Most vegetables tend to grow better in soil that falls near a neutral or near-neutral soil pH. Some of your most favorite vegetables and herbs will adapt when growing in acidic soil, however there are some that actually prefer slightly acidic soil.
If you want to amend your soil and slightly improve the acidity for these varieties to thrive, try mixing in a small amount of fresh, (un-used) coffee grounds into the soil around these "acid-loving" plants. (Tomatoes, Marigolds, Dill, Endive, Spinach, Parsnips, Garlic, Parsley, Rutabagas, Turnips, Peppers (HOT) & (Sweet), Carrots, Cauliflower, Cucumbers, and Squash.)
Once you determine whether you want to apply "a little" or "a lot" of acidity via your coffee grounds you're ready to start using this readily available fertilizer in your garden.
TIP: Scroll down to the bottom of this post to read even more ways you can coffee grounds in your garden. For example, you can make a "tea" out of the used grounds to use as a spray to repel insects and caterpillars - naturally!
Most people would assume that used coffee grounds are very acidic, but tests on the pH of this natural fertilizer shows that they are only mildly acidic. These used grounds therefore make a good "side-dressing" to many plants because as they decompose they tend to return to a near neutral pH. This means your plants get an added boost of nutrients right away, and then they will slow down over time making your plants ready to be re-fertilized.
Now fresh, un-brewed coffee grounds are more acidic than their brewed version. Because of this, they can be used slightly different in your garden. If you're growing things that don't mind the extra boost of acidity, then apply new grounds.
⚠️ IMPORTANT: Don’t use coffee grounds that have fermented or rotted. Use fresh organic grounds. Drip grounds tend to work better than boiled grounds, as they are higher in nitrogen content. You can also sprinkle some of the used grounds around flowers and vegetables before watering them for a slow-release of nitrogen. Try buying compostable non bleached coffee filters, as this makes it easy to just throw both grinds and filters into your compost box.
More ways .... to use coffee grounds in your garden:
TIP #2 - Use small amounts to help suppress fungal rot or wilt, such as Fusarium, Pythium, and Sclerotinia species.
TIP #4 - Spread around the base of your azaleas, hydrangeas, roses and lilies.
TIP #5 - Use grounds to suppress weeds in your garden.
To use your coffee grounds as sheet mulch, simply dump them around the base of your plants and rake them out to a fine layer. If you get the layer too thick, you can count on it getting moldy.
TIP #6 - Grounds can also work well as a natural deterrent for animals such as cats and rabbits.
TIP #7 - Use as a Slug deterrent. If slugs are getting the best of your tender young leaves inside of your vegetable garden, try placing some used coffee grounds as a barrier on top of the soil around your plants. The rough grounds will scratch their little bodies making it uncomfortable for them to find their way onto your young and fragile new plants.
Tip #8 - Great for worm bins and composting! Try letting your grounds sit for about 3 days before adding them into your worm bins or compost. The high nitrogen content in coffee grounds make for good worm food, but try to not overdo it. Limit the amount of grounds you add for a successful compost, especially when worms are involved.
