Citrus, including peels, rinds, seeds, and pulp from oranges, lemons, and grapefruits, is entirely compostable and can be a beneficial addition to your system. While old gardening advice sometimes cautioned against it, a well-maintained and active compost pile can easily handle citrus waste. Like any other organic material, success depends on proper preparation and balancing the overall mixture to ensure efficient decomposition.
Understanding the Concerns About Citrus Waste
The reluctance to add citrus to compost often stems from two primary issues: acidity and pest attraction. Fresh citrus fruits are acidic, and some worry that adding them will lower the pH. However, this acidity is temporary; as the citrus breaks down, the organic acids are quickly buffered and neutralized by the vast quantity of other materials, especially carbon-rich “browns,” in a balanced pile. Unless a composter is adding extremely large volumes of citrus and nothing else, the impact on the final, neutral pH of the finished compost is minimal.
The high sugar content and strong, volatile aromatic oils in citrus can attract unwanted visitors like fruit flies, ants, and, in some cases, rodents. Proper burial of the citrus within the pile is necessary because pests are drawn to exposed food waste. The waxy, tough nature of the citrus rind itself also slows decomposition, making the material available to pests for a longer time if not managed correctly.
Preparation Methods for Integrating Citrus
Citrus rinds contain adipose cells with essential oils that make them highly resistant to microbial breakdown when left whole. To overcome this, the rinds, peels, and seeds should be chopped, shredded, or torn into small pieces, ideally no larger than one square inch, to maximize the surface area available to the decomposing microbes.
The citrus must be thoroughly mixed into the pile, ensuring it is fully buried deep beneath the surface layers. Surrounding the citrus with material like dried leaves or shredded paper—the carbon-rich “browns”—helps absorb any excess moisture and odor, significantly reducing the chance of attracting pests. The strong citrus scent, which is concentrated in the oils of the rind, will quickly dissipate when buried and mixed into the mass of the pile.
Citrus waste contributes moisture to the pile if too much is added at once. To maintain the ideal moisture level and carbon-to-nitrogen ratio, add a corresponding amount of dry, absorbent brown material every time citrus or other kitchen scraps are introduced. Adding materials like wood chips, sawdust, or shredded cardboard will keep the composting environment aerobic and efficient, allowing the microbes to work quickly.
Managing Citrus in High-Volume Piles
For individuals who generate extremely high volumes of citrus waste, such as those with juicing operations or multiple backyard citrus trees, managing the material in a standard home bin can be challenging. In these scenarios, a high-heat, professionally managed composting system is ideal, as the sustained high temperatures and frequent turning break down citrus rinds rapidly and completely.
When a large volume of citrus exceeds the capacity of a typical home aerobic pile, anaerobic fermentation methods, such as Bokashi, are particularly well-suited for citrus and other acidic foods. Bokashi uses specialized microbes to ferment the waste in an airtight environment, which easily breaks down the tough rinds and essential oils that might slow a traditional aerobic pile. The fermented product, which is highly acidic, is then buried directly in the garden soil to complete its breakdown, providing a safe and effective way to process excess citrus without compromising the main compost system.