Composting In A Greenhouse: Unleashing the Power of Nature’s Gold

  • By: Sam Richards
  • Date: September 5, 2023
  • Time to read: 10 min.

Composting, a revered cornerstone of sustainable gardening, is the art and science of transforming organic waste into nutrient-rich gold for plants. By harnessing the natural process of decomposition, composting recycles once-discarded materials like food scraps, lawn trimmings, and leaves into a soil conditioner teeming with life and fertility. In recent years, the fusion of composting with greenhouse gardening has begun to gain traction. The greenhouse, typically seen as a haven for year-round plant growth, now plays dual roles – fostering plants and decomposing organic matter. When these two processes come together under one roof, the result is an ecosystem that not only enhances plant growth but also epitomizes resourcefulness and environmental stewardship. In this article, we delve into the intricacies of this marriage between composting and greenhouses, exploring its benefits, methods, and the immense potential it holds for gardeners worldwide.

Can You Compost In A Greenhouse?

The notion of composting typically evokes images of open-air heaps or bins, often relegated to a distant corner of a garden. However, have you ever considered the possibility of composting within the controlled environment of a greenhouse? The answer is a resounding “Yes!” Greenhouses, renowned for their ability to modulate temperature and humidity, provide a unique setting for the composting process. These controlled conditions often enable faster and more efficient decomposition compared to the unpredictable outdoors. This not only means accelerated compost production but also the opportunity to compost throughout the year, regardless of external climatic challenges. By harmonizing the benefits of greenhouses with the process of composting, gardeners can craft a continuous cycle of nourishment and growth, right at their fingertips.

Types of Composting Methods Suitable for Greenhouses

Navigating through the myriad of composting methods might feel overwhelming, but when tailored to the specifics of greenhouse environments, certain methods stand out due to their efficiency and practicality. Here’s a deeper look into these methods:

  • Traditional composting: This classic approach involves creating heaps or using bins to accumulate organic waste. Over time, aided by microorganisms and regular turning, these materials break down. Within a greenhouse, this method benefits from a more consistent temperature, which can potentially lead to quicker and more uniform decomposition.
  • Vermicomposting: Here, nature’s diligent workers, worms (especially red wrigglers), are the stars. These worms feast on organic waste, converting it into worm castings – a rich, fine-textured compost. Given a greenhouse’s protection from extreme conditions, worms can work optimally throughout the year, uninterrupted by harsh winters or scorching summers.
  • Bokashi fermentation: This Japanese technique harnesses the power of fermentation. Organic waste is layered with Bokashi bran, which has been fermented with effective microorganisms. Once fermented, this pre-compost can be added to traditional compost heaps or directly to the soil. The greenhouse environment supports consistent fermentation, making the process smoother and more predictable.
  • Green composting: This method places emphasis on nitrogen-rich materials like fresh grass clippings, kitchen scraps, and manure. When these ‘greens’ break down, they release nitrogen, a vital nutrient for plant growth. In a greenhouse, the decomposition of these materials can be closely monitored, ensuring they don’t become overly wet or compacted.
  • Brown composting: Contrasting with green composting, this focuses on carbon-rich materials such as dried leaves, straw, paper, and cardboard. These ‘browns’ are essential for providing structure to the compost and fostering aeration. A greenhouse’s controlled environment ensures that these materials don’t become too dry, preserving the essential microbial activity.

By understanding and leveraging these composting techniques in a greenhouse setting, gardeners can maximize the quality of the compost produced, ensuring their plants receive the best nourishment possible.

How To Compost In A Greenhouse

Composting within the sheltered space of a greenhouse isn’t just a replication of the outdoor process; it’s an enhancement, with the controlled environment optimizing each step. Here’s a more detailed guide to composting effectively within your greenhouse:

  1. Choose a Compost System: Begin by selecting a system that aligns with your needs. This could range from dedicated compost bins, tumblers, or simple compost heaps. Consider the size of your greenhouse and the volume of waste you produce to determine the best fit.
  2. Balance the Materials: One of the keys to successful composting is maintaining a harmonious balance between green (nitrogen-rich) and brown (carbon-rich) materials. Aim for a rough ratio of 2 parts brown to 1 part green. This balance aids in speeding up the decomposition process while preventing unpleasant odors.
  3. Layering for Success: Initiate your compost heap with coarse materials, such as small twigs or straw, at the base to promote airflow. Thereafter, alternate layers of green and brown materials. This layered structure not only enhances aeration but also ensures a diverse microbial population, critical for decomposition.
  4. Regular Maintenance: Turning your compost pile every week or so is crucial. This action introduces air, essential for the microbes to break down the organic matter efficiently. Within a greenhouse, where humidity can be high, turning also helps in preventing the compost from becoming overly soggy.
  5. Monitor Moisture and Temperature: A moist sponge’s consistency is what you’re aiming for with your compost. In the controlled environment of a greenhouse, you have the advantage of adjusting watering to maintain this balance. Additionally, using a compost thermometer can be beneficial. Aim for temperatures between 90°F to 140°F (32°C to 60°C) to foster optimal microbial activity and to expedite the decomposition process.
  6. Patience and Harvest: Over weeks to months, depending on the materials and conditions, the compost heap will reduce in size and gradually transform. When it achieves a dark, crumbly texture and exudes an earthy aroma, it’s ready to be harvested. Use this rich compost to fortify your greenhouse soil, ensuring your plants thrive.

