Here's why you should be watering your plants with coffee (2024)

Coffee is good for a lot of things: getting you out of bed in the morning, making it through the dreaded 3 p.m. slump, and, in my case, just plain old surviving. And apparently, that delicious brew is also good for your garden.

According to some horticulture experts, more people should be watering their plants with coffee instead of plain water to help their gardens thrive.

Because we're very intrigued (could this finally be the solution to what to do with what's left in my pot each morning?!), we broke down exactly what coffee does for your plants and how to use it the right—and most effective—way.

How can watering with coffee benefit my garden?

Coffee contains a lot of nitrogen, which not only kills off weeds and bacteria but can also help certain types of plants (a.k.a those that prefer more acidic soil) flourish.

Plus, your daily cuppa also contains significant amounts of magnesium and potassium, both of which are key factors in plant growth and health.

Are there any potentially harmful effects of watering with coffee?

The key is to only use coffee as a substitute for water once a week. Because just like too much coffee is a bad thing for humans (beware the jittery, anxious, over-caffeinated mess I become if I drink more than six cups), it's also a bad things for plants.

"It's fine to use coffee as a fertilizer," our senior lab testing technician, Jonathan Chan, says. "However, you should be careful because coffee can raise the acidity of the soil. Caffeine also is known to have a negative effect on plant growth."

You'll know if you're giving your plants too much coffee if you notice the leaves turning yellow or brown, which is a sign that the soil has become too acidic. At that point, simply dilute your coffee before using it to water your plants.

How else can I use coffee in my garden?

If you're wary of watering with coffee, there are other ways to use your leftover brew in your garden.

Chan's advice is to sprinkle the grounds into the soil or use it for composting.

"The best way to utilize coffee would be to add it a compost," he recommends, adding that it "will dilute the coffee's acidity and allow microorganisms to break down the caffeine."

Bonus: Adding coffee to your garden can also keep away pests and slugs while attracting earthworms (they eat the grounds), which are great for your plants.

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