However, tomatoes do not like fresh coffee grounds; keep them out of that area of the garden. (As in the classic twenty-foot high tomato plant that produces two tomatoes.) While used coffee grounds are only slightly acidic, fresh (unbrewed) coffee grounds have more acid. Many gardeners have had similar success, even though the jury is still out on whether or not used coffee grounds are a magic bullet in the garden. If used with care and common sense, they are a worthwhile addition your compost heap and your soil. Coffee grounds added to compost and used in the garden as organic fertilizer give your tomato (Solanum lycopersicum) plants a boost, attract earthworms and … Thanks for this site, Amber Tomato Dirt responds: Glad to hear coffee grounds are working for your tomato plants! Whether you are composting with coffee grounds or using used coffee grounds around the yard, you will find that coffee can give your garden as much of a pick me up as it does for you. Have you used coffee grounds in the garden? Coffee grounds are free organic matter, whether a by-product of your at-home daily brew or collected from coffee shops that are only too glad to give them away for nothing. What was your experience? But coffee grounds have few potential negatives in a compost pile, where they are a great high-nitrogen component for mixing with shredded fall leaves. Using coffee grounds to grow healthy tomatoes is a smart idea for several reasons. Your acid-loving plants like hydrangeas, rhododendrons, azaleas, lily of the valley, blueberries, carrots, and radishes can get a boost from fresh grounds. Coffee grounds and gardening go together naturally.