Integrating composting into a greenhouse requires a tad more attention than conventional methods due to the enclosed space, but with these detailed steps, the process can be seamless and abundantly rewarding.

Tips for Successful Greenhouse Composting

Achieving high-quality compost in a greenhouse environment can be incredibly rewarding, but there are certain nuances that can make the difference between mediocre and excellent compost. Here are some detailed tips to help you attain composting success within the confines of your greenhouse:

  • Chop or Shred Materials: Decomposition thrives when materials are more accessible to the microbes responsible for breaking them down. By shredding leaves, chopping up kitchen scraps, or breaking down larger organic waste into smaller pieces, you expedite the decomposition process, making nutrients available faster.
  • Beware of Contaminants: The closed environment of a greenhouse can magnify the effects of diseased plants or pesticide-laden materials. Ensure that you only compost healthy plant waste and avoid any materials that have been treated with non-organic pesticides or herbicides. These contaminants can hinder microbial activity and potentially harm your plants.
  • Embrace Compost Boosters: While not always necessary, compost starters or activators can provide a beneficial kickstart to your compost pile, especially if you’re just beginning. These boosters introduce a robust microbial community to your compost, ensuring rapid and efficient decomposition from the get-go.
  • Smell as an Indicator: Always be attentive to the smell emanating from your compost. A well-balanced compost pile should give off a sweet, earthy aroma. If you notice a foul or putrid odor, it could be indicative of an imbalance, such as too much moisture or a lack of aeration. Regularly turning and adjusting the green-to-brown ratio can usually rectify these issues.
  • Consider Ventilation: Given that greenhouses are enclosed spaces, adequate ventilation is crucial to maintain the right balance of gases for decomposition. Ensure that your greenhouse has vents or openings that can be adjusted based on the compost’s requirements. Oxygen is a friend to compost, while anaerobic conditions can lead to undesirable smells and slower decomposition.
  • Regularly Monitor and Adjust: Like all living processes, composting is dynamic. It’s essential to frequently check the moisture, aeration, and overall health of your compost pile. Based on these observations, adjust the inputs, turning frequency, and moisture levels accordingly.

By heeding these tips and closely monitoring the composting process, you can optimize the decomposition in your greenhouse, resulting in a rich, nourishing compost ideal for promoting vibrant plant growth.

The Synergy of Compost and Greenhouse Plants

The relationship between compost and plants housed within a greenhouse is nothing short of symbiotic. The controlled environment of a greenhouse, combined with the nutrient-dense properties of compost, crafts an ecosystem where plants not only grow but truly flourish. Here’s an in-depth look at the synergy between these two and its resulting benefits:

  • Soil Enrichment: At the heart of every thriving plant is good soil. Compost significantly improves soil structure. By incorporating compost into the greenhouse soil, it becomes more porous, enhancing its drainage capability and preventing waterlogging. Simultaneously, this improved structure increases water retention, ensuring plants have access to moisture for extended periods.
  • Nutrient Replenishment: Compost acts as a slow-release capsule of essential nutrients. As the organic materials in compost break down, they release nitrogen, phosphorus, potassium, and a plethora of trace elements that are crucial for plant growth. For plants in a greenhouse, this means a consistent and prolonged supply of nutrients, reducing the need for synthetic fertilizers.
  • Strengthening Plant Immunity: A less obvious, yet equally important benefit of compost is its ability to boost plant defenses. Compost introduces a multitude of beneficial microorganisms to the soil. These microbes often outcompete or neutralize harmful pathogens, thereby reducing the likelihood of soil-borne diseases. In the protective environment of a greenhouse, this means fewer outbreaks and healthier plants.
  • Stimulating Root Growth: The loose and aerated nature of compost-enriched soil provides an ideal medium for root expansion. With fewer obstructions and a constant supply of nutrients, plant roots can grow deeper and spread wider, anchoring the plant and accessing nutrients from a larger volume of soil.
  • Promotion of Beneficial Organisms: A greenhouse rich in compost is a haven for beneficial organisms like earthworms, predatory insects, and friendly microbes. These creatures play a pivotal role in maintaining a balanced ecosystem, aiding in decomposition, improving soil aeration, and keeping potential pests in check.
  • Buffering Soil pH: Compost generally has a neutralizing effect on soil pH. For greenhouses, where monitoring and maintaining optimal conditions is crucial, adding compost can help buffer the soil, ensuring it remains at a pH conducive to nutrient absorption by plants.

