The topic of using coffee grounds in the garden is divisive among gardeners. Some home growers swear by reusing grounds in their garden, while others advise against it. This article covers how to use coffee grounds in the garden and what to keep in mind before you begin applying coffee grounds to your garden beds.
Those in favor of using coffee grounds in their vegetable garden state that used and fresh coffee grounds’ ability to improve the pH of their soil. Coffee grounds contain various nutrients essential to plant growth, such as nitrogen, potassium, and phosphorus.
These nutrients, along with some micronutrients, make using spent coffee grounds in the garden an ingenious way to recycle and improve your garden’s soil. This article covers different ways to use spent coffee grounds in the garden and precautions to keep in mind.
- Using Coffee Grounds for Gardening
- How to Use Coffee Grounds in the Garden for Weed Control
Using Coffee Grounds for Gardening
Although using coffee grounds seems like the perfect treat for acid loving plants in your garden, there is more to using leftover coffee grounds than dumping them in the vegetable garden.
Because coffee grounds come from a natural source and are biodegradable, they are beneficial for your plants. However, how you use them and the amount you use is crucial to ensure you don’t cause unwanted harm.
Coffee Grounds as Mulch?
Mulch is an excellent addition to the garden. Adding mulch around your plants helps retain soil moisture by blocking sunlight on the ground. Shielding the ground from sunlight also prevents weeds from growing and competing for nutrients with your other plants.
Because organic mulch is pricey, many home gardeners use coffee grounds for garden soil mulch. The problem with using coffee grounds by themself as mulch is that it may stunt the growth of seedlings if you apply a thick layer. The caffeine in unused coffee grounds also harms young plants.
To avoid these issues, combine coffee grounds with organic matter like compost or leaves to create mulch that benefits your garden better. Mixing materials makes a mulch with varying particle sizes that promotes good soil structure without harming your plants.
Using Coffee Grounds in the Vegetable Garden as Fertilizer
Although coffee grounds possess various nutrients, the main benefit of using coffee grounds for gardening or adding coffee grounds for lawn care application is the release of nitrogen. To boost the nitrogen levels in your garden, sprinkle coffee grounds over your garden soil and thoroughly mix it with the top layer of soil or organic matter.
One concern when using coffee grounds is that it makes the soil too acidic, which can affect the growth of plants that don’t enjoy acidic soil. While coffee is acidic, used grounds are not acidic enough to alter the pH of your soil.
When applying coffee grounds to your garden, use a thin layer and avoid putting too much in the same area. Clumping coffee grounds in the same spot creates a water-resistant barrier that affects the soil’s ability to drain water.
How to Start Composting Coffee Grounds
When it comes to composting, it breaks down into two colors: green and brown. Brown compost materials include dried leaves, pine needles, wood chips, and twigs. Green compost materials include grass clippings, coffee grounds, and fruit scraps.
Consider adding leftover grounds and used coffee filters for green material in your compost bin. Managing your compost pile is crucial for the survival of the bacteria inside the compost and any worms you have in a worm bin. Maintain your compost by keeping a four-to-one ratio of brown to green organic material.
Coffee Grounds as a Pesticide?
If you’re growing plants susceptible to visits from slugs and snails, using coffee grounds in the vegetable garden is a simple way to deter these pests. Although the rough texture of coffee grounds feels minor to humans, soft-bodied pests like slugs hate the abrasive texture of grounds.
Add a layer of coffee grounds around your plants or the entire garden to protect it from slugs. The smell of coffee is a scent cats dislike, so using coffee grounds in your garden is one way to keep your cats or strays from trampling through your garden and using the bathroom.
Since mosquitoes don’t like the smell either, try using coffee grounds for mosquito control while you’re outside on the porch or patio. Add the grounds to a metal container and carefully burn them to repel bugs.
Amend Your Soil pH with Coffee Grounds
Although used coffee grounds have a mostly neutral pH, fresh ground coffee contains more acid. If you find old grounds in the kitchen, using them in the garden is one way to avoid throwing them away.
One caution with using unwashed coffee grounds is that they still contain high caffeine content. Caffeine is not beneficial to all plants, unlike the acid in coffee grounds. Studies show that caffeine may even stunt plant growth if you use it around seedlings and young plants.
Making Liquid Fertilizer with Coffee Grounds
Another method for fertilizing your garden with coffee grounds is to create a nitrogen fertilizer tea. To make enough liquid fertilizer to treat your garden plants, save a few days of old coffee grounds or request grounds from a local coffee shop.
To make your own fertilizer for vegetables and other plants, line a bucket with an old pillow case before filling the bucket with water and adding your spent grounds to the bucket. Leave your bucket of tea to steep overnight and remove the pillowcase the following day.
Squeeze the pillowcase to get all the moisture out of the grounds. Use this tea fertilizer in a watering can and apply it to the foliage of your plants, or use the tea directly in the garden as a nitrogen soak.
What Plants Benefit from Coffee Grounds
Because coffee grounds act as a slow-release nitrogen fertilizer, you can use coffee grounds for gardening with any plant. However, the caffeine and acid of unwashed grounds mean that not every plant handles coffee grounds well.
Fruit trees and bushes are among the best plants to use coffee grounds with because they enjoy acidic soil. Carrots are also plants that like used coffee grounds in the soil around them.
Flowers like hydrangeas and azaleas enjoy the acid and nitrogen released by fresh coffee grounds; however, tomato plants do not. To use coffee grounds around tomato plants, wash your grounds or use grounds leftover from your morning coffee.
Crops like broccoli, leeks, and sunflowers do not do well when treated with coffee grounds. This poor growth is due to natural chemical compounds that coffee grounds release in the soil when used in the garden.
How to Use Coffee Grounds in the Garden for Weed Control
Because the caffeine in coffee grounds has some effectiveness at stunting plant growth, some gardeners use coffee grounds to kill weeds. Rather than pulling the weeds from your garden, try sprinkling coffee grounds over them and raking them into the soil.
Another method for killing weeds involves making a more aggressive form of coffee tea. Boil your coffee grounds and allow the water to cool before spraying or soaking the area to kill weeds.
Because there is much debate about the effectiveness of coffee grounds in the garden, testing is the best way to determine if coffee grounds work for you. Try to grow plants treated with and without coffee grounds to determine the best organic gardening solutions.
If you learned how to use coffee grounds in the garden from our guide, please share our tips on using coffee grounds in the vegetable garden with your fellow home gardeners on Facebook and Pinterest.