Kitchen Scraps and Coffee Grounds for Plants

Easy Composting Doesn’t Need Special Equipment. Let Nature Do Its Work.

Kitchen Scraps and Coffee Grounds for Plants

Composting isn’t always a fine art. Sometimes, it just means saving coffee grounds for plants and dumping them on the soil.

When I started my first garden as an adult, a friend offered to save coffee grounds for plants growing in my soil. She said, “Coffee grounds are steroids for tomatoes.” I didn’t drink coffee and was not aware of benefits such as helping break up hardpan clay and raising soil acidity. The biggest advantage of using coffee grounds for plants is nitrogen release, and gardeners are often advised to add them to compost piles. I now accept all the grounds I’m offered so I can help my garden grow because they’re a high-nitrogen “green.”

“How many greens do I add to what percentage of browns if I want to make a balanced compost?”

Honestly, don’t ask me unless I have Google handy because I’ve learned to do it more by feel and intuition. And one rule I follow: decomposing plant waste is never too “hot” to go on living plants. So I don’t wait until carrot shavings, cornhusks, or spoiled beans compost. Saving coffee grounds for plants can help your garden the day after you enjoy that hot brew.

Fresh plant matter helps growing vegetables because active decomposition creates nitrogen. And nitrogen is what makes plants grow.


Composting definitely has its place. I’ll never claim it doesn’t. Learning how to compost chicken manure can create valuable fertilizer without risking diseases or a nitrogen content which will damage a garden. That high-nitrogen manure is just too much, and allowing it to decompose for a while releases enough that you can use remaining nitrogen for growing vegetables. Composting also breaks down those browns, high-cellulose woody, dead materials like dry leaves, bark, wood chips, and paper bags. Mixing manure with browns builds important soil bulk.

I employ a method of composting in planter boxes, using nothing but recycled materials and homestead waste to build containers of soil where no dirt was before. It’s a lazy, carefree method that involves building a wooden box and throwing in manure, dead leaves, livestock bedding, and kitchen waste. Wondering how to add calcium to soil? Eggshells and whey are great. If I intend to use the box the next spring, all manure and wood chips go on the bottom; the kitchen scraps and bedding lie on top because I know they won’t hurt young plants. Within minutes of adding carrot shavings or my saved-up coffee grounds for plants, I insert vegetable seedlings. Little plants feed on the nitrogen release of those decomposing scraps. By the time mature roots meet manure, it has composted enough to be rich and safe.

I also mix scraps into my in-ground garden at the same time that I seed or transplant. Dig holes and dump plant matter. Cover with soil, making sure there are several inches of dirt between scraps and the seeds. Smooth over. Plant. If the scraps are already in an easy-to-compost form, I know they will soon become soil and won’t interfere with root development.

Easy-to-compost kitchen waste includes vegetable peelings such as carrot shavings and onion peels. Cooked vegetables already have the cellular structure broken down, so they decompose easily. The same goes for frozen vegetables that may have become bitter or freezer-burnt. Thaw or cool vegetables before using near living plants. Any leftover vegan food can be used, but keep a conservative hand with high-fat items such as nuts and avocados. It’s rare that any fatty plant matter, in its unprocessed form, will disturb soil composition; just don’t dump in vegetable oils.


I enjoy sweet corn on the cob in early July, a good six weeks after planting my warm-weather crops. It’s too late to add cornhusks to the dirt so I use them as mulch. Separate leaves and lay husks along the ground, around plant stems, to hold in moisture and protect the soil. After harvest, I push husks into the soil so natural bacteria fungi can start decomposition.

Another good top-dressed kitchen byproduct includes coffee grounds.

“Wait! You can’t use coffee grounds for plants! They’re too high in nitrogen!”

Yeah I know, I hear this every single time someone sees me sprinkle dark, moist grounds around my tomatoes. I have never managed to sprinkle so many coffee grounds for plants that my garden is negatively affected. This is because, unlike with manure, nitrogen won’t release until the grounds begin decomposing, and the release is gradual.

Just don’t plant tomatoes directly into a pot of coffee grounds. Make sure the scraps intersperse with existing soil or lie on top. If you end up with too many coffee grounds, throw those into the compost pile to use next year.

Kitchen Materials That Should Never be Added Directly to Growing Gardens

  • Any meat, bone, or other animal product except hair, eggshells, or whey*.
  • Oils and fats, even if they come from plant sources.
  • Large pieces such as banana peels and citrus rinds.
  • Large pits such as peach stones.
  • Living seeds: any seeds that may sprout and grow where you don’t want them. Save cantaloupe innards for compost bins.
  • Containers such as tea bags, coffee filters, mushroom cartons, and “Green” produce bags. Save these for the compost pile so they can break down.
  • Ashes from coal, charcoal, or treated wood. Don’t even put these in a compost pile.
  • Keep in mind that leftover dinners, even 100% plant-based, are still tasty and may attract animals that can stomp your tender plants. It may also smell sour as it decomposes. I prefer to dig this into the soil before planting or add to compost.

*Exception: Manure from rabbits, goats, sheep, llamas, and alpacas is a cold manure which releases nitrogen slowly as it decomposes. It can be used directly on tender plants, including most seedlings.

Whether using coffee grounds for plants, mulching with discarded corn husks, or exploring soil amendment as one of the many uses for whey, don’t send kitchen scraps to the landfill if they can make your garden better.

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