The merger of composting with greenhouse gardening is akin to crafting a meticulously curated nutrient cycle. The waste becomes food, and in this closed loop, plants receive exactly what they need to thrive. This synergy not only ensures optimal growth but also aligns with principles of sustainability and eco-conscious gardening.

Potential Challenges and Solutions

While the amalgamation of composting within a greenhouse offers myriad benefits, it’s not without its challenges. However, with a proactive approach, most of these challenges can be surmounted. Let’s explore some common issues and their remedies:

  1. Odor Issues:
    • Challenge: Decomposition in a confined space can sometimes result in unpleasant odors, especially if the composting process goes awry.
    • Solution: Regular turning of the compost to introduce air can alleviate this. Ensure a balanced carbon-to-nitrogen ratio, and if the compost becomes too wet, add more brown materials. Additionally, maintain good ventilation in the greenhouse to dissipate any build-up of odorous gases.
  2. Pest Attraction:
    • Challenge: The decomposing organic material can attract pests like flies, rodents, or even larger critters.
    • Solution: Utilize a compost bin with a secure lid or cover your compost heap with a thick layer of soil or brown material. Regular turning and maintaining the right moisture level can also deter pests.
  3. Temperature Fluctuations:
    • Challenge: Greenhouses are designed to trap heat, but the decomposition process also generates heat, which can sometimes lead to excessive temperatures detrimental to plant growth.
    • Solution: Regularly monitor the temperature inside the greenhouse using a thermometer. Ventilate the greenhouse during warmer periods and consider using shade cloths to prevent overheating.
  4. Space Limitations:
    • Challenge: In smaller greenhouses, dedicating space for composting can limit the area available for plants.
    • Solution: Opt for vertical composting systems or compact compost bins that utilize space efficiently. Alternatively, practice rotational composting where you start a new compost pile only after the previous one is utilized.
  5. Uneven Decomposition:
    • Challenge: Inconsistent moisture or aeration can lead to patches of undecomposed materials.
    • Solution: Regular turning and maintenance, coupled with ensuring a good mix of green and brown materials, can promote even decomposition. If certain materials persistently fail to break down, consider removing or shredding them for faster results.
  6. Potential for Disease:
    • Challenge: If diseased plant materials are added to the compost, there’s a risk of those diseases persisting and affecting healthy plants.
    • Solution: Always avoid composting diseased plant materials. Additionally, ensure the compost reaches high enough temperatures (between 131°F and 170°F or 55°C to 77°C) as this can help kill off many pathogens.

Navigating the complexities of greenhouse composting requires keen observation and adaptability. However, by recognizing potential challenges and being equipped with solutions, gardeners can foster an environment where both composting and plant growth harmoniously coexist, yielding bountiful rewards.


The dance between composting and greenhouse cultivation is an art as much as it is a science. Together, they create a closed loop of sustainable growth, where waste is transformed into a resource and where plants are nourished in a controlled, optimized environment.

Composting within a greenhouse does not merely involve decomposing organic matter; it is a testament to nature’s ingenuity and resilience. The end product, a rich, black gold, is emblematic of life’s cycle, emphasizing rebirth, regeneration, and growth. Beyond its obvious benefits like improved soil structure and nutrient provision, composting in a greenhouse context epitomizes eco-conscious gardening. It speaks to our deeper responsibility as stewards of the earth, underscoring the importance of waste reduction, resource maximization, and sustainable practices.

However, as we have delved into, this endeavor is not without its challenges. The potential pitfalls, ranging from odors to space constraints, serve as reminders that attentive care, observation, and adaptability are crucial. By addressing these challenges head-on and leveraging the unique advantages offered by a greenhouse setting, gardeners can redefine their relationship with the land, plants, and the environment.

In essence, merging the worlds of composting and greenhouse cultivation paints a vision of the future of gardening – one that is rooted in respect for nature, driven by innovation, and passionate about fostering life in all its myriad forms. It’s not just about plants and produce; it’s a philosophy, a way of life, and a journey towards a greener, more harmonious world.

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