Recycle Coffee Grounds And Keep Your Plants Happy

Published :
Categories : BlogGrowing Cannabis

Recycle Coffee Grounds And Keep Your Plants Happy

Grow organic and recycle coffee grounds to feed your plants and repel parasites. With high nitrogen levels, coffee grounds make a great vegan fertilizer.

Growing organic also means recycling. We can use coffee grounds to feed the plants, repel parasites, reduce smells, and other purposes. This abundant waste material has high nitrogen content, added with other mineral elements which plants usually like, in the right proportions. Every year, around 6 million tonnes of coffee waste is produced worldwide. The guy at the coffee bar shouldn’t have problems in filling up some bags of coffee grounds for our urban garden.

Many people simply spread dried coffee grounds all over the soil surface before rain or watering, around the plants or mixed in the soil to act as a slow-release nitrogen source. Someone might argue that most of coffee beans contain pesticides, with the exception of organic cultivations. Others say coffee grounds tend to generate mold. Let’s see some facts and figures about coffee as an organic plants’ nutrient.


According to agricultural studies and growers’ experience, coffee can be a good choice both as a standalone organic nutrient and in a fertilizing blend. Coffee grounds have a pH range from 5,8 to 6,2 which is good for cultivation. They contain more than 2% nitrogen, with 0,06-0,3% phosphorous and 0,6-1% potassium. This ratio is suitable both for vegetative and flowering phases, even if the low amount of phosphorous (in a phosphoric acid form) might not provide enough food for the demanding flowering phase. Big blooming requires phosphorous from other sources.

Most of the macronutrients and trace minerals (micronutrients) present in coffee grounds are immediately available to the plants and they are not so slow to be released, compared to other organic fertilizers. Anyway, fungi and bacteria in the soil do need their time to accomplish their job in breaking down minerals from coffee into food for plants. Coffee grounds almost don’t contain calcium, a chemical element which some plants love. In an organic fertilizing mix, egg shells would provide the right amount of calcium to combine with nitrogen from coffee grounds.

Coffee grounds are acidic but they can be rinsed with water to increase their pH up to around 6,5. You can also infuse the grounds in water, and use this tea for irrigation or foliar spray (if you believe in foliar nutrients). When they are not broken down in a composted form, coffee grounds can be too acidic for some plants, while they constitute a perfect “green part” in a compost mix.


Many experienced growers advise to use coffee grounds in compost instead of mixing them directly into the soil. In a compost system they become part of the green materials, such as fruits and vegetables, to be mixed with carbon-rich brown materials like straw, shredded leaves, eggshells, wood ashes. A mix of both green and brown is necessary for organic waste to heat up and break down into good compost. No more than 20 percent of initial compost volume should be made out of coffee grounds.

Among vegan components for fertilizing, used coffee grounds provide as many nutrients as almost all other organic fertilizers. Some animal sources bring more nitrogen and potassium in the fertilizing mix, but coffee can easily compete with most manures or other vegetable sources. When it comes to cannabis growing, some say there are better fertilizing options for this precious crop. Furthermore, mixing organic fertilizers require some skills and a lot of attention, while a wrong mix, no matter if organic or not, can seriously damage a crop. Just like with any other nutrient a grower has never used before, it is better to experiment a little with mixes and dosage before fertilizing high value cultivations. After this warning, since coffee grounds are so easily available, they worth considering some experiments with mixing and composting. Just a little extra work can save the grower some money and reduce a tiny bit the urban waste.


Coffee grounds can also improve soil texture and drainage both in pot and fields, and they are a good nutrient for useful worms when mixed in outdoor soils. Acidity in coffee grounds can be good or bad for plants but it is surely bad for some animals, especially for some few dangerous parasites. Furthermore, they are also micro-abrasive. The combination of these two features, acidity plus sharp edges, makes them very effective in keeping snails, ants, slugs and cats away from crops. A wise organic gardener will then displace coffee ground s along the perimeters of the cultivation, as a natural barrier. Some more coffee grounds left? They can be deodorants in cars and fridges, and they can be used to clean your hands after cutting onions or handling smelly stuff.


  Guest Writer  

Written by: Guest Writer
Occasionally we have guest writers contribute to our blog here at Zamnesia. They come from a wide range of backgrounds and experiences, making their knowledge invaluable.

      Find out about our writers