Did you know that one of the best ways to perk up and provide a little nutrition for your indoor houseplants is with coffee grounds?
It’s true! Coffee grounds are popular for powering vegetable plants, herbs and perennials in the great outdoors. But it just so happens, when used correctly, they can also be a big help to indoor plants as well.
The grounds from brewed beans have a lot more to give than just the rich, tasty coffee they produce. Coffee grounds are teeming with nutrients. In fact, not only do they contain trace amounts of phosphorous, magnesium and potassium, but calcium, zinc, and copper as well.
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In addition, as coffee grounds leach and break down in the soil, they also help to fix nitrogen levels in the soil. Nitrogen that helps to power better root growth – and bigger and brighter blooms. It is certainly easy to see with all of its goodness why coffee helps plants grow better!
But with that said, there are a few key differences when using grounds on indoor plants vs. outdoor perennials, vegetables and flowers. Today, we take a look at those differences, and how to best use spent coffee grounds to power the plants you grow indoors.
How To Use Coffee Grounds On Houseplants
For starters, it is important to realize that simply dumping coffee grounds on the soil surface of any indoor plant is not a good idea. In fact, doing so will most likely cause a plant more harm than good.
Coffee grounds retain a tremendous amount of moisture. Although that might sound like a positive, it can actually be very detrimental to house plants. Coffee grounds are so good at retaining moisture that when placed directly on the soil surface, they over-saturate a plant’s root system.
When this occurs, the roots of the plant swell excessively and become unable to take in nutrients. The end result is a houseplant that turns yellow from a lack of nourishment, and a root system that slowly rots and dies.
So exactly how can you use coffee grounds to help plants and not harm them? There are actually a couple of methods that are both quick and effective – with the easiest of them all being to make a fertilizing “tea” with the spent grounds.
Making & Using Coffee Fertilizing Tea – Using Coffee Grounds On Houseplants
One of the best ways to use coffee grounds to power your houseplants is by making a fertilizing tea from the spent grounds. Much like compost tea, the liquid is quickly absorbed by the plants roots for an energizing boost of nutrients.
So why not just water your plants with regular coffee? Unfortunately, fresh brewed coffee is simply too strong. But by making a much weaker “tea” from the spent grounds, it contains a more useful and safe level of nutrients.
Making a fertilizing tea from coffee is actually a very simple process. The easiest method is to simply run another pot of water through your coffee maker. Keep the grounds from your first batch in place, and re-make an entire pot. Of course, you need to let it cool before using, but the weak solution will supply a gentle source of nutrients to your plants.
Another method for making tea is to simply dump spent grounds into a container and fill with water. Allow it to steep for a few hours and soak in the nutrients. To use, strain to remove the grounds, and you are ready to water!
As a rule of thumb, the weak coffee tea can be used every 7 to 10 days. Any more and you risk over-fertilizing indoor plants with too many nutrients.
Working Grounds Into Potting Soil – Using Coffee Grounds On Houseplants
Another method for using grounds is to mix and blend them in small amounts into your potting soil. Although we covered above why simply dumping large amounts of spent grounds on an indoor plant can be harmful, they can be mixed sparingly into soil to provide beneficial nutrients. (See: How To Save Coffee Grounds In The Winter)
When repotting plants, thoroughly mix in a quarter cup of grounds for every 4 to 6 cups of potting soil. By blending it into the soil, it will release its power slowly. All without the worry of clumping together and holding too much water in place around roots.
For existing plants, work a teaspoon or two (depending on the size of the plant) into the top surface area of the soil. Again, be careful to mix and blend it in well. This keeps the soil from holding too much water in one place.
One note of caution on this method. You will want to avoid this process with cacti and succulents. Both prefer dry soil, and grounds should be avoided in the soil completely. Even with blending, it still will hold too much water and can harm the plants.
Using The Right Coffee – Using Coffee Grounds On Houseplants
It is important to also note that not all coffee grounds are the same. Flavored coffees and coffees with artificial ingredients should not be used on houseplants. Unfortunately, these brews can contain harsh chemicals that can harm plants.
Instead, when using coffee grounds, stick with the grounds from plain coffee. And it doesn’t matter if they are regular or decaffeinated – both varieties are fine. You can also safely use coffee blends made from several different bean types. The key is to avoid coffees with artificial additives.
Last but not least, it is important to note that we are referring to using spent coffee grounds, and not fresh, un-brewed coffee grounds.
Fresh coffee grounds are by nature much more acidic, and can upset the balance of the soil’s PH levels. The process of brewing actually reduces the acidic level in coffee grounds to a fraction of the acid when fresh.
And, whatever you do, don’t throw those grounds out once you have used them for making coffee tea! Even though you have taken some their nutrition out, they are still wonderful for powering up your compost pile. See: How To Compost Like A Pro)
Here is to energizing your houseplants with coffee grounds!
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