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.
Diluting brewed coffee with an equal part water is plenty to do the job. Coffee grounds have been recommended in the past as an organic method to keep slugs and snails out of your flower and vegetable beds. Grounds will repel slugs, but the USDA research team confirms that a caffeine solution is more effective.
They noticed that a 1-2% caffeine solution killed nearly all the slugs and snails within two days. Concentrations as low as 0.01% put the pests off their dinner. A cup of instant coffee contains about 0.05% caffeine, and brewed coffee has more.
It is also suspected that the smell of coffee alone deters snails, as they have a sensitive sense of smell and coffee scent does not appeal to them much. Important: Caffeine has a highly concentrated non-directional harmful effect on most living organisms.
Sage, rosemary, parsley, and thyme are all beautiful additions to your garden and also deter snails. Plant them in a border around your garden and between vulnerable plants to ward of slugs and snails. It also means you get a beautiful, additional herb garden to use in your cooking!
Slugs and snails hate copper because it causes a harmless electric shock-like reaction when they come into contact with it, so they crawl away. Copper with +2 ions carries a charge that interferes with a mollusc's slime, which they don't like and thus avoid.
Coffee grounds are rich in nutrients, especially nitrogen. They also have some amount of other nutrients like potassium and phosphorous. Overall, this means that adding coffