smurf428

Hi everyone sorry but i have another question. Over the weekend my husband and i built a green house from pvc pipes, i found an idea online, we wrapped it in vapor barrier. I'm very excited, after asking for one for over 3 years finally i have my very own.. Anyways my question is, I have 2 basjoo bananas and in order to keep them growing somewhat over winter, what temp must my greenhouse stay above.. I just moved to alabama in july from canada so gardening down here is all very new to me.. I have a small space heater i could add on low if it needed it.. Just looking for a few tips on temps, or hints to keep it warm
thanks
jen

Velutina

I grew bananas in a greenhouse for years (see my avatar). I tried to keep the minimum temp above 55F. I used about 500 gallons of water as a heat sink, which really helped with heating costs. Another factor is soil temperature if your plants are in the ground. I got around that in zone 6 by having the ground level inside the greenhouse about 2 feet below outside ground level.

What I would do for heating... I had 55 gallon drums filled with water, and a 300 gallon salt water aquarium. I would let the greenhouse get as hot as possible during the day (easily 90-100F during a sunny winter day with outside temps in 40s). The water would heat up to about 85F. During the night, the water temp would go to about 70 before any heaters kicked in. Even with 30F temps outside, the greenhouse could stay above 55F just with the water heat sink. It worked well for me because I used water circulation and fans blowing on the water to control how fast/slow the water temp changed.

something to think about..

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Adam

smurf428

Instead of heating the ground could I acheve the same affect if i lifted the pots off the ground with say some bricks or wood pieces?? Since this is just a cheaply made greenhouse only costing me $120 for a 10'x10' size. I would like to keep everything fairly cheap, thats why i was thinking of a heater or maybe even christmas lights?? I just need it to stay above freezing maybe 50 degreese at night?? I have some cannas and elephant ears in there as well. I know I could let all just go dormant for the winter but this way I would get a head start on spring. My husband and I plan to make a nice greenhouse once we buy a place of our own.

Velutina

The biggest factor you will face is how well insulated the greenhouse is. If the vapor barrier you're using is thin, you will likely need a significant heat source (ie electric heater). If the greenhouse stores heat well, you might be able to get away with using heat sinks or christmas lights.

One winter, I wanted to see if I could get away without using any supplemental heating. I wrapped my greenhouse in the large bubble wrap and then covered it with thick clear plastic (>5mil). Following a sunny day, I could maintain the greenhouse 20-30 degrees over outside temps. If I had just bananas (and not tropical coral/fish), I could have turned my gas heater off completely.

A cheap option you could try is start collecting 1 gallon milk containers, fill them up with water, and line the walls of your greenhouse.

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Adam

Velutina

As far as what is the minimum temp bananas will continue to grow...
I'm sure there will be variation between varieties, but... From my experience and what I have read, 55F seems to be the temperature at which growth stops. That doesn't necessarily mean you need to keep the greenhouse at 55F at night. You may still get growth with lows in the 40s if the daytime temps are warm enough.

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Adam

smurf428

Velutina thanks so much for all your info.. My vapor berrier is pretty much just the common house hold used one, so I'm thinking I'll get my space heater ready. It's about 80 through the day and my greenhouse is 90.. I was opening the door to let some heat out but now I'm thinking I should leave it closed to keep that heat for the night.. It's all new to me so I'll have to keep checking to keep the temps right

Velutina

Good idea. Keep the door shut and put stuff in there that will absorb the heat during the day. I think water works best, but you can use rocks, bricks, etc. Adding some open water containers will absorb heat and raise the humidity. My bananas would do fine when I let the greenhouse get up to 110F as long as the humidity was high. Heat sinks are dirt cheap and will save you a ton on the electric bill, especially when you have a well-insulated greenhouse!

You can buy 55gallon water storage containers. Fill two up with water and put a piece of plywood on top. You have a table for your plants, excellent heat-sink, and 110 gallons of water storage. Win-Win-Win. You might even recoup the cost of the containers in the money you save on your electric bill.

Happy banana growing

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Adam