[Lester Beans]

They are very easy and cheap to build. I'm currently beginning a build to test a design my engineer father and I have come up with. The hardest part is finding a 55 gal metal drum with lid. Found one at recycling center for free so I'm pumped.

My whole idea is to have plenty of thermal mass and a hot tub.

I live where the winter in 8 months of fucking cold so it has to be a burly mofo.

I would like to circulate water through my beds like radiant heat via the rocket mass.

Permies has the most info.

Yes you can use concrete or bricks instead of cob. I live where clay is prevalent so cob is very practical.

[chronosync]

What about thermal actuators? Greenhouse window openers, I think they're called, some are adjustable to temperatures and some are rated I believe. Vents and fans on thermo and humidistats seem like they would be really important and something I need to learn more about.

Great thread, thanks for starting it plantin plants!, I've never heard of a rocket mass heater before either, thanks Lester!

I'm going to have to check it out I've always thought about growing outside in a shed or something all year round, off grid.

[shredGnar]

Not a greenhouse guy, but couldn't you just run a dehuey to control humidity and use no ventilation while the lights are out? That's how I do my indoor grows...

[plantingplants]

I talked to a friend who ran a greenhouse in winter with lights. He said he just opened up the sides sometmes, kept it warm with lights and a propane burner, and that was it....

[growingcrazy]

What is your humidity outside in the winter in your area? Is it actually going to be a concern?

Solar heated water pumped through pex buried under your beds would keep them warm and could use no moving parts depending on the lay of your land.

I would go solar hot water with a rocket stove backup for really cold nights and some co2.

I know of a couple larger hoops that are heated this way. 4x12 solar exchangers outside and a rocket stove that has the "chimney" or exhaust pipe buried under the beds then exiting. 1 rocket stove per 4 x 16 bed. Collect sticks and yard debris all summer and do one good burn at dusk in the evening all winter.

[plantingplants]

I was just imagining transpiring plants in a warm greenhouse and cold outside being really wet.. plus the rain. The temps at their lowest are around 30F. Like I said, no indoor experience so I don't know how enclosed spaces work.

Anyway, I guess I just have to try this out and see what the humidity does and adjust from there. I just wanted to make sure there was nothing crazy to account for that will turn into a headache.

[maxmurder]

i'm also trying to figure out heat for my 18x44' gh. i have some friends who have much bigger gh's and they've been using radiant/hydronic - they run pex (like someone above said) in the concrete and some sort of water heater to pump thru pex. i like this idea but am renting and pouring concrete won't work. i've been thinking about using sand instead of concrete.
i already have to empty everything out and get a bobcat in there to level out the ground for the auto dep i want to put in. i also need to cover the ground with 1/4" mesh due to gophers and moles, so i wanna do the mesh, then an inch or 2 of sand, the pex, 2 more inches sand, then old dep tarps for vapor barrier, then 3" pea gravel.
i'm using 3 gallon pots in old 10x20" prop trays for saucers so roots don't grow into gravel/sand and run off will be in tray not going into ground.
i was thinking about using a propane tankless water heater to heat and move the water in the pex.
i'm running a driz air 3500 dehumi
https://www.amazon.com/Dri-Eaz-33-ga...A9178224A67ATZ
which helps with heat and humidity but need another one for sure.
any condensation on the inside of the gh skin will rain on plants when the wind picks up.

[maxmurder]

actually i just realized the tankless doesn't move the water in my house, water pressure does.
this is recirculating in the gh so i gotta figure out a pump.
sure does help typing this shit out hahahaah.

planting- are you just gonna blast your light to extend photoperiod or are you gonna cover so neighbors don't see??

[plantingplants]

Yea no way I can do beds so no way I can pump hot water. A friend told me you can compost wood chips with inoculant and make a compost heater to heat water.

I made a mistake buying the 70 pint GE. I'm going to get a proper dehumidifier.

I'll use the 1k to veg but also in flower. Just going to keep it covered constantly for warmth. Neighbors can't see it but my windows can so I'm thinking it makes a lot more sense to just get heavy duty light blocking curtains than to pull a tarp just for the light.

It's within the ordinance too.

[ronbo51]

This thread has evolved from its beginnings on ventilating a cold weather greenhouse to a broader discussion of heating/ventilating a winter greenhouse. I had greenhouses in Maine and heated with wood. I had lots of it. It was free in a minus the value of my labor sort of way. I could control humidity by putting a large pot of water on the stovetop to steam away, or not, depending. Wood heat is drying, as opposed to propane, which adds moisture to a large amount. Propane is your other alternative. Get the biggest tank you can and hook up a bigass heater and be done with it. Can you run a greenhouse as a sealed room? Don't ventilate. Control moisture with wood heat and add co2. Or use propane which adds co2 and run a dehuey. I council against buried pex and hot water. Pex is a lousy transmitter of heat. I played around alot with hot water solar panels in Maine. Without the density of concrete radiant will not work very well.

Also a cycle timer can be hooked to a fan and be programmed to come on for 30 seconds at whatever intervals to ventilate