Compost-Heated Greenhouse: Making Use of Kitchen Scraps

In sustainable gardening, the concept of a compost-heated greenhouse represents a remarkable fusion of eco-friendliness and efficiency. At its core, this innovative approach transforms organic kitchen waste into a rich source of heat for plants. 

By using a compost-heated greenhouse, you’re not just giving your plants a cozy place to thrive. You’re also actively reducing waste, lessening the burden on landfills, and contributing to a healthier planet. Think about it: your everyday banana peels and coffee grounds could be the secret ingredient to a flourishing garden.  Let’s explore how your kitchen scraps can turn into an efficient and eco-friendly heat source for your garden sanctuary.

Understanding the Compost Heated Greenhouse

What is a Compost Heated Greenhouse?

A compost-heated greenhouse operates on a simple yet ingenious principle. At its heart is the process of composting, where organic matter like kitchen waste decomposes. This natural process is not just a transformation of waste into nutrient-rich compost, but it’s also an exothermic reaction – meaning it releases heat. In a compost-heated greenhouse, this heat maintains a warm environment for plants. As microorganisms break down the organic matter, they generate heat to keep the greenhouse warm. This process is a perfect mix of biology and sustainability, turning waste into a valuable resource.

Benefits of Using a Compost-Heated Greenhouse

benefits of using a compost-heated greenhouse
  • Sustainable Heating Source: The heat generated from composting is renewable and reduces reliance on fossil fuels.
  • Waste Reduction: Utilizes kitchen scraps and garden waste, minimizing household waste and lowering landfill contributions.
  • Cost-Effective: Reduces heating costs, as the natural process of composting provides a free heat source.
  • Enhanced Plant Growth: Provides a stable, warm environment, which is ideal for extending growing seasons, especially in colder climates.
  • Soil Improvement: Over time, the compost can enrich the soil, boosting its nutrient content and overall health.
  • Eco-Friendly: Lowers carbon footprint, contributing to environmental conservation efforts.
  • Educational Opportunity: Composting is great for teaching about sustainable practices and ecology.

By integrating these benefits, a compost-heated greenhouse is not just a gardening tool; it’s a step towards a more sustainable and eco-conscious way of living.

The Science Behind Compost-Heated Greenhouses

How Composting Generates Heat

The heat generation in a compost-heated greenhouse stems from the microbiological activity within the compost. When organic material, such as kitchen scraps, decomposes, it becomes a hotbed for microorganisms like bacteria and fungi. These tiny organisms break down the organic matter during aerobic decomposition, which requires oxygen. As they consume the material, they release energy in the form of heat.

The heat is a byproduct of the microorganisms metabolizing the carbon and nitrogen-rich materials in the compost pile. The more active the decomposition, the more heat is produced to maintain a balanced mix of ‘greens’ (like vegetable scraps, rich in nitrogen) and ‘browns’ (like dry leaves or straw, high in carbon). This balance keeps the microorganisms happy and working efficiently. The science of composting is fascinating, as it converts waste into a valuable resource through natural biological processes.

Maintaining Optimal Temperatures for Plant Growth

In a compost-heated greenhouse, the key is generating heat and maintaining it at a level conducive to plant growth. Plants thrive in a consistent and warm environment, especially in regions with cooler climates. The ideal temperature range varies depending on the plants you’re growing, but generally, maintaining the greenhouse at around 65-75°F (18-24°C) benefits the plants. Temperature monitoring is crucial; too much heat can be as detrimental as too little. By striking the right balance, your compost-heated greenhouse can become a year-round haven for plants.

Preparing Your Kitchen Scraps for the Compost-Heated Greenhouse

kitchen wastes for composting

Types of Kitchen Waste Suitable for Composting

It’s important to know what kitchen waste works best for composting to maximize the efficiency of your compost-heated greenhouse. Here’s a quick list:

  • Fruit and Vegetable Scraps: Apple cores, banana peels, carrot tops, and similar items.
  • Coffee Grounds and Filters: A great source of nitrogen.
  • Eggshells: Crushed eggshells add calcium to the compost.
  • Tea Bags: Make sure they are not synthetic fibers.
  • Bread and Grains: In moderation, as they can attract pests.
  • Nut Shells: Except for walnut shells, which can be toxic to some plants.
  • Rice and Pasta: In small amounts, to avoid attracting rodents.

