Wednesday, October 31, 2007

Effects of a Fan & Heating

My plants haven't looked all that great lately so I'm going to try and increase the circulation by placing a small wig-wag fan at the base of my tomato plants near the 60w light bulb. I did this at about 8:00am this morning. I'm hoping to post the results tomorrow or at the latest next Sunday. Also I'm wanting to paint the heat pipes black and insulate the back wall on Sunday to see if I can increase the daytime temperature and temperature storage capacity.

Tuesday, October 30, 2007

60w Greenhouse Heater

After doing a little bit of research on my electric bill I determined that it will cost me about $0.02 per day to heat my greenhouse with a $60 bulb running twenty-four hours a day. This seems reasonable. I know that it will not provide very much heat but I'm just looking at extending the season not trying to make it all the way through winter.

Here are the results from each 24hr period.

October 27:
October 28:
October 29:

It appears that the light was able to produce enough heat to keep the temperature from dropping all of the way in the evening but it didn't appear to make that much difference during the day. Also the days have been warmer so it is also harder to tell the difference. The 28th was warmer overall but it wasn't as sunny as you can tell by the lack of difference in temperature during the late afternoon.

I need to get some more tests because there are still to many variables involved. Such as the tiny hole that needs patched, sealing the door, etc.... So until I can get those items taken care of I will continue to record the information and share it.

Sunday, October 28, 2007

Initial Temperature Recordings

This weekend I was able to get a baseline set of temperatures recorded from my greenhouse. The weather yesterday was sunny with very little wind if any. The temperatures that I was able to record are shown in the graph below. All temperatures are in Fahrenheit and recorded ever 5 minutes using a thermochron. The inside and outside temperature were measured just above ground level in the shade.

Time span: Friday Oct 26 @ 6:00pm - Sunday Oct 28 @11:00am

Maximum 52.7

Minimum 35.6


Maximum 71.6

Minimum 36.5


Maximum 18.9

Minimum -0.9

This design will warm up but will not hold the heat through the night. In my previous greenhouse I used some 5-gallon buckets to help hold the heat and lightly insulated the back wall and was able to get a temperature positive difference to hold through the night when I put heated water inside the buckets.

What's next
I'm going to try and put an 100watt incandescent light bulb on a timer to come on at a certain time to see how much it can effect the temperature. Also as soon as possible I will be insulating the back wall and patching the small hole in the plastic in the ceiling (manufacturing defect).

Monday, October 22, 2007

Greenhouse #2 revised

I've done quite a bit of research on better materials to use and decided that I really like Solexx. The only problem is that I haven't figured out a good way to create the roof and have it still be portable. I could screw it to some trusses but then trying to put it back together would be a nightmare. I would like to at least cover the sides with Solexx because they could still be portable.

While roaming Home Depot again the other day I found some construction plastic that was 20' wide. This would work a lot better than the 10' wide stuff I used last spring. It wasn't that expensive so I figured I would give it another try and see if it makes it through the winter. This time I made sure to leave the plastic about 8' long on each end. It turned out really nice because I was able to stretch the plastic all the way from underneath the front wall over the top and way down the back wall. The ends even turned out really nice.

It is a little later than I wanted to cover this but I think I can still get another month out of the tomato plants in their and maybe even a crop of lettuce.