Cheapest Way to Heat a Greenhouse: How to Heat a Greenhouse in Winter for Free?

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Cheap Ways To Heat A Greenhouse Without Electricity

The astronomical monies involved with some of the traditional greenhouse heating methods have led researchers to relentlessly pursue pocket-friendly alternatives…..especially with farmers eagerly awaiting the invention of the cheapest way to heat a greenhouse.

We have also been on a similar mission here at ..although we choose to go a step further- and also find out how to heat a greenhouse in winter for free.

Well, the good news is that we have already come across some functional money-saving options.

Paraffin heaters, compost, Bubble wrap, DIY systems, and thermal mass are just some of the effective and cheaper greenhouse heating methods.

Here now are our insights into how to heat a greenhouse in winter for free (or almost free).


Click Here For The Best Greenhouse Heaters
Click Here For The Best Horticultural Fleece/Plant Covers/Plant Blankets
Click Here For The Best Useful Greenhouse Products & Parts & Accessories

A. Compost For Warmth – Heating A Greenhouse with Compost

Compost is one important input for gardeners.

Beyond nourishing your plantation with essential nutrients, compost has another major advantage: heat

This is what happens:

As it chemically dissolves, compost releases energy as heat. This can even rise above 1000F

As such, your plants can benefit a lot from manure during the winter.

The sweetest news is that heating a greenhouse with compost is almost 100% free- if you know how to prepare it

And in case you are unsure of how to use compost to create a powerful water heater, here is a nice guide.

The Compost-Powered Greenhouse Heater: Heat A Greenhouse Using Compost

Author Gaelan Brown in collaboration with engineers and top compost experts has researched and written a very informative manual on the various refined ways of composting.

If you are looking at using manure to heat your greenhouses, this is a complete trainer.

It trains you how to make high-value compost organically while generating reasonable combustion-free heat.

And it’s very practical thanks to the numerous case studies, step-by-step illustrations plus photos

So, if you are thinking long-term cheap greenhouse heating, this could prove to be a smart investment.

Editor’s Note:

Follow this manual 100% …you should soon be enjoying free heating!


Click Here For The Best Compost Products For Greenhouses

B. Store Solar-based Energy In A Thermal Mass

Another cheap and common way to heat a greenhouse is to utilize thermal mass (sometimes called a heat sink).

A thermal mass is simply any material that can store thermal energy until the temperatures decline when it will start releasing the stored heat into your greenhouse.

When selecting, choose the right material – that’s because some hold heat better than others.

For instance, water holds roughly 2 times the heat that concrete holds, and as much as 4 times what soil holds and is most preferred.

Using Water As A Thermal Mass

Water barrels are excellent when used as thermal mass due to their higher heat capacity.

You can fill a reasonable number of 55-gallon drums with water then stack them on each other.

You will have created an energetic thermal mass.

Ensure you stack the barrels where they can access direct sunlight- mostly facing south.

Also,put them near tender plants since they need more warmth when the temperature drops off.

Alternative Materials

If the floors of your greenhouse have been made from compressed gravel or concrete, then you already have your thermal mass.

Also, the soil in your raised seedbeds can also add thermal mass.

Another thing, if you have been growing using an aquaponics system — where fish and plants grow symbiotically —the fish tanks can double as thermal mass.


Click Here For The Best Water Barrels For Greenhouses

C. Insulation

The simplest way to protect your plants from cold is by insulating.

Depending on your budget and what you’re cultivating, you can insulate with either:

  • A regular bubble wrap
  • A Horticultural bubble wrap
  • A horticultural fleece
  • A Regular Bubble Wrap

Covering your greenhouse with a layer of insulating bubble wrap helps.

A bubble wrap functions as an added shield against frost beside restraining the heat inside.

For wooden greenhouses, you can use push pins to fasten the wrap against the wall.

If your housing is metallic, use special fasteners to twist it the frame.

In case your glazing is glass, moisten suction cups and press them against it –they should work. Once you wrap up all the walls plus the roofing, don’t forget to seal any wrap joints with scotch tape- this avoids potential heat loss.

Remember you’ll need to ventilate your greenhouse.

So be sure to line the vents separately (or at least one) to allow them/it to open.

This trick works wonders for both heated and unheated greenhouses.


Click Here For The Best Bubble Wraps

  • A Horticultural Bubble Wrap

You can also choose to take the horticultural bubble wrap route- these types of wrappers are considered tougher, longer lasting, and are UV-stabilized.

