Cherry pits are a form of organic matter that can be integrated into a compost pile. While they are technically compostable, simply tossing them into a bin will not yield quick results. These pits require specific preparation to break down efficiently. Their natural durability means a gardener must actively manage them to avoid issues with decomposition speed, chemical concerns, and unwanted germination.
Preparing Pits for Efficient Breakdown
Cherry pits are classified as a “brown” material in composting, meaning they are a source of carbon, but their physical structure presents a significant challenge to decomposition. The outer shell, known as the endocarp, is extremely hard and consists of a high percentage of lignin, a complex polymer resistant to microbial action. This lignin content can range from 30% to 45%, making the shell similar to hardwood in its resistance to decay.
If added whole, cherry pits may take years to fully decompose because microbes and heat cannot penetrate the dense casing. The breakdown process relies on microorganisms accessing the internal starches and cellulose, which the lignin shell prevents. To overcome this natural defense, the pits must be physically reduced in size before being added to the compost heap.
Crushing, grinding, or cracking the pits exposes the interior surface area to the heat and microbial community of the compost pile. This mechanical action drastically reduces the decomposition time from multiple years to mere months. A hammer, food processor, or dedicated grinder can be used to break the shells, which then allows the pits to function as an effective carbon-rich component.
Addressing the Cyanide Concern
A common concern regarding cherry pits is the presence of toxic compounds within the kernel. Cherry pits, along with those from other stone fruits, contain a cyanogenic glycoside called amygdalin. When the pit is crushed or digested, this compound can be hydrolyzed to release small amounts of hydrogen cyanide (HCN).
While amygdalin is toxic if consumed directly in high quantities, the composting process effectively manages and neutralizes this risk. The high temperatures achieved during the thermophilic phase of hot composting (typically above 130°F) accelerate the degradation of the amygdalin. Simultaneously, active microbial populations within the pile break down the complex organic molecules, including the cyanide compounds.
The resulting finished compost is safe to use in vegetable gardens and other planting areas. The minimal initial concentration of amygdalin is rapidly metabolized by the composting environment, ensuring no harmful levels of cyanide remain to contaminate the soil. Incorporating prepared cherry pits is a safe practice for creating a rich soil amendment.
Preventing Sprouting in the Compost Pile
Cherry pits are designed to sprout, and if they survive the composting process, they may germinate in the finished compost or garden beds. The seeds require a period of cold, moist conditions, known as stratification, to break dormancy. If the compost pile remains too cool, this stratification process can occur naturally.
To prevent unwanted cherry seedlings, the pits must be exposed to high heat to destroy their viability. Maintaining a true hot compost pile is the most reliable method, requiring the internal temperature to reach at least 131°F (55°C) for several days. Proper turning of the pile is necessary to ensure the pits are cycled through the hottest core area, guaranteeing heat exposure.
Alternatively, pre-treating the pits before crushing can eliminate the risk of sprouting. Soaking the pits in boiling water for several minutes or subjecting them to prolonged freezing before they are crushed destroys the embryo’s viability. Even with pre-treatment, a gardener should be prepared to pull any occasional cherry sprouts that might emerge, as some pits can be resilient.