Can You Compost Rhubarb Leaves? Yes, And We Know How

  • By: Sam Richards
  • Date: July 16, 2023
  • Time to read: 8 min.

Composting is an eco-friendly practice that has gained popularity in recent years, both among avid gardeners and environmentally conscious households. This method of waste management is an excellent way to recycle organic matter, transforming it into a rich, fertile supplement that enhances the health and growth of plants.

One of the intriguing aspects of composting is its ability to break down a wide range of materials. From kitchen scraps to yard waste, most organic materials can be composted. However, certain items often cause confusion regarding their compostability due to inherent characteristics. One such item is the rhubarb leaf.

Rhubarb, a plant well-known for its edible stalks, also produces large green leaves that are typically discarded because of their oxalic acid content, which can be harmful when ingested. This raises an important question: can these leaves, despite their toxicity, be safely composted and used to enrich our gardens?

In this article, we delve deeper into the nature of rhubarb leaves, the concern surrounding their toxicity, and the process by which they can be safely composted. We aim to provide clear, factual information to address these concerns and guide those interested in maximizing their composting efforts.

Understanding Rhubarb

Rhubarb is a perennial plant known for its characteristic long, red stalks and large, green leaves. Often considered a fruit, despite technically being a vegetable, rhubarb is a favourite ingredient in a variety of culinary dishes, particularly desserts. Its stalks, once cooked, provide a unique combination of tartness and sweetness, making them perfect for pies, compotes, and jams.

Despite the stalks’ popularity, the leaves of the rhubarb plant are usually discarded. Unlike the edible stalks, rhubarb leaves contain a naturally occurring compound known as oxalic acid. This compound is what gives the leaves their somewhat shiny appearance. It also contributes to their toxicity when ingested, as oxalic acid can interfere with the body’s ability to metabolize certain minerals, causing discomfort and potentially leading to more serious health issues.

Given this context, many gardeners and homeowners face a conundrum. Rhubarb plants, especially when well-tended, can produce a large number of leaves throughout their growing season. Disposing of these leaves can seem wasteful, particularly for those who aim to maintain sustainable gardening practices. Consequently, the question arises: can these leaves, in all their abundance and despite their potential toxicity, be used beneficially in a compost heap? This article aims to address this question, exploring the feasibility and safety of composting rhubarb leaves.

Are Rhubarb Leaves Poisonous?

Rhubarb leaves contain oxalic acid, a natural compound that, in large amounts, can cause discomfort and health problems in humans. This is why it’s generally advised not to eat these leaves. However, it’s important to understand that the toxicity of oxalic acid decreases significantly during the composting process, a crucial fact that allows us to safely compost rhubarb leaves.

Composting Rhubarb Leaves Safely

Despite their inherent toxicity, composting rhubarb leaves is a safe and beneficial practice, thanks to the biological and chemical processes that take place within a compost pile. During composting, various microorganisms break down organic matter, and in the process, neutralize potentially harmful compounds, including oxalic acid.

Composting rhubarb leaves is a relatively straightforward process, but it requires attention to detail to ensure safety and effectiveness. Follow these steps:

  1. Prepare the Rhubarb Leaves: Before composting, cut or tear the leaves into smaller pieces. This increases the surface area available for microbes to work on and expedites the decomposition process.
  2. Add to Compost Pile or Bin: Place the prepared rhubarb leaves in your compost pile or bin. The location of your compost setup should ideally be in an outdoor area that’s accessible yet out of reach from children and pets.
  3. Balance with Brown Material: Rhubarb leaves are classified as green compost material (high in nitrogen). To maintain a balanced compost pile, you should add an equal amount of brown material (high in carbon) such as dried leaves, straw, or paper. This balance aids the composting process and helps neutralize the acidity of rhubarb leaves.
  4. Turn the Compost Regularly: Regular turning of the compost pile ensures even decomposition, promotes aeration and facilitates the breakdown of oxalic acid. Aim to turn your compost pile every week or two.
  5. Monitor the Compost Process: Keep an eye on the compost pile’s progress. The leaves should decompose entirely within a few weeks to months, depending on your local climate and the balance of your compost pile.
  6. Use the Finished Compost: Once the composting process is complete, and the rhubarb leaves have fully decomposed, you can use the nutrient-rich compost in your garden. It will enhance soil fertility and promote healthier plant growth.

Remember, while composting rhubarb leaves is safe, it’s important not to overdo it. Balance is key in composting. Too many rhubarb leaves, like any other single type of green material, can unbalance the compost and slow down the composting process. Therefore, incorporate a diverse range of green and brown materials for the best results.

Other Considerations for Composting Rhubarb Leaves

While the composting of rhubarb leaves is generally a safe practice, it’s important to consider several factors to ensure the optimal performance of your compost heap and to safeguard the health of those around you.

