Coffee and coffee grounds are acidic and, while there are some plants that love an alkaline soil and won't do well with the addition of coffee, such as lily of the valley, lavender and honeysuckle, some plants absolutely thrive in an acidic soil.
In most cases, the grounds are too acidic to be used directly on soil, even for acid-loving plants like blueberries, azaleas and hollies. Coffee grounds inhibit the growth of some plants, including geranium, asparagus fern, Chinese mustard and Italian ryegrass.
"It's fine to use coffee as a fertilizer," our senior lab testing technician, Jonathan Chan, says. "However, you should be careful because coffee can raise the acidity of the soil. Caffeine also is known to have a negative effect on plant growth."
Apparently, coffee is a great source of nitrogen, and plants that enjoy more acidic soil can benefit from certain levels of nitrogen, like blueberries, azaleas, and rhododendrons. According to The Spruce, if you plan on doing this, you'll need to keep a close eye on your plant.
Some plants tolerate an acidic environment very well, but there are also those for which the acid will be poison. Plants such as sago palm, yucca, etc., will not become friends with coffee grounds.
Some gardeners report success in turning their hydrangeas blue by applying coffee grounds to the soil. The coffee grounds make the soil more acidic, allowing the hydrangea to more easily absorb aluminum. In addition, fruit peels, lawn clippings, peat moss and pine needles, are thought to have a similar effect.
Caffeine will definitely harm your succulents, so this is why it's very important to dilute the coffee grounds with water. Definitely use coffee grounds for any type of succulents that you want to grow! Your succulents will get so many nutrients from coffee grounds it's amazing!
Yes, coffee contains nitrogen, but in small amounts that are unlikely to make much of a difference to either your best indoor plants or your garden borders. If you do decide to occasionally use coffee to water your plants, make sure it's black, without any sugar or milk added.
Every time you water your Pothos, the nutrients of the coffee get released in the soil, providing your plant with the building blocks it needs to grow! Sprinkling coffee grounds on top of your Pothos' soil will also help keep houseplant pests at bay.
Coffee grounds contain around 2% nitrogen as well as varying amounts of phosphorus and potassium which are all very important for the growth of tomato plants.
The absorption of these nutrients encourages more rapid growth in the plant. Therefore, pouring soda on plants, such as Classic Coca Cola, is inadvisable. Coke has a jaw dropping 3.38 grams of sugar per ounce, which would certainly kill the plant, as it would be unable to absorb water or nutrients.
Strawberries are acid-loving plants, and coffee grounds are acidic. Adding coffee grounds to the soil can help to lower the pH of the soil, making it more acidic and suitable for acid-loving plants such as strawberries, azaleas, lilies, rhododendrons, and roses.
Most bugs have a very strong sense of smell. Coffee grounds are very potent and even more potent once they are burned. The strong scent and “smoldering effect” will fight off pests and keep them away.
Since coffee grounds have such a pungent and intense smell, mosquitoes do not like to come near it. Mosquitoes are repulsed by all types of coffee, whether it is fresh, used, or burnt. The most effective way to use coffee grounds for mosquito control is by burning them, as it creates a stronger aroma.
Epsom salt can improve the blooms of flowering and green shrubs, especially evergreens, azaleas and rhododendrons. Work in one tablespoon of Ultra Epsom Salt per nine square feet of bush into the soil, over the root zone, which allows the shrubs to absorb the nutritional benefits.
The organic contents of cinnamon are perfect for increasing the root growth of plants. This spice's auxin content works to help the stem cuttings or seedlings sustain growth, all while protecting the plant with its antimicrobial and anti-bacterial qualities.
But the reasoning behind using banana water is sound: Bananas contain a lot of potassium, which is an essential macronutrient that boosts plant growth, strengthens stems and helps plants better resist drought and pests.
The shells also contain other minerals that help plants grow, including potassium, phosphorus, and magnesium. Eggshells are, therefore, an effective and inexpensive fertilizer for outdoor garden soil and houseplants.
Used coffee grounds are great for succulents like jade plants that grow in slightly acidic soils. Coffee grounds also contain two crucial nutrients; magnesium and potassium. However, coffee grounds should be heavily diluted and used sparingly with jade plants because the grounds are high in nitrogen.
There is one more trick up the apple cider vinegar sleeve: You can actually change the color of hydrangea flowers from pink to blue. Hydrangea flowers will be pink in alkaline soil, but change to blue in acidic soil. So, mix up some apple cider vinegar and water, and give all the acid-loving plants a treat.
Avoid giving coffee to geraniums. You can also pour leftover coffee onto your compost pile. Once you begin watering houseplants with coffee, watch them closely. If the leaves begin yellowing or their tips turn brown, it might be a sign that the coffee is making the soil too acidic.