Coffee grounds improve the soil by adding nutrients. It provides nitrogen – a classic ingredient in most fertilizers that plants need to grow. Furthermore, it contains organic ingredients such as potassium, magnesium, calcium, phosphorus and minerals that help plants develop green leaves and strong stems. But do you know how to use coffee grounds as fertilizer and for which plants? Read on to learn which plants like used coffee grounds and what to look for when using them as fertilizer.
Table of Contents
- How to properly use coffee grounds as fertilizer and for which plants.
- New and old coffee grounds – which is suitable for which plants.
- What types of plants like coffee grounds?
How to properly use coffee grounds as fertilizer and for which plants
Coffee grounds are an excellent fertilizer for agricultural crops, houseplants and garden flowers. However, you must use coffee grounds properly if you want to achieve optimal results with your plants. First, remember that coffee grounds are “green compost.” This means that you need to add “brown compost” or carbon-rich organic material to your used coffee grounds to provide your plants with a balanced nutrient. However, you should also keep in mind that there is a big difference between new and used coffee grounds.
New and old coffee grounds – which is appropriate for which plants.
Unused, raw coffee grounds have a pH below 5. This is very acidic and lowers the pH of the soil . Used coffee grounds have a nearly neutral pH, ranging from 6.5 to 6.8. You have washed away all the acid in your coffee. So you are not increasing the acidity of the soil. In very acidic or alkaline soils, they actually cause the pH to approach neutral.
This means you can use used powder for almost any plant, but new coffee only for acidophilus that like acidic soil, such as azaleas, rhododendrons, camellias, veresias, nasturtiums, hydrangeas, ferns, hollies, gardenias, and caladiums. Most vegetables like slightly alkaline soils, but acid-loving vegetables such as radishes, parsley, potatoes, peppers, and rhubarb can be helped by fresh coffee.
Similarly, many fruit trees prefer neutral soils, but raspberries, blueberries, gooseberries, cranberries, and black currants appreciate some acidity.
What types of plants like coffee grounds?
Plants that like used coffee grounds fall into four categories:
- Garden plants, especially acid-loving plants such as azaleas, camellias, daffodils, lily of the valley.
- Vegetables such as tomatoes, potatoes, radishes, broccoli, peppers, rhubarb.
- Fruit bushes like blueberries, cranberries, raspberries.
- Houseplants like rhododendrons, African violets, Christmas cactus, jade plant.
Let’s take a closer look at some of them.
Used coffee powder makes these garden plants very happy
- Azalea and rhododendron (Rhododendron spp.)
Azaleas and rhododendrons are the same genus of plants, but azaleas are particularly difficult to cultivate in the garden. They are beautiful, but generally more delicate than rhododendrons. One of the tricks to keeping azaleas happy is to have a very nutrient-rich soil, but also very, very loose and well aerated! They also like very low soil pH – between 4.5 and 5.5. All this must be combined, otherwise they will become sick and weak. Their roots are sensitive and can not break through heavy soils. Coffee grounds make azaleas and rhododendrons very happy, and they reward you with bright colors!
- Hydrangeas (Hydrangea spp.).
Unlike azaleas and camellias, it is not very sensitive and can grow in a variety of conditions, preferring acidic or neutral soils.
But if you want your hydrangea to be at its best, a good dose of used coffee powder at the base of the plant can go a long way!
Used coffee powder as fertilizer for tomato and vegetable gardens.
You can also use used coffee powder in your vegetable garden. Most vegetables like the added nutritional value of used coffee grounds, but few can compete with fresh coffee grounds. This is because most vegetables prefer a relatively alkaline, or neutral to alkaline, soil pH.
⦁ Tomatoes (Solanum lycopersicum).
Tomatoes need a lot of energy to grow, and coffee grounds are very welcome there. Every gardener knows that tomato plants eat a lot and drink a lot and need all the help you can give them. So sprinkle little used coffee grounds around each tomato plant when the first fruits appear, and then once or twice more as the fruits bear.
Blueberries and raspberries like fresh coffee.
For best results, use used coffee powder on acid-loving small shrubs. Blueberries and raspberries are the plants that respond well to coffee grounds, but not larger trees like apples or plums.
⦁ Blueberries (Vaccinium spp. or Cyanococcus spp.).
They are acid-loving, which means they also like fresh, unused powder. These plants will serve you for many years. Give them some coffee in the spring at the beginning of the growing season, then again when they are bearing fruit, and again when the fruit is ripe. The used coffee grounds will add to the juiciness and freshness of the dark berries!
Coffee grounds as fertilizer for houseplants
Many houseplants are happy to receive a pinch of coffee grounds. However, be careful! The pot or container has very little space and a limited ecosystem, so you should only use tiny amounts.
⦁ African violet (Saintpaulia ionanthia).
African violets are so cute, with their fleshy leaves and bright colors! However, it’s not easy to keep them in such good shape in a small pot. Sprinkle your violets sparingly with used coffee grounds, especially if you see them lacking energy and vitality. They will appreciate it and revive as soon as possible.