Gardening with a greenhouse can be incredibly rewarding — but only when your soil works with you, not against you. If your plants are growing slowly, producing underwhelming yields, or showing signs of disease or stress, your soil might be the culprit.
Many greenhouse gardeners don’t realize that even the most advanced lighting and watering systems can’t compensate for poor soil quality.
The good news? There’s a natural, budget-friendly solution that transforms tired soil into a thriving ecosystem for your plants: composting.
Not only can compost improve soil health, but it can also help heat your greenhouse. Your food scraps and yard waste can become both a superfood for your soil and a sustainable source of warmth for your growing space.
Let’s dig into how a compost-heated greenhouse can save you money and help your plants thrive.
At its core, composting is the natural process of recycling organic materials, like kitchen scraps and yard clippings, into rich, dark humus packed with nutrients.
Microorganisms, fungi, and even worms break down this organic matter, creating a powerful, all-natural soil.
Why compost in your greenhouse?
Starting your own compost system is easier than you might think, and you can do it inside your greenhouse or just outside the walls for easy access.
Pro Tip: A compost thermometer is a handy tool to ensure the pile is heating up properly, especially if you’re counting on it as a supplemental heat source.
Not all waste is compostable. Here’s what to include, and what to avoid, for a productive pile.
Aim for a ratio of 2–3 parts brown to 1 part green to keep your pile balanced and odor-free.
Browns (like dried leaves, cardboard, or straw) provide carbon, which helps absorb moisture and reduce smells, while greens (like fruit scraps or grass clippings) add nitrogen, which fuels microbial activity.
Too much green can make your pile soggy and smelly; too much brown can slow the composting process. If your pile smells like ammonia, add more browns. If it’s dry and not breaking down, mix in more greens.
When you’re gardening with a greenhouse by utilizing composting, striking the right balance keeps the decomposition process active and your compost healthy.
There are two main composting approaches that work well in greenhouse settings.
This involves using red wigglers to break down food waste in a worm bin. It's ideal for small-scale greenhouse setups or gardeners with limited space, as worm bins can be kept indoors or in a shaded greenhouse corner.
Vermicompost is rich in nutrients and beneficial microbes, making it a powerful soil amendment. Plus, it’s nearly odorless and requires minimal maintenance once established.
A traditional, fast method where microbial activity generates high heat (130–160°F). This high temperature helps kill weed seeds and pathogens, producing finished compost in as little as 4–6 weeks.
Hot composting works best with larger piles and consistent turning to maintain heat and airflow. It’s a great option for gardeners who want a compost-heated greenhouse, need large volumes of compost quickly, and have access to plenty of materials.
Here’s the unexpected bonus of composting: it naturally produces heat as materials decompose. If managed properly, a compost pile can reach internal temperatures over 140°F — perfect for providing supplemental warmth to a greenhouse in colder months.
A compost-heated greenhouse won’t fully replace traditional heating systems, but it can lower energy bills, extend your growing season, and support a more self-sustaining garden.
Even the most passionate gardeners make composting mistakes—but they’re easy to fix.
When in doubt, remember the composting basics: balance, moisture, and air.
Once your compost is dark, crumbly, and earthy-smelling, it’s ready to use!
Adding compost regularly will strengthen plant roots, improve drainage, and reduce the need for chemical fertilizers, all while reusing your household and garden waste.
Composting is one of the most powerful, affordable tools you can use when gardening with a greenhouse. It improves your soil and boosts yields, but it can also help heat your greenhouse and reduce waste in the process.
Whether you’re a weekend gardener or growing year-round, starting a compost system is a step toward healthier plants, lower gardening costs, and a compost-heated greenhouse.
Want to dive deeper into gardening with a greenhouse? Download our free guide, "Beginner’s Guide to Greenhouse Gardening," and unlock even more tips to help your garden thrive.