ClearSpan Hobby Greenhouse

[Jack Schmidling]

We just purchased a Clear Span Hobby Greenhouse and wonder if anyone else has had any experience with these.

We are still putting it together after 3 days of fighting crappy hardware, lousy instructions and generally poor design.

We don't scare easily but I sure pity anyone with any less fortitude and tool knowhow.

It will be a nice greenhouse when we are done but I would be hard pressed to recommend it to anyone.

We purchased a $25 one from Farm & Fleet just to test the practicality of a small green house and fell in love with the idea. We already have tomatoes ripening and all the plants we put in were 2-5 times the size of our usual indoor starts.

We went back and bought a second one for "spare parts" because it was so cheap but now decided to get a real green house.

The new one uses double walled polycarbonate which should insulate a lot better and wonder if anyone has any idea of the possibility of keeping this warm enough in winter with a one KW heater.

js

[Kay Lancaster]

Jack, I don't know this company, but if you're really stuck, you might try popping in at HGA-L, the home greenhouse association email list -- there may be someone else that has experience with this design.

1KW root zone heating may be enough, depending on your climate and the crops you're growing, and what you're expecting. Consider also thermal mass to help carry you through the night hours.

There's a USDA program that allows you to "build" a virtual greenhouse and test it for your parameters. I'm not sure if it can handle calculations for a small house or not... won't run on the o/s I use.

possibility, again depending on your location and climate, but a distinct possibility given your inquisitive nature and mechanical aptitude, would be to add a solar water heater type design, possibly using a PV pump. The new vacuum solar collectors are very efficient, but I think even Ye Olde

1970's homemade designs might be efficient enough.

One hint for small greenhouses in winter, if you can: Water with room temp water rather than freshly pumped. A simple way is to fill a bucket or carboy near the GH roof, and then let that warm in the house, and water with the warmed water by gravity.

Kay

[Jack Schmidling]

Thanks for the tips and the heads up on SUBSCRIBE HGA-L .... I just did.

I am curious about this one. Is it a happy plant issure or are you saying one can save energy this way?

The latter seems unlikely.

js

[Billy Rose]

If you don't want to chill the ground with water from the tap (you know the pipes are in the ground and the water will be the same temperature) place a 5 gallon carboy (demijohn, whatever) high in the green house where the warmest air will collect and warm the water you are going to use on your plants. This will keep the ground temperatures up. Capice?

[Kay Lancaster]

A little more information on root zone heating vs. air heating in a gh

(paste back together) and was a nice article laying out a lot of the pros and cons of root zone vs air heating in gh work in an edition of the Ball Red Book about 10-15 years ago. I don't happen to have a copy, so I'm unable to get you a better citation... sorry.

Another tactic you might consider for winter heating is to bring back the old hotframe, long a northern midwestern tradition when horses and cows were plentiful. A hotframe is built much like a coldframe, but with a much deeper pit. The pit is bottom-filled with a lot of fresh manure, covered with a foot or so of soil, and then cool season crops like lettuce, carrots, etc. are planted for fresh veggies in the winter.

Yet another approach was laid out in a book I read long ago called "Winter flowers in a sun-heated pit". I was never in a position when I lived in Iowa to build myself a pit greenhouse, but it seems quite logical, and you've probably got appropriate soils in N. Illinois. You'll probably have to interlibrary loan the book.

Winter flowers in greenhouse and sun-heated pit by Kathryn S Taylor; Edith W Gregg Language: English Type: Book Publisher: New York, Scribner 1969]

or

Winter flowers in the sun-heated pit, including the lean-to greenhouse as a complement to the pit, by Kathryn S Taylor; Edith W Gregg Language: English Type: Book Publisher: New York, C. Scribner's Sons, 1941.

Kay

[Kay Lancaster]

You can probably save a smidge that way (if you're dousing the roots with cold water, it takes a root zone heater a bit more to heat the soil again), but mostly it's a happy plant thing, especially with seedlings.

Kay