heater.

The cost of running that garage heater thru the winter discouraged me and I have never turned it on before March. It works fine from there on until I get all the plant starts out of it for the growing season outdoors. A few summers, I have had some extra plants and decided that putting them in the ground in there was safest. Basil and some tomato plants did okay - they could take the heat but keeping them watered was a bother.

This fall -- I decided to move some late-sown bok choy out of the garden into the soil in the greenhouse. I pulled my main bench out and they have room. Along with the transplants, I sowed some seed for bok choy and some other Asian greens. These things are about as good in the cold as radishes.

Well, before the outdoor temperatures dropped into the teens, I had a nice harvest of the bok choy transplants! Didn't take them all but, nearly. I was just noticing today that the ones left have been growing! I should be able to get all of them before it gets real cold. We are on kind of a slow slide this fall. It has been below zero by this time but - not this year.

The seed sprouted in October and the seedlings are growing but very slowly. When the forecast for outdoor temps to be about 15°f or colder, I cover all the plants with another layer of plastic film. I've got pvc hoops set up in there for that. This is kind of the way I've been keeping my potted rosemary alive the last few winters. I just decided to provide a little more room and plant some Asian greens in there!

You have written on the forum about your winter greenhouse before. This winter - I'm joining you!

Steve

[Bobberman]

This past week I dug a weeded area out of the garden to level it and strained 15 - 5 gallon buckets of top soil mixed with some pine shreddings and sand. I will use it in a couple months to mix with compost manure to grow my seeds!The dirt will also hold some heat from the day high temp! I have over 800 gallons of water storage and it works! I even have a gutter collecting water that runs into a 50 gallon drum all winter to water plants! I have three solar greenhouses and two are connected and hold about 600 gallons of water One things most people do not know about water is that when it starts to freeze it gives off 100 times as much heat as it does when it drops one degree. This is what stops my plants from freezing even when there is ice on top of the water!

[digitS']

I don't have that Bobberman.

I also don't have very much room here at home. That's why I am a commuting gardener -- next, you have to figure out a way for me to save on gasoline! But, the lack of space meant that I'm already violating building codes by having so much of my lot covered with buildings - just a few square feet too much.

Anyway, I was concerned about low light and few daylight hours during the winter as well as heat loss. Therefore, I built what is essentially a "sunshed." The northwall and roof were framed & insulated. The interior wall is aluminum wrapped insulation board. What could have absorbed sunlight for heat storage is reflecting light back into the growing space. A sunny day of 32° requires ventilation. I know, I know! I'm wasting energy.

Steve

[Bobberman]

No matter if glass or plastic a double or triple layer makes the difference in retaining heat. Plants do not freeze in my greenhouse even when the water gets some ice in it! No heat just water storage!