solar powered heater for cold frame

I don't want to run an electrical cord to our cold frame and was thinking about putting in a solar powered heater. One that would kick in at night. Anyone ever hear of a thing? Just curious.

Now that would be great! I wonder if the solar powered lights would put out any heat. I wonder if the light from them would disrupt the growing of the plants. Something to have a discussion about!

I have used thermal mass in my hoops before. I used milk or water bottles filled with water and painted black. these work pretty well for extending the season several weeks on either end of a growing season.
see this thread from another forum.
http://forums2.gardenweb.com/forums/load/strucs/msg0418124021239.html

some more ideas.
http://thesoiltoil.com/2012/03/16/diy-thermal-mass-for-the-cold-frame/

http://www.urbanhabitatchicago.org/projects/2613-garden/

How did you find those sites that fast Camp and post them, lol! I will have to read them!

Thanks- I had considered that, but don't have a big area to deal with (3 foot by 5 1/2 foot). Thanks for the info. How many jugs would you need? Are bricks painted black as effective or not?
I'm guessing that I won't find a solar heater.

After reading your links and checking some other forums. I think adding some Thermal Mass probably is the best answer. Thanks!

Triciasgarden wrote:Now that would be great! I wonder if the solar powered lights would put out any heat. I wonder if the light from them would disrupt the growing of the plants. Something to have a discussion about!

I haven't thought about those solar powered lights that come on at night. They serve a two-fold purpose, lighting during winter and possibly some heat. Good thought.

From what I have read, the solar powered lights don't really put off any heat because they use led lights, so my suggestion wasn't good. What I was thinking from doing some reading is water your plants before it gets dark as moist soil keeps warm longer. Maybe use smaller soda bottles and spread them out since your cold frame is smaller (just my thinking). Use food coloring in the water to make the water black as that will help them retain more heat. Then before it gets dark, cover the cold frame with a blanket to help retain heat. You would have to remove the blanket before the sun starts to heat it up or it would probably get too hot and kill the plants. It would be interesting to see what the temperature is at night.

I have several solar lights in my flower beds and even beside the strawberry bed but they don't give off any heat so that won't work.

I like the idea of the bottles or jugs painted black to retain some heat. I'll have to try that besides 2 layers of plastic. I'm rethinking next fall's crop extension.

great question on a solar small green house heater we have been looking for one as well.....

we tried the holiday lights and water jugs....but the jugs/bottles were clear....we will paint and try it again....and does anyone know if you are to keep the caps on or off?

we too are trying to re-think our fall/winter gardening
hugs
rose

Triciasgarden wrote:Then before it gets dark, cover the cold frame with a blanket to help retain heat. You would have to remove the blanket before the sun starts to heat it up or it would probably get too hot and kill the plants.

Leaving a blanket on when the sun is out would only shade your plants. The principal input that causes a greenhouse or coldframe to warm up is sunlight, so having a blanket blocking it would allow for the temps to be near ambient temp outside ....depending on the lag caused by whatever the insulation properties of your greenhouse would be.

interesting thread! i've been intrigued by methods to extend growing season here - and so far, my solution has been to put a cold frame 3x3 up against the side of my house with clear plastic sheeting over and filled lidded milk jugs around perimeter to keep the plastic from flying off. and this cold frame is right next to my dryer vent output. so the warm air flows near the box - not directly over, just near. it seems to have a warming effect on the closer squares. we don't use fabric softeners or anything like that so i feel this is safe option. (we've been doing it for 3 years now). i used to use a 'old style' lightbulb for heat and light, but those are getting harder to find and i worried about the electric cord. . . .

I was looking at converting wind energy in to heat for mine. I've tested a few things but nothing great yet. I have a few more projects planned to test out, will report if anything seems to work.

I don't mean wind -> electricity -> heater. I'm talking wind -> friction or wind -> electrical resistance (friction) -> heat.

CharlesB.....I'll leave the hard stuff to you guys....or gals, in the know. Keep us posted on results.

I am curious about the original poster's intent.... did you want to grow things all winter or do you simply want to extend your growing season?

cyclonegardener wrote:I don't want to run an electrical cord to our cold frame and was thinking about putting in a solar powered heater. One that would kick in at night. Anyone ever hear of a thing? Just curious.

If you're wanting to use solar power to power anything at night, then you'll need some sort of battery. If you're charging the battery w/ solar panels, you'll need some sort of conditioner/regulator to make sure that the voltage from the solar panels to the battery doesn't damage your battery.

Also, for anything of significant wattage to produce heat enough to bother with in a cold frame/greenhouse, you're going to need significant batteries to store that power overnight.

If your quest for solar powered heat is a rooted in thriftiness, it will take a while before you see a return.

I have two different systems going right now. I have a 5 x 10 garden that we built before learning SFG. My husband built a pvc canopy and we have heavy gauge plastic clipped to it. It goes up to about 8 feet in the back and down to about 4 ft in the front. We're using a halogen shop light in there and still have huge tomato plants that have survived from April's planting. We think it's a 150 Watt light but it might be a 250W.

I had a few plants that were touching the outside walls and the cold got to them. I lost a green pepper last night, but it was about done anyway. I have one eggplant still growing babies so I've let it stay, but it's pretty ragged.

We also have 3, 4x4 table tops with light weight green house covers and 175 W Christmas light strings. They work for a light frost, but last night we got a hard freeze and I lost the spaghetti squash I had tried to save in there. I think that the difference is the raised beds let the cold penetrate too much and that one large lamp seems to generate more heat than the small bulbs.

We have new plantings in the minis that are cold friendly and are going to give up on the items that aren't.

HERE'S WHERE YOU CAN FIND PICTURES OF WHAT I'M DESCRIBING: https://squarefoot.forumotion.com/t14182-hi-i-m-new-to-the-forums-and-in-your-area#144771

I love your set up Audrey!

Fox, at the Seed Exchange, just read the different posts. They are all individual and will list what they have available. If you see something you like, look for the little icon beneath the person's avatar area with P.M. in the box and click on it to send them a P.M. (personal message). When they answer you later, you'll have a flashing P.M. at the top of any thread you happen to open. Just click on it and it'll got to the messages.
Good luck.

cyclonegardener wrote:I don't want to run an electrical cord to our cold frame and was thinking about putting in a solar powered heater. One that would kick in at night. Anyone ever hear of a thing? Just curious.

I've just read Mel's ANSFG answers book and in it there is mention of using water filled bottles in a cold frame as a heat sink that heat up in the day and radiate some warmth at night .

Re the Photo Voltaic panel idea .
You could run a 5 watt 12 volt pair of bulbs wired in parallel off two 12 volt batteries wired in parallel . They should run for about 75 % of the total amphere capacity of the batteries which should cover a 12 hr period of light / heat with ease .
The 10 watts of heat in a still air small cold frame could give you around 50 oF . Connected to a poho electric switch they can be made to only come on at dusk and automatically turn off when it becomes light .

plantoid wrote:

cyclonegardener wrote:I don't want to run an electrical cord to our cold frame and was thinking about putting in a solar powered heater. One that would kick in at night. Anyone ever hear of a thing? Just curious.

I've just read Mel's ANSFG answers book and in it there is mention of using water filled bottles in a cold frame as a heat sink that heat up in the day and radiate some warmth at night .

Re the Photo Voltaic panel idea .
You could run a 5 watt 12 volt pair of bulbs wired in parallel off two 12 volt batteries wired in parallel . They should run for about 75 % of the total amphere capacity of the batteries which should cover a 12 hr period of light / heat with ease .
The 10 watts of heat in a still air small cold frame could give you around 50 oF . Connected to a poho electric switch they can be made to only come on at dusk and automatically turn off when it becomes light .

That sounds very interesting. Thank you.

plantoid wrote:

Re the Photo Voltaic panel idea .
You could run a 5 watt 12 volt pair of bulbs wired in parallel off two 12 volt batteries wired in parallel . They should run for about 75 % of the total amphere capacity of the batteries which should cover a 12 hr period of light / heat with ease .
The 10 watts of heat in a still air small cold frame could give you around 50 oF . Connected to a poho electric switch they can be made to only come on at dusk and automatically turn off when it becomes light .

Sent this to hubby to interpret! Me and electrical are incompatible. But would be nice if a little heat could be had without much cost or ongoing cost. I am trying this to see how cheap I can get

plantoid wrote:

cyclonegardener wrote:I don't want to run an electrical cord to our cold frame and was thinking about putting in a solar powered heater. One that would kick in at night. Anyone ever hear of a thing? Just curious.

I've just read Mel's ANSFG answers book and in it there is mention of using water filled bottles in a cold frame as a heat sink that heat up in the day and radiate some warmth at night .

Stones will also work for a thermal mass(google Sepp Holzer. He uses large rocks to grow citrus in the Swiss Alps). If you build the base of the cold frame using bricks, then your cold frame can provide its own thermal mass. Cinder blocks don't seem to work well, though solid concrete probably will(haven't tried it). I've reused gallon milk jugs filled with water for thermal mass before, and it worked well enough.

CindiLou wrote:

plantoid wrote:

Re the Photo Voltaic panel idea .
You could run a 5 watt 12 volt pair of bulbs wired in parallel off two 12 volt batteries wired in parallel . They should run for about 75 % of the total amphere capacity of the batteries which should cover a 12 hr period of light / heat with ease .
The 10 watts of heat in a still air small cold frame could give you around 50 oF . Connected to a poho electric switch they can be made to only come on at dusk and automatically turn off when it becomes light .

Sent this to hubby to interpret! Me and electrical are incompatible. But would be nice if a little heat could be had without much cost or ongoing cost. I am trying this to see how cheap I can get

RV solar electrical kits would be an idea, I would think. Not sure how much you could heat and for how long, but once you pay for the system it would pay you back nicely if you could get it to work.

My "mad scientist creative mode thinking" just had a picture of a table top box over the top of a compost pile providing the heat! Maybe a slide out composting box?! Now THAT would be efficient, LOL!

AJR ,
The gasses and moisture released from the decomposing materal off a compost heap would like as not cause you big probs for to get any heat benefit to the above surface plant life life as the whole thing would have to be fully enclosed .

Now a hot bed of say a pit of 3 foot deep part rotted manures with a decent layer of MM on top & a 2 foot high cold frame is a different matter as you'd be growing down into the material ..it's a well know way of having a " HOTBED "