Anyone Heat Greenhouse With Solar ?

[Nyboy]

My nephew must have something planed he is on my back about heating greenhouse. So far in 3 years it has only stored lawn furniture cushions. I don't want to spend money on heating. Thinks solar is way to go. Panels are as cheap as $125 not sure what else is needed.

 

[Collector]

Never thought about solar panels, might be a good idea. I think that making the heat is the easy part, holding it in is the trick. The best might be the bubble wrap, but hard to find any wide enough to work. I come up with ideas every spring but it hard to justify putting out a lot of money to gain a couple more months growing imho.

 

[Nyboy]

I was thinking small electric heater run by solar

 

[flowerbug]

Never thought about solar panels, might be a good idea. I think that making the heat is the easy part, holding it in is the trick. The best might be the bubble wrap, but hard to find any wide enough to work. I come up with ideas every spring but it hard to justify putting out a lot of money to gain a couple more months growing imho.

if you can get a chance this is a good start to exploring the issues:

https://www.npr.org/sections/thesal...rmal-greenhouses-grow-local-produce-in-winter

solar panels for electricity are not a great use of heat energy from the sun, better if you can capture the heat directly somehow.

the most general problem is that you must absolutely have a guaranteed power source to have constant heat in the winter. a few nights of no power in -20F and your greenhouse is dead. the costs of having battery backup and power supplies and all that technology is not easy and why many people find it more expensive than is worth it for a few $ of veggies and fruits a week.

if you could get enough people to join a larger coop and then use that as a way to leverage the risk/expenses/expertice/land/etc. well it might pay off, sorta...

geothermal would definitely be the best way to run it and also using the geothermal to generate the electricity you'd need to run the pumps used would be even better, but you'd still want some kind of backup system...

all IMO of course...

 

[Nyboy]

One of our members changed her whole house to geothermal heat. What i have is called a solar shed afraid of snow weight with all glass greenhouse.

 

[Nyboy]

The solid walls I insulated and lined in mylar

 

[digitS']

This is just about the worst place in the US for winter solar - low angle of the sun, short days, and nearly as many winter cloudy days as the PNW coast.

Semi-subterranean may make sense. Forty inches down in the ground, it's about 50° year around, I believe it is. Still, January average daily temperature is right at 30°. So, an average day has above freezing temperatures for about 8 hours. Plants don't do averages. Many die at 32° and it only takes once. Sub-zero winter nights happen, even sub-zero through 24 hours, some winters.

We have quite a lot of hydroelectric power in this part of the world. And, not many ice storms ... Springtime backup for my greenhouse is a propane cookstove, a bag of charcoal and a hibachi. I've never used either and don't run the greenhouse furnace in the winter, anyway.

An Organic Gardening article I read long ago claimed that nearly all glazing material, glass or plastic, reduces light by about 10%. So, doubling reduces 20%, triple glazing 30% ... we already have precious little winter sunlight!

Just growing indoors under lights may make more sense than operating a winter greenhouse. Keep in mind that any valuable plants (hint, hint ) your nephew may have in mind, are not very secure behind transparent walls ...

Steve

 

[flowerbug]

with LEDs being pretty efficient now it may make more sense to go completely underground if you have something like hydropower or wind for electricity...

 

[digitS']

There was a skiff of snow, 4 days ago. It didn't amount to an inch and melted. There is a little snow in the very coolest parts of the yard.

It hasn't been sunny but just above freezing daily, through most daylight hours. It's now pre-dawn, foggy and 26°f. It was 34° yesterday, 37° Sunday afternoon.

The north roof of my greenhouse is a 2 by 4 frame with fiberglass and Styrofoam insulation on the interior. On the exterior, there is snow.

Without the sunshine, the darn thing just doesn't warm up. It loses heat through the plastic film like crazy. Oddly, there is enough protection that right down on the floor, and even after several 20° mornings (hasn't been in the teens, yet) the smallest Thai pepper plants are still alive! The thermometer claims that it's 33° about 4' above the floor.

I'm missing the Asian greens this winter - still planning work on the south wall. You can understand why they can grow in there. All the house plants are back in the house. Maybe I should take pity on a pepper, dig it up and bring it in ...

Steve

 

[Nyboy]

I am trying to over winter 3 window boxes green house well insulated but not heated