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Can You Water Your Plants With Leftover Coffee?

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Can You Water Your Plants With Leftover Coffee

We all must have gone through times when we order or make coffee and end up not finishing it because you lose your appetite or maybe you are so caught up with other things and forgot you had one. And, at this moment, you would feel really guilty about this leftover coffee, the 5 dollars you spent, and wonder what you can do with this leftover drink. 

ith Leftover Coffee? intro

I am sure that each one of us does not want to waste a single drop of that precious coffee in the sink, and there are times when we look up for alternatives such as could use it to make tasty treats, using the coffee to water the plants and add the coffee grounds to compost. But, there are times when we are hesitant, wondering if the plants are going to die. 

If you’ve been in that situation, this article is a perfect start as it will answer whether coffee can be used to water the plants and if so, how to water them rightfully. 


Nutrients in Coffee 

Firstly, it is undeniable that coffee is one of the most consumed beverages among citizens all over the map because of its taste and addictiveness to some people. Unsurprisingly, it also contains a diversity of nutrients that are essential for our overall health, and specifically to this article – to our plants.

Coffee grounds and liquid coffee such as brewed coffee are sources of nitrogen, which is essential to the growth of plants’ stems, making them healthy and green. Moreover, it also accommodates calcium, potassium, magnesium, and iron, which are also crucial to the soil and plants’ growth. 

Coffee Grounds 

Coffee Grounds 

There are diverse types of coffee grounds, but in general, it is the source of nutrients like nitrogen that is needed to better the quality of the soil. Most soil does not contain an adequate amount of nutrients to help the plant grow significantly. Hence, we can use coffee grounds as compost or add them directly to the soil. With the right amount, it can raise the acidity level of the soil because it acts as a fertilizer,  which is significant for plants in need of acidic soil such as blueberries, azaleas, lettuce, etc. 

Other than that, the caffeine content in coffee grounds is also a food source to attract worms which is beneficial for the growth of plants as it provides nutrients, better drainage, and a more stable soil structure. Also, it diminishes the attraction of cats from roaming and ruining your garden. 

Liquid Coffee

Apart from used coffee grounds, a variety of coffee types can be used, for instance, hot or cold brew, even the black coffee you order from a cafe that isn’t finished can also be used for watering your pot of houseplants if done rightfully. 

Liquid Coffee

You may wonder ‘Why rightfully?’, ‘Can’t I just pour it in like water?’. To answer simply, coffee and water are different as coffee contains more acid while water is a neutral compound. And, by rightfully refers to the dependency and characteristics of each plant to coffee. Plants that prefer more acidic soil or plants with low pH levels such as African violets, Phalaenopsis orchids, Roses, would prefer and react fondly to coffee. Other outdoor acid-loving plants such as Azaleas, Rhododendron, or Lupines would react just fine with cold coffee watering periodically. Also, it is efficient to use coffee for dry compost piles as well. 

It is a good and unique idea if you decide to water your plant with a cup of coffee periodically but there are points to keep in check. You need to monitor if the foliage- basically leaves, starts to turn brown, if so then it is a sign that your plant is not fond of the acidic coffee which means pure coffee watering is not the best alternative. 

Another important reminder is that your coffee needs to be plain, if you happen to add sugar or cream to your coffee, then you might want to reduce the sugar content, or not use it to water your garden plants because sugar and fat can harm your plants and invite insects, pests, ants that can cause damage. 

Diluted Coffee as Fertilizer 

You now may question the practicality of using coffee to water your plant because you need some close search related to the type of your plant and monitor it closely. You might want an easier strategy but also do not want to waste any leftovers. This leads to another solution which is using diluted coffee. 

Diluted Coffee as Fertilizer 

Diluted coffee means adding a certain amount of water to mix with the coffee that is left. An adequate amount is to have 1/4 of coffee content with 3/4 of water content. The measurement also varies accordingly to the caffeine content in your coffee as well. The aim is to have the color of a cup of tea. In this case, you do not need to worry about the sign of yellowing of your leaves, or the damage caused by acidic content from coffee at all. This strategy slightly links back to the natural way of gardening and is also ideal because you won’t have a full cup of coffee left all the time.

Recommended Steps 

As the idea of watering plants with caffeine is somewhat new, we have listed a few tips on how to water your houseplants with your remaining drink. 

Firstly, you need to do research on the compatibility of your plants to coffee. The question you might search for is whether your houseplants are acid-free or acid friendly to ensure that they won’t be damaged when you pour coffee in it. 

Secondly, if your garden flowers, vegetables are compatible then you may add coffee grounds combined with soil, compost, or fertilizer to boost the growth. 

Or, if you do not want to use coffee grounds you might want to use liquid coffee like brewed coffee. Starting off first with brewing your coffee as you like by remembering to have no sweetness in it. Then, you would dilute your coffee to an adequate measurement, the amount of water needed to always be larger and it also depends on how strong your java is.  After you dilute your drink, you may start the watering by adding it to a sprayer or a can. And this would summarize all the points you should know. 

How often should I water my plants with coffee? 

As mentioned, coffee contains acid content which is a drawback if applied in an exceeding amount which indeed will damage or kill your house garden. Hence,  applying it once a week seems to be an ideal approach as you can add some nutrition, some nitrogen content to strengthen the growing, and simultaneously save some wasting of a cold brew java.


To sum up, Yes, you can use the remaining coffee for your plants, but it needs to be applied in a rightful way. There are several steps and tips, starting with searching the characteristics of the plants to coffee, usage of coffee grounds, diluting to the right measurement, to ensure that your garden is perfectly watered. 


Water Your Garden Plants With Coffee | Problem Solved By USA TODAY Life