Coffee grounds inhibit the growth of some plants, including geranium, asparagus fern, Chinese mustard and Italian ryegrass.
Coffee grounds are highly acidic, they note, so they should be reserved for acid-loving plants like azaleas and blueberries. And if your soil is already high in nitrogen, the extra boost from coffee grounds could stunt the growth of fruits and flowers.
The main ingredient in the used grounds is nitrogen, but there are traces of the other important nutrients like phosphorus and potassium. Fresh coffee is highly acidic, so may be useful for acid loving plants like magnolias and blueberries or for gardeners wanting to turn their hydrangeas blue.
Since coffee grounds retain moisture, avoid using on plants that prefer drier soil such as cacti and succulents. Avoid using grounds on plants that prefer alkaline soil such as asparagus, beets, geranium, lavender, rosemary, and spiderwort.
Rosemary needs fertile, loose soil with a neutral pH. The plant does not like acidic soils and overwatering, so coffee, which creates an acidic environment, will be destructive for rosemary.
Coffee Grounds as Fertilizer
Used coffee grounds are actually nearly neutral in pH, so they shouldn't cause concerns about their acidity. However, be careful not to use too many coffee grounds at once. Coffee grounds can benefit drainage and aeration but the best way to enhance garden soil is when it's done gradually.
There are a select few plants that can benefit from fresh grounds—including acidity-loving Hydrangeas, Rhododendrons, Azaleas, Lily of the Valley, blueberries, carrots, and radishes—but generally, most common houseplants will prefer low to no acidity.
Coffee grounds are effective at repelling pests because of the strong smell. The smell of coffee is repulsive to many bugs and will keep them away from treated areas. Coffee grounds can be used fresh or used, but unused coffee grounds are more effective at repelling pests.
Coffee grounds inhibit the growth of some plants, including geranium, asparagus fern, Chinese mustard and Italian ryegrass. Conversely, grounds (used as mulch and compost) improve yields of soybeans and cabbage. In other cases, grounds inhibit seed germination of clovers (red and white) and alfalfa.
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.
'Coffee grounds are an excellent houseplant fertilizer due to their high nitrogen content (about 2 per cent) that releases slowly into the potting media as they decompose. However, coffee grounds have more to offer to plants than just nitrogen,' she says.
Coffee grounds contain caffeine, which is toxic to snails. When these creatures ingest coffee grounds, they become dehydrated and eventually die. Additionally, the sharp edges of coffee grounds can deter snails from crawling over them.
Banana peels can be placed directly onto pot plant soil, or around the base of your garden as mulch. As they decompose, they will release nutrients into the soil to feed plants. If using banana peels in your garden, place a single layer straight on top of the soil, being sure not to let them touch the plant stem.
Which plants shouldn't you try this with? Don't add eggshell fertilizer to plants that prefer acidic soil, like blueberries. Ericaceous plants such as mountain laurel, pieris and azaleas also fall into that category. In extreme cases, low acidity for plants could impact their overall health and/or the resulting crop.
Coffee grounds are a rich source of nitrogen, phosphorus and potassium, all favorites of orchids, and most other plants, really. They also contain a number of other nutrients which can be beneficial to plants. This means that some gardeners view coffee grounds as an inexpensive fertilizer.
Coffee's bitter compounds are responsible for its repelling effects. These compounds make the coffee unpalatable to rats and mice. They will avoid areas where there is the use of coffee grounds.
Not only do they repel mosquitoes, but also other insects such as wasps and bees. Coffee grounds are the bee's knees when it comes to staying bug bite free. Most bugs have a very strong sense of smell. Coffee grounds are very potent and even more potent once they are burned.
Other Natural Repellents
Mothballs — place them around the perimeter, and their pungent smell will repel snakes. Vinegar — mix it with water and spray often. Caffeine — sprinkle coffee grounds or instant coffee granules. Spices — chili powder and cayenne pepper work the best.
While plants need nitrogen (remember the NPK on fertilizers), too much nitrogen will create lots of green leaves but few berries or fruits. This means potassium-rich banana peels are excellent for plants like tomatoes, peppers or flowers. Banana peels also contain calcium, which prevents blossom end rot in tomatoes.
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. By mixing some coffee grounds into the soil below your tomato plants you're introducing these nutrients that the plants need to thrive.
Used Tea Bags can slightly lower the pH level in pots and provide the plants themselves with vital nutrients and minerals. Just open up the Tea Bags, sprinkle in the leaves and allow your green friends to flourish.
Whilst coffee grounds are primarily valued by rose growers for their higher nitrogen content, they also contain other essential minerals such as phosphorus, potassium and copper, all of which will improve the soil health and are valuable nutrients for roses.
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.
Yes, succulents love coffee grounds, especially when they absorb all of the nutrients that coffee grounds provide. Coffee grounds are very acidic, and succulents grow well and love acidic soil. Coffee grounds are also loaded with nutrients including magnesium, potassium, and nitrogen.
Safely Composting Banana Peels
Unless you bury them deeply, you also risk attracting pests and rodents.