And they definitely give better results.

To give you a better idea of how these work, here is a review of the most recommended horticultural bubble wraps

1. Duck Brand Original Protective Horticultural Bubble Wrap – Single Roll

This features a unique air lock technology and is revered for its ability to maintain consistent cushioning against freeze.

It’s also one of the longest lasting and so you will use it for many more winters.

When installing, it wonderfully conforms to your walls and even awkward corners.

With its outstanding air lock technology helping to reliably guard against the freeze, this could be an amazing gift for your crops.

Remember you can also use it for many other purposes at home

  • Conforms easily around awkward corners
  • Hold heat longer hence protect your herbs better
  • Easy to install
  • Smaller size bubbles

2. Reflectix Staple Tab Horticultural Insulation Roll

This has a special construction.

It has twin layers of toughened aluminum foil that reflects as much as 97% of radiant heat.

The center layer is made of polyethylene thus making it more reliable and stronger.

It’s therefore perfect in insulating greenhouses using radiant heating systems.

Thicker and with a reinforced construction, this does well to insulate radiantly heated greenhouses

It’s considered a reliable and cost-effective greenhouse heating solution.

Editor’s Note:

Finally when the cold is gone, carefully take down the bubble and store it- next winter will find you fully armed.

  • Easy to cut and wrap
  • Made of Non-toxic (Fiber free)
  • Very durable
  • Doesn’t come with staple tabs


Click Here For The Best Horticultural Bubble Wraps

  • A Horticultural Fleece

Moving away from the bubble wrap and the horticultural fleece, another handy option is by covering your suffering plants using a horticultural fleece.

This is particularly recommended as an additional insulation during those nights when it’s extra-cold

As usual with covers, remember to remove your fleece during daytime to afford your veggies a chance to breathe and also to receive essential light


Click Here For The Best Horticultural Fleece/Plant Covers/Plant Blankets

  • Use an Economical Renewable Energy Powered Heater

Harnessing the sun and storing solar energy is your first step towards‘free’ heating.

But if you need additional heating, the underrated rocket mass heater could offer a fantastic solution

If you ask those who have used it, they will tell you that this is a super-efficient improvisation from an ordinary wood stove.

This is what it does:

Rather than exhaust hot air straight through the chimney like standard wood stoves do, this customized wood stove will first circulate the hot air past a mass of brick,cob, or even stone before being exhausted out.

The air will warm the mass, hold the heat before subsequently radiating it back into your greenhouse.

It will continue warming even if your stove is no longer burning.

A rocket mass heater is mainly a DIY system; you will need to investigate the appropriate design for your greenhouse from the many plans and explanations available online.

One can also consider cheap grow light bulbs for indoor plants.

Looking at the options, we can say that the search for the cheapest way to heat a greenhouse has been quite successful.

But rather than stick to one method, it’s recommended that you experiment and see what works for you. The good thing is that even if not all are 100% free- some of you had actually asked how to heat a greenhouse in winter for free – the little investment in terms of labor, time, and materials pays back big in the long run.

Otherwise, this is clear evidence that you don’t have to burn a hole in your pocket to grow food in a greenhouse.


Click Here For The Best Greenhouse Heaters


Click Here For The Best Useful Greenhouse Products & Parts & Accessories

D. Heating Your Greenhouse Using Paraffin

A paraffin heater can supply the warmth your plants are desperate for during winter.

Provided your greenhouse doesn’t extend more 8ft in length, you will find paraffin powered energy convenient.

Also, mind the following:

  • Heating demand should not be too high(maximum of +5c )
  • Outside temperature should not go below -6c

With these conditions, your paraffin heater greenhousewill readily save your herbs from the biting cold.

Where To Buy Paraffin Greenhouse Geaters?

You can buy a good paraffin heater from the teeming online stores, local garden stores, and in some cases, from manufacturers direct

Paraffin Greenhouse Heaters Reviews 2021

Here are the top paraffin greenhouse heaters from Amazon.

1. Parasene Superwarm Heater

This is ideal for heating a 6ft x 6ft greenhouse. It delivers continuous burning and will help your plants remain super warm despite the chill.

Like other paraffin heaters, it’s cheaper and very easy to use.

This is another functional economical anti-frost heater for small greenhouses. Since it’s so light, you can place it at any preferred spot to maximize results.

  • Works well
  • Highly portable
  • Straightforward application
  • Not for bigger spaces


Click Here For The Best Useful Greenhouse Products & Parts & Accessories

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