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
The compost should have an equal amount of green and brown organic material . Although coffee 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 leftovers. Coffee grounds will enrich the compost with nitrogen.
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 leave it there.
Alternatively, make tea by adding two cups of used coffee grounds to five gallons of water. Leave it to steep in the water overnight. Finally, use the solution as a liquid fertilizer for your plants.
3. Keep Away Slugs and Snails
Coffee grounds make a great natural repellent for slugs and snails because of the abrasive texture and unpleasant smell. However, a caffeine solution with 1-2% caffeine works better as it will kill them.
To use coffee grounds as a slug repellent, sprinkle some on the soil around your plants. You can also make a caffeine spray of freshly brewed coffee and spray it directly on the pests.
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 coffee 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.
- Mix freshly brewed grounds with a bit of pasteurized straw and combine with your mushroom spawns. Your local gardening store should be able to help with these requirements. However, the precise ratio is 70% coffee grounds, 20% boiled/strained straw, and 10% mushroom spawn.
- 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, and poke some air holes in the bag.
- 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.
- You’ll then 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 mushrooms 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. So, coffee grounds in the vermicomposting bin are a great addition to helping earthworms 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 moderate soil 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 into 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 azalea, gardenia, rhododendron, and also some root veggies like carrots.
However, avoid using it on plants that do not like acidic soil.
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
Fruit trees and vegetables that benefit from coffee grounds include blueberries, carrots, elderberries, peppers, tomatoes, sweet potatoes, and radishes.
Additionally, fresh (unbrewed) coffee grounds benefit other acid-loving plants greatly. It can be a boon in growing much-loved flowers and shrubs like zinnias, camelia, azaleas, rhododendrons, and hydrangeas.
Furthermore, some houseplants and potted plants also benefit from it 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.