  1. Diversify Your Compost Material: Rhubarb leaves should not make up the majority of your compost heap. Balance is a crucial element of composting, so it’s essential to include a diverse range of green and brown materials. This diversity fosters an environment that supports a healthy microbial ecosystem, necessary for effective decomposition and composting.
  2. Safe Handling: Even though composting neutralizes the oxalic acid in rhubarb leaves, you should still handle these leaves with care. It’s a good idea to use gloves when handling large quantities of rhubarb leaves to prevent any potential skin irritation.
  3. Children and Pets: Although the composting process breaks down the oxalic acid in rhubarb leaves, it’s prudent to keep the compost heap away from children and pets while the decomposition is ongoing. This is because the leaves may still contain some oxalic acid during decomposition, which could be harmful if ingested in large quantities.
  4. Monitor Your Compost Heap: Keep an eye on your compost pile’s progress. Ensure it maintains a good balance of materials, stays moist but not wet, and is turned regularly to speed up decomposition and evenly distribute heat and microbial activity.
  5. Don’t Rush the Process: The decomposition process needs time. Be patient and give the compost heap sufficient time to fully break down the rhubarb leaves and other materials. The resulting compost should be dark, crumbly, and earthy-smelling, indicating that it’s ready to use in your garden.

By considering these factors, you can safely and effectively compost rhubarb leaves while maximizing the benefits for your garden.

Benefits of Composting Rhubarb Leaves

The practice of composting rhubarb leaves, when done correctly, offers numerous benefits for your garden, the environment, and your overall waste management strategy. Here are several key benefits of incorporating rhubarb leaves into your composting routine:

  1. Nutrient-Rich Compost: Rhubarb leaves contribute to the nutrient profile of your compost pile. As these leaves break down, they release nitrogen, an essential nutrient that helps plants grow healthily. The end product is a rich compost that can significantly boost the fertility of your garden soil.
  2. Waste Reduction: Composting rhubarb leaves aids in reducing waste. Instead of discarding rhubarb leaves as waste, you can transform them into a valuable resource. This approach aligns with sustainable living practices and contributes to the reduction of organic waste in landfills.
  3. Improving Soil Structure: Compost made from rhubarb leaves, along with other compost materials, helps to improve the physical structure of the soil. It enhances the soil’s ability to retain moisture and nutrients, promotes aeration, and fosters a healthy habitat for beneficial soil organisms.
  4. Pest and Disease Resistance: Healthy, nutrient-rich soil helps plants become more resistant to pests and diseases. By adding composted rhubarb leaves to your garden, you are essentially boosting your plants’ immunity, reducing the need for synthetic pesticides and fertilizers.
  5. Cost-Efficient Fertilizer: Homemade compost, including that made with rhubarb leaves, is a cost-effective alternative to store-bought fertilizers. It provides a broad spectrum of essential nutrients required by plants, contributing to their robust growth and productivity.

By composting rhubarb leaves, you’re not only taking advantage of a commonly discarded resource but also making a significant contribution to a healthier garden and a more sustainable planet.


Can You Compost Rhubarb Leaves?

Yes, you can compost rhubarb leaves. The composting process breaks down oxalic acid, neutralizing its harmful effects.

What Makes Rhubarb Leaves Dangerous to Eat?

Rhubarb leaves contain oxalic acid. When ingested in large amounts, it can cause health problems.

Will Rhubarb Leaves Harm Microbes in Soil?

No, once fully composted, rhubarb leaves will not harm soil microbes.

Will Rhubarb Leaves Make Compost More Acidic?

The oxalic acid in rhubarb leaves can contribute to acidity, but the effect is minimal and balanced out during the composting process.

Which Plants Will Benefit from Composted Rhubarb Leaves?

Most plants will benefit from composted rhubarb leaves as they add essential nutrients to the soil.

Are Rhubarb Leaves Safe For Pets?

While decomposing, rhubarb leaves may still contain some oxalic acid, which can be harmful to pets if ingested in large amounts. It’s best to keep pets away from the compost pile.


The composting journey is filled with fascinating discoveries, and the revelation that rhubarb leaves can be composted safely is certainly one of them. Despite their oxalic acid content, which deters their consumption, rhubarb leaves can be transformed into a valuable resource through the composting process.

As we’ve seen, the process of composting breaks down the oxalic acid in rhubarb leaves, neutralizing their toxicity and allowing these leaves to contribute to the nutrient richness of our compost heaps. It’s a simple process, yet it requires a measure of care and balance to ensure the effectiveness and safety of your compost pile.

Adding rhubarb leaves to your composting regimen is an excellent way to enrich your garden soil with essential nutrients, promote a healthier and more productive garden, and contribute to the sustainability of our planet. The practice of composting rhubarb leaves embodies the very spirit of composting — taking what’s often seen as waste and transforming it into a resource.

Nonetheless, we must always be cautious and informed when adding new materials to our compost heaps. Balance in composting is key, and while rhubarb leaves can be composted, they should not be the sole or dominant ingredient in your compost pile. We also need to be mindful of our compost heaps’ locations, especially when children and pets are around.

In conclusion, rhubarb leaves can indeed find a second life in compost heaps, providing benefits not just to our gardens, but to our waste management strategies and our overall impact on the environment. As with any aspect of composting, or gardening in general, knowledge and understanding are our best tools, allowing us to make the most of what nature provides, including rhubarb leaves. Happy composting!

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