Many studies have shown that the nutrients present in coffee can be highly beneficial
Coffee can be a great nitrogen booster for plants. So, whenever you have leftover coffee put that on the roots of your plants.
Use a light hand when using coffee for your beloved plants because too much nitrogen can also stunt the growth of the plant.
There are actually two ways you can use coffee for plants. One way is diluting black coffee with water before pouring it on the soil.
Using this method, you should stick to “watering” your plants with coffee only once a week.
Another way is mixing coffee grounds with the soil.
After boiling that much needed pot of coffee you can mix the leftover coffee grounds directly into the soil, or dump it into your compost bin with other organic materials, and use it as fertilizer in your garden or potted plants after it decomposes.
Many studies have shown that the nutrients present in coffee can be highly beneficial.
Contrarily, there is a study published in the journal Urban Forestry & Urban Greening in 2016, which explained why "Applying spent coffee grounds directly to urban agriculture soils greatly reduces plant growth."
How coffee helps plants is by attracting useful bacteria to break down into much needed nutrients for the plants and warding off weeds and pesky little bugs.
According to a video story published by US Today, coffee is very rich in potassium and magnesium, which are very important nutrients for plants.
It helps to make the plants healthier and strengthen stems.
Another main characteristic of coffee is that it is acidic. For some acidic plants like roses, hyacinths, aloe vera, hydrangea among others, this can be an added bonus.
However, it might not be wise to use high amounts of coffee in plants other than the acid loving ones.
What makes coffee reduce plant growth in urban soil is caffeine.
Caffeine is known to prevent other plants from growing in the nearby areas of the plant that produces it. Plants like chocolate and coffee contain a lot of caffeine which means the area becomes hostile for other plants.
The caffeine content in coffee is so high that even after you’ve made an espresso for yourself, the coffee grounds still contains a substantial amount of caffeine.
This might not pose a problem in case of potted plants, but the scenario might be different in case of gardens and in the broader spectrum of agriculture.
Using coffee might be an easy way to fertilize the soil, care should be taken so that we do not overdo it.