In celebration of sunnier weather, getting outside, and launching an educational section of our website with so much coffee world knowledge to come, we wanted to share information on gardening and composting with your coffee. Whether you’re trying to reduce waste or find some potential solutions to pests, we’re here for all things gardening, and we'll be providing some (free) materials available for pickup - read on for more info!

Used coffee grounds are a popular soil additive as a natural solution to prevent weeds, repel pests, and attract earthworms. While a lot of practices aren’t totally backed by scientific studies, word on the street is that coffee grounds are one of those miracle ingredients to achieving a healthy garden.

Coffee grounds can help create a more nitrogen rich soil, so if you’re growing a lot of food crops like tomatoes, cucumbers, zucchini, or carrots, for example, spent coffee grounds are an option for when you’d prefer to use something you already have rather than purchasing gardening solutions or fertilizers.

When composting coffee grounds, naturally occurring bacteria and fungi break down the grounds, which become attractive to earthworms as a food source. They consume the coffee and transport it as they burrow through the soil, which can help with dispersion, aeration, and agitation. Coffee grounds can also help your soil fight off common fungi, rots, and wilts, so as long as you find a balance, there’s no downside to trying it out.

Be sure to limit the amount of grounds to approximately 20% or less when adding to compost. Over 30% of compost made up of coffee grounds has been found to be detrimental to the overall balance of the compost, and may slow the germination rate of your seeds. Some of you might be worrying about acidity levels - don’t! Used grounds are actually neutral, or very close to it. Additionally, the pH levels of your compost will change over time, so they’re constantly in flux.

If you don’t have the ability to compost, you can start by sprinkling coffee grounds directly on the top soil layer in your garden, or raking the grounds into the soil. Make sure to keep the layer around 1/4 inch, or no more than half an inch. To be safe, avoid using coffee grounds when you’re starting from seed, and just use as an additive once your plants are sprouted, or after planting your starters.

Similarly, coffee chaff, which is the papery outer skin of roasted coffee, can be used in the same way as grounds. Because it’s so light and thin, it can be thought of as a “dry” version of spent grounds. Jute coffee bags will decompose on their own over time, and can be used for lining planter beds or covering soil to kill weeds between harvests. You can also use them as planters themselves by filling them with soil and planting directly in the bags.  For anyone interested, we’re happy to offer chaff and jute bags available for pickup at our HQ Roastery, just place an “order” here and we’ll coordinate with you!