Avoid adding meat, dairy, oils, and diseased plant materials, as these can create odor problems, attract pests, and potentially harm your compost’s balance.

Tips for Efficient Composting

Efficient composting is vital to a successful compost-heated greenhouse. Here are some tips to get you started:

  • Balance ‘Greens’ and ‘Browns’: Mix nitrogen-rich ‘greens’ (like vegetable scraps) with carbon-rich ‘browns’ (like dry leaves or newspaper).
  • Cut or Break Down Large Pieces: Smaller pieces decompose faster.
  • Maintain Moisture: Your compost should be moist but not soggy.
  • Regular Turning: This aerates the compost, speeding up the process and generating more heat.
  • Monitor the Temperature: Aim for a compost temperature between 130-160°F (55-70°C) for optimal heat production.
  • Keep it Covered: This retains heat and moisture and prevents over-drying.
  • Avoid Overloading with Citrus or Onions: These can be too acidic. Additionally, they might slow the composting process.

These guidelines can turn your kitchen waste into a valuable resource for your compost-heated greenhouse.

Building Your Compost-Heated Greenhouse

Basic Design and Materials Needed

Creating your compost-heated greenhouse starts with understanding the basic design and gathering the necessary materials. The design centers around a space that can efficiently retain heat generated by the compost. Key materials include:

  • Structural Framework: Usually wood or metal for the greenhouse frame.
  • Transparent Covering: Glass or clear plastic sheeting to allow sunlight and retain warmth.
  • Insulation: Materials like straw bales or foam insulation for walls and floors to keep heat in.
  • Compost Bins or Area: Designated space for compost, ideally close to the greenhouse to maximize heat transfer.
  • Thermometer: To monitor the temperature inside the compost and the greenhouse.
  • Ventilation System: Vents or fans to regulate temperature and humidity.
  • Watering System: For maintaining plant and compost moisture levels.
  • Tools and Supplies: Basic gardening tools, screws, nails, and other construction materials.

These materials form the backbone of your compost-heated greenhouse, setting the stage for a successful build.

Step-by-Step Construction Process

  1. Plan Your Layout: Decide the size and location of your greenhouse, considering sunlight exposure and proximity to compost.
  2. Build the Frame: Construct the frame using your chosen material, ensuring it’s sturdy and weather-resistant.
  3. Install the Covering: Attach the transparent covering to let in sunlight while trapping heat.
  4. Set Up Insulation: Insulate the walls and, possibly, the floor to retain heat.
  5. Arrange Compost Area: Position your compost bins or designated composting area near or inside the greenhouse for optimal heat use.
  6. Install Ventilation: Add vents or fans to control the internal climate.
  7. Set Up Watering System: Implement an irrigation system for your plants.
  8. Place a Thermometer: Install thermometers to monitor the temperatures of both the compost and the greenhouse interior.
  9. Add Plants: Once the structure is ready, start adding your plants.
  10. Regular Maintenance: Always check the structure, compost, and plants for any needed adjustments or maintenance.

Building your compost-heated greenhouse can be a rewarding DIY project, offering a sustainable way to grow plants year-round. With careful planning and execution, you can create a warm, eco-friendly environment for your garden.

Managing Your Compost-Heated Greenhouse

Regular Maintenance Tips

Regular maintenance is important to ensure your compost-heated greenhouse operates efficiently. Here are some essential tips:

  • Compost Care: Regularly turn your compost to facilitate decomposition and consistent heat production. Also, keep adding fresh organic material to keep the compost active.
  • Inspect for Damage: Check the structure periodically for any damage or wear, especially after extreme weather conditions.
  • Clean the Covering: Keep the covering clean to ensure maximum sunlight penetration.
  • Pest and Disease Control: Monitor for any signs of pests or diseases among your plants and address them promptly to prevent spread.
  • Watering: Adjust your watering schedule as needed, ensuring plants receive adequate moisture without overwatering.
  • Soil Health: Regularly check the soil for nutrient levels and moisture content, and add compost or other organic matter as needed.

These practices will help maintain a healthy and productive environment in your compost-heated greenhouse.

