The most economical way to heat a small greenhouse to keep it warm overnight is to capture solar heat in mass.
The denser and darker the mass, the more heat it can absorb. Stone, tile, brick, water jugs, black painted cinder blocks and drums are all possibilities for storing heat mass.
We’ve added some of these to our cattle panel greenhouse. We view this also as an opportunity to learn through trial and error on a small scale as preparation for when we have space for a larger greenhouse.
Heat a Small Greenhouse
In summary, here are tools and resources for heating a greenhouse:
- Pathways, edgings and supports:
- stones
- gravel
- brick
- tile
- black painted cinder blocks
- Space heaters:
- radiant
- propane
- ceramic
- Water:
- jugs
- barrels
Greenhouse Heaters We’re Using
We’re currently using two radiant heaters a one small ceramic heater for our little cattle panel greenhouse.
For temps into the 20’s ℉, these are working fine. We’re tracking the day and night temps regularly using a handy wireless greenhouse thermometer, which is working great and saves a lot of time in checking manually.
Propane Heater for Power Outages
There are occasional electrical outages during the winter months, and they render our electric heaters useless. As a backup, we have a Mr. Heater “Buddy” type propane heater which runs off a 1# canisters or an accessory hose attached to a 20# LP tank.
Heating a Greenhouse with Water
We nabbed one of our dormant rain barrels and set it up on black painted blocks at the rear end of the greenhouse. The rain barrel is dark brown and holds 50 gallons of water. There’s a hose bib tap at the bottom and that supplies water for the plants. The back side is also flat so it takes up less space.
The rain barrel provides heat storage and a water source all in one unit. It will require occasional filling with a hose run up from the house. We’ll keep a hose handy and fill the barrel as needed.
By elevating the rain barrel with dark blocks we’ve added a heat collection source, while making the spigot accessible for filling our watering can.
The next thing we could do to improve our solar energy retention is to add dark gravel to the walkway.
Wishing you great gardens and happy harvests!
I’m LeAura Alderson, a garden, herb and plant enthusiast with a passion for discovering the many edible and medicinal benefits of the plants all around us, including the weeds! I’m a writer, editor and media publisher for our family of websites.
While I was certified in fitness and life coaching, I am NOT a health practitioner. However, I’m a lifelong health enthusiast, with a keen interest in healthy, organic foods and making home remedies and the content we share is from our own experience and usage as well as that extracted from scientific research so that you can explore further on your own.
Always seek the advice and guidance of your health practitioners first and foremost.
As a family we’re steadily expanding our gardening, experimentation and knowledge around all things gardening, edible landscaping, fresh organic foods and self sustainability with farming in our future. I also own and manage iCreateDaily.com, a site all about transformation through creation, and the power of positivity, optimism and mindset.