bogydave
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Posts: 197
Joined: Thu Apr 28, 2011 3:11 am
Location: Alaska

Solar heated soil box/bed

I experimented last year trying to heat the soil up to be able to grow tomatoes outside. I came up with this. I got better tomatoes than ever before & even a few ripe ones. (GH plastic sheeting sides, filled with compost) I got 6 to 8 degree f warmer soil on sunny days.
So if you have a plant you want to grow but needs some warmer soil temps try something like this. May help. Will try it again this year & stake the tomatoes up so the soil gets more sun & see if it helps.
[img]https://i274.photobucket.com/albums/jj269/bogydave/SolarRB4toms.jpg[/img]

[img]https://i274.photobucket.com/albums/jj269/bogydave/sloarRB.jpg[/img]
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orgoveg
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Joined: Sat Jun 06, 2009 5:06 pm
Location: Ohio

That's a really creative idea. You folks in Alaska must know an awful lot of tricks that the rest of us in the northern states could benefit from.

Are you growing an early maturing variety of tomato? I'm thinking that you might get the same benefit (or maybe more) by covering the soil with black plastic after the soil warms up. Black absorbs heat from the sun (as opposed to reflecting it) and the plastic keeps the cooling winds off the soil. Watering is the complication involved, but the plastic will also retain moisture. I'm just thinking out loud... err...out fingers ;) Staking the plants will surely help.

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veteran
Full Member
Posts: 34
Joined: Tue Apr 26, 2011 5:24 pm
Location: Zone 9

Re: Solar heated soil box/bed

bogydave wrote:I experimented last year trying to heat the soil up to be able to grow tomatoes outside. I came up with this. I got better tomatoes than ever before & even a few ripe ones. (GH plastic sheeting sides, filled with compost) I got 6 to 8 degree f warmer soil on sunny days.
So if you have a plant you want to grow but needs some warmer soil temps try something like this. May help. Will try it again this year & stake the tomatoes up so the soil gets more sun & see if it helps.


Awesome innovation. Seems a bit pricey for tomatoes though. It would be nice to see something cool in there (Bhuts, etc) 8)

-- Orgoveg, excellent idea with the black bags.

cynthia_h
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Location: El Cerrito, CA

bogydave, we had a very active member from Anchorage in Summer 2009. Here's one of her threads on [url=https://www.helpfulgardener.com/forum/viewtopic.php?p=85917]tomatoes[/url]. Unfortunately, she was never able to post photos, but her writing was quite detailed. (I say "was," because we haven't heard from her since 2009.)

She wrote about many veggies: peas, green beans, tomatoes, and I can't remember what-all else. But a Search of the Forum on her name or other criteria will find her, one of our most prolific Alaskan, posting members.

Cynthia H.
Sunset Zone 17, USDA Zone 9

bogydave
Senior Member
Posts: 197
Joined: Thu Apr 28, 2011 3:11 am
Location: Alaska

orgoveg wrote:That's a really creative idea. You folks in Alaska must know an awful lot of tricks that the rest of us in the northern states could benefit from.

Are you growing an early maturing variety of tomato? I'm thinking that you might get the same benefit (or maybe more) by covering the soil with black plastic after the soil warms up. Black absorbs heat from the sun (as opposed to reflecting it) and the plastic keeps the cooling winds off the soil. Watering is the complication involved, but the plastic will also retain moisture. I'm just thinking out loud... err...out fingers ;) Staking the plants will surely help.
I tried the black plastic but got lower soil temps, I found that clear plastic let the suns rays pass to the dark colored soil & heat the soil. I got about a 9 to 12 degree soil temp gain (4" deep in the soil) on clear plastic over black plastic. That is one of the reasons I made the box with GH sheeting, to let the heat get into the soil & hold it in a little longer into the night.

Pricy tomatoes for sure. But so are the ones i grow in the GH. But the flavor of a vine ripened tomato (for me) is worth it.

I've been trying to get good flavorful ripe tomatoes outdoors here for years. I had my best success lat year with this box & the "4th of July" hybrid. A few ripe tomatoes with some flavor, Not as flavorful as the same tomato in the GH but some tomato flavor.
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Gary350
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Joined: Mon Mar 23, 2009 5:59 pm
Location: TN. 50 years of gardening experience.

Black plastic is glossie the surface reflects some of the sun light.

Clear plastic lets the sun light pass through to the soil. Soil is not glossie so the sun light is scattered in all directions and adsorbed.

If you use very thin sheet metal painted with FLAT black paint it will get hotter than glossie black plastic.

If you want more heat then set up a mirror to reflect more sun light to the area your trying to warm up.

Bobberman
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Joined: Tue Nov 16, 2010 3:31 am
Location: Latrobe Pa.

if you use a double layer of clear plastic seperated by a inch air space it would hold heat longer. Also insulate the north side of the soil and I bet the temp gain will be 5 degrees higher! Nice design!
I enjoy fishing ,gardening and a solar greenhouse! carpet installation repair and sales for over 45 years! I am the inventor of the Bobber With A Brain - Fishing Bobber!

bogydave
Senior Member
Posts: 197
Joined: Thu Apr 28, 2011 3:11 am
Location: Alaska

Thanks:
some good ideas. Looks like I still have room to experiment farther.
Got me thinking of adding windows to the south side of the angle sided wooden soil beds. a few degrees can do wonder to plant growth & production. :)
pic of garden last spring , just planted :
[img]https://i274.photobucket.com/albums/jj269/bogydave/100_4849.jpg[/img]
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