How to Heat a Greenhouse Without Electricity

it's a common misconception that greenhouses get hot and stay hot with very little effort but that's not the case especially in a cold region like mine in Colorado my Greenhouse warms up just fine during the day and then it's easy to lose all of that heat at night join me today as I show you how to keep an unheated Greenhouse warm [Music] thank you [Music] hi I'm Gardener Scott and as I showed in an earlier video a greenhouse that most of us would have in our garden is just an insulated structure if it gets hot the insulation like these polycarbonate panels of mine will help hold in that heat to a point but when it gets cold in the greenhouse that same insulation can help hold in the cold and for those of us that don't have electricity in our greenhouse and don't have any type of supplemental heating we have to do all we can to try to retain the heat that we do have and that's when we start talking about thermal Mass thermal mass is simply the ability of a material to absorb retain and then release heat and we can see examples of this all around us you've probably walked Barefoot on a concrete sidewalk during the middle of summer and burns your feet because it's so hot concrete is pretty effective at absorbing and retaining and releasing heat that's one reason why I've got these concrete pavers in the greenhouse it's for the purpose of that thermal Mass warming the greenhouse gravel is also pretty effective Rock will absorb retain and release heat but the most efficient thermal mass that we can put in our Greenhouse is water knowing that water is the most efficient thermal Mass to have in an unheated Greenhouse to help keep it warm it's just the first part of the solution we have to figure out how much water we need in the greenhouse to get that heat there are a couple ways to do this the first is to figure out the square footage that you have the sun shining through how much polycarbonate or glass or plastic do you have for the sun's Rays to heat the greenhouse another option is to measure the square footage of the floor of your Greenhouse now my Greenhouse is three meters wide by four meters long and that's pretty close to how much sun exposure I have a little bit less than three meters by four meters and I think a lot of us are going to have similar styles of greenhouses so either formula will give me a basic guideline for how much water I need to put in my Greenhouse to get that thermal Mass positive effect I've done the math and the square footage of my floor is about 130 square feet the square footage of the wall that the sun is shining through is a little bit less than that we're going to take that square footage and multiply it by another factor to determine how many gallons of water we should store in our greenhouse and that factor is going to be determined by how cold your region is and how long your winter is if you're using the method of the surface area that the sun is shining through you multiply the square footage by a factor of two to three if you're using the square footage of your floor then you multiply the factor by two to four in very mild regions where you might only have a couple months of winter you use the lower number in regions where you have harsher weather in longer Winters you use the higher number the square footage of the floor multiplied either by two 260 gallons or three 390 gallons is the target range of how much water I should be storing in my Greenhouse there are other considerations before you arrive at a final number do you have concrete that is also acting as a thermal Mass do you have gravel that's also acting as a thermal mask and how much are you using your Greenhouse if you're not actively growing in it during those coldest months then you don't need as much thermal Mass to heat your Greenhouse if you're only heating the greenhouse during the months where the weather is cool then you don't need as much water I'm not growing in my Greenhouse in the dead of winter so I'm airing on the low side closer to 260 gallons and I've started with these 55 gallon drums and filled them with water and I've added water to these 27 gallon totes giving me another 54 gallons of water now the biggest problem with using water as a thermal mass in your Greenhouse is it can take up an awful lot of space you've probably already noticed that this wall is lined with water I can't grow plants where I have that water stored but I need it to help heat my Greenhouse between the three barrels and these two totes I have 219 gallons of water stored toward my target of 260 gallons to give me some of that extra water storage that I need I'm using gallon jugs and these four gallon cake frosting containers that I got at my supermarket I've painted these containers black the black color will help them absorb and hold the Heat and then gradually release it when it's cool inside I can do the same with the gallon milk jugs and then slide them into every nook and cranny I can find and fill up some of the space that's not being used with the jugs and the containers that I've already painted and filled I'm up to 234 gallons of water and I have more containers to paint and fill and should be able to get up to that 260 gallon Target so the water the concrete pavers and the gravel are all thermal Mass to help keep my Greenhouse warm I've also added a layer of Styrofoam insulation on the north side of this greenhouse one of the reasons it gets so cold in a greenhouse at night is that that heat escapes this extra layer of insulation will help hold in the Heat and because of this reflective surface all this water can radiate its heat back to where the plants are going to be you're probably wondering if I've noticed yet if all of this work is having its desired effect and yes it is my Knights are still getting down to 30 degrees to 40 degrees Fahrenheit but I've noticed even though I don't have as much water as I would like that the temperatures at night are at least 10 degrees Fahrenheit warmer than the outside air temperature so it is staying warmer in here and not getting as cold as it did in that earlier video where this basically becomes a refrigerator and just keeps everything cold what I haven't noticed yet is the effect that this thermal Mass has on cooling the greenhouse because during the heat of the day in summer that's yet to come this water is absorbing the heat that could otherwise overheat the plants so not only does it warm up the greenhouse when it's cold outside but it can actually cool the greenhouse to a point when it's hot outside I'll continue to add water I'd like to get more than that 260 gallon Target and then start doing some real good analysis to see exactly what the Improvement is in the daytime and the nighttime temperatures so you can expect that that video is coming in the future if you want to see what else I've done in my journey towards Greenhouse growing then go ahead and watch this video next I'm Gardener Scott enjoy gardening 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Channel: Gardener Scott

Views: 151,286

Keywords: gardener scott, gardner scott, greenhouse heat, heat a greenhouse, heat unheated greenhouse, greenhouse warming, thermal mass heat storage, thermal mass greenhouse, greenhouse water heating, greenhouse heating, greenhouse heating ideas, greenhouse heating in winter, greenhouse heating without electricity, heat a greenhouse in winter, heat a greenhouse without electricity, how to heat a small greenhouse, how to naturally heat a greenhouse

Id: lU7cvF_mxyk

Length: 9min 53sec (593 seconds)

Published: Thu May 11 2023