Monitoring and Adjusting Heat Levels

Maintaining the correct temperature is crucial in a compost-heated greenhouse. Here’s how you can monitor and adjust the heat levels:

  • Use Thermometers: Place thermometers in different areas of the greenhouse to get a comprehensive understanding of the internal temperature.
  • Adjust Compost Quantity: Increase or decrease the amount of compost to regulate heat production. More compost means more heat.
  • Ventilation Management: Use vents or fans to release excess heat and maintain a stable temperature inside the greenhouse.
  • Insulation Checks: Ensure that the insulation is intact and effective in retaining heat, especially during colder months.
  • Sunlight Management: During warmer seasons, use shade cloths to prevent overheating.

By actively monitoring and adjusting these elements, you can maintain an optimal growing environment in your compost-heated greenhouse throughout the year.

Maximizing Plant Growth in Your Compost-Heated Greenhouse

Achieving optimal plant growth in your compost-heated greenhouse involves careful plant selection and cultivation practices. Here are some best practices to consider:

  1. Choose the Right Plants: Opt for plants that thrive in warm environments. Vegetables like tomatoes, cucumbers, and peppers, as well as herbs and some flower varieties, are ideal choices.
  2. Understand Plant Needs: Different plants require varying levels of humidity, light, and heat. Research your plants’ specific needs for the best results.
  3. Soil Quality: Use high-quality, nutrient-rich soil. Incorporate compost from your heap to enhance soil fertility.
  4. Consistent Watering: Maintain a regular watering schedule. Overwatering can be as harmful as under-watering, so ensure the soil is moist but not waterlogged.
  5. Pruning and Spacing: Regularly prune your plants to encourage healthy growth and ensure they have enough space to grow without competing for resources.

By following these guidelines, you can create a thriving environment in your compost-heated greenhouse, leading to healthy, robust plant growth.


The journey through the world of compost-heated greenhouses reveals a harmonious blend of sustainability, innovation, and practicality. These greenhouses represent more than just a gardening technique; they are a testament to our ability to harness nature’s processes for eco-friendly solutions. By recycling kitchen waste into a valuable heat source, we reduce our environmental impact while enhancing our gardening experience. The benefits, ranging from extended growing seasons to reduced carbon footprints, underscore the importance of adopting such sustainable practices. Embracing compost-heated greenhouses is a step forward in our collective effort towards a more environmentally conscious and self-sustaining future.

Frequently Asked Questions (FAQs)

Q1: What exactly is a compost-heated greenhouse?

A compost-heated greenhouse is a sustainable gardening structure where heat generated from composting organic matter, such as kitchen scraps, is used to maintain a warm environment for plants. It leverages the natural heat produced during the composting process to extend the growing season, especially in cooler climates.

Q2: How much does it cost to build a compost-heated greenhouse?

The cost can vary greatly depending on the size, materials, and design complexity. A basic, small-scale DIY project might cost a few hundred dollars, while larger, more elaborate setups could cost more. The main expenses include the framework, transparent covering, insulation materials, and compost bins.

Q3: What types of plants grow well in a compost-heated greenhouse?

Most plants that thrive in warm environments will do well. This includes vegetables like tomatoes, peppers, and leafy greens, as well as herbs and flowers. The key is to monitor and maintain the right temperature and humidity levels.

Q4: Is a compost-heated greenhouse environmentally friendly?

Absolutely. It reduces waste by recycling kitchen scraps, minimizes reliance on artificial heating sources, and lowers your carbon footprint, making it a highly sustainable option for gardeners.

Q5: Can I build a compost-heated greenhouse on a small scale, like in my backyard?

Yes, compost-heated greenhouses can be built on a small scale and are perfect for backyard gardeners. The design can be scaled down to fit the available space while still providing the benefits of a traditional greenhouse.

compost-heated greenhouse
grant yost greenhouse innovator

Grant Yost

Grant Yost is co-owner of Beulah Land Farms, a small business that is part of and trying to push forward the local food movement. Although I grew up on a farm in the middle of Kansas, we took the wheat and other grain to the elevator, and then went to the grocery store to buy all our food. Maybe it's a generational thing, but we should be growing our own food as much as possible! My wife was diagnosed with Graves disease, which is an auto-immune disease affecting the thyroid, and while it wasn't debilitating (we are grateful for that) we have to wonder if it had to do with processed food and our mass-produced food supply. Auto-immune epidemic anyone? Also, maybe a generational thing... we live in the city in Kansas City, but our kids want to move to the farm!

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