There is nothing better than the aroma of hot coffee in the morning. What’s more, if you are keen on organic gardening, used coffee grounds can benefit your plants too.
If you’re wondering what to do with them, below are some common uses for coffee grounds in the garden.
1. Add to Compost
Compost should have an equal amount of green and brown organic material . Although the grounds appear brown, they are classed as green material. This is because they contain nitrogen.
Add in used coffee grounds with other green material like grass clippings. However, you should also put in brown items like newspapers and dead leaves.
To compost coffee grounds, throw them in your compost bin and mix them in well. And as mentioned, be sure to balance it with some brown compost material. A good measurement is to put in one-third of coffee grounds with the same amount of grass clipping and dried leaves.
Coffee filters can go in the compost too and it might be an idea to ask the local coffee shop/café for any leftover grounds. Coffee grounds will enrich the compost and also help reduce greenhouse gas emissions of the pile.
2. Fertilize with Coffee Grounds
Coffee grounds are good for some plants and the garden, in that, you can use them to fertilize the soil.
To use coffee grounds as fertilizer, sprinkle it on the soil around plant roots and mix it in well.
Alternatively, make tea by adding two cups of used coffee grounds to a gallon of water. Next, leave it to steep in the water overnight. Use the solution directly or as a foliar feed sprayed on leaves and stems.
3. Keep Away Slugs and Snails
Coffee grounds make a great natural pesticide for slugs and snails as it kills them. However, it is not the texture that kills them, but rather the caffeine in it.
To use coffee as a slug repellent, make a caffeine spray of freshly brewed coffee and spray it directly on them. Also, use this homemade slug repellent on and around your plants.
4. Cat Repellent
It is said that coffee grounds make an excellent cat repellent. Cats dislike the smell of it. Therefore, sprinkling some in the areas they tend to use as litter trays may deter them.
Additionally, some gardeners find that adding lemon or orange peel to the mix works wonders. This is because cats hate the smell of citrus fruits.
Rabbits and squirrels are also thought to be repelled by coffee so this method is worth a try to protect your lettuces and other garden veggies.
5. Grow Mushrooms
Another way to use coffee grounds for gardening is to grow mushrooms. Growing mushrooms is a tricky but rewarding process. Ordinary soil requires an underlying layer – a substrate – and grounds are ideal for this purpose.
Coffee grounds are rich in nitrogen, plus other nutrients like potassium, magnesium, iron, and phosphorus . Moreover, they have been sterilized naturally in the brewing process. This is the process:
- Mix the grounds with a bit of boiled straw or sawdust and combine with mushroom spores. Your local gardening store should be able to help with these requirements. However, the precise ratio is 70% coffee grounds, 20% sawdust or boiled/strained straw, and 10% mushroom spore. Also, moisten the grounds a little with a spray bottle before using.
- Disinfect everything involved in the process with rubbing alcohol to prevent bacteria from forming and spreading. Next, mix freshly brewed coffee grounds with the other ingredients (use gloves) and then place in clear food storage bags or large freezer bags. Fill to about 2/3 full, seal with a twist tie (or use a bucket with a clear organic wrap), and poke some air holes in the containers.
- Keep in a dark, preferably evenly humid, area and keep moist. When the fluffy white substance called mycelium starts to develop (2-4 weeks) from the spores, move to a lighter, partially sunny place. Spray with water twice daily.
- Afterward, you’ll start to see small pinheads of mushrooms begin to appear. Enlarge the air holes and when the heads start to flatten out and turn upwards, the mushrooms are about ready to harvest.
Oyster and shiitake mushrooms respond particularly well to this method.
6. Add to Your Worm Bin
Unlike cats, slugs and snails, worms just love coffee grounds.
They need some gritty food to help with digestion. As a result, grounds in the vermicomposting bin are a great addition to help them thrive.
Add coffee grounds to your worm bin, doing so in moderation, being careful not to let it get too acidic. However, if that should happen, you can always add some crushed eggshells to reduce acidity.
Moreover, you will also attract earthworms to the soil when the compost is added.
7. Use as a Mulch
A popular use of coffee grounds is incorporating them directly in the vegetable garden or flower bed as mulch. Spread around the base of plants, they provide a nutrient-rich mulch.
Even so, it is best to add the grounds to other organic materials or compost to avoid clumping. Used coffee ground mulch can be particularly beneficial to acid-loving plants like the azalea family, roses, lilies, and also some root veggies like carrots.
However, avoid using it on tomatoes and young seedlings as the caffeine content will be too high. Brewed grounds are unlikely to affect acid levels as they have a near-neutral pH.
8. Repel Ants
Coffee grounds repel ants rather than kill them. These common insects do not like the scent and acidity of the grounds.
Therefore, sprinkling some of it where the ants are and in your doorways will keep them away.
Plants That Like Coffee Grounds
Fruits and vegetables that benefit from coffee grounds include blueberries, carrots, strawberry plants, cabbage, and radishes.
Additionally, using fresh (unbrewed) coffee grounds benefits acid-loving plants. It can be a boon in growing much-loved flowers and Shrubs like roses, lilies, azaleas, rhododendrons, and hydrangeas.
Furthermore, houseplants and potted plants also benefit from the grounds when used as compost, mulch, pesticide, or fertilizer.
As you can see, there are many benefits of coffee grounds in the garden. Tons get wasted every week but how much better if they can be used in these ways to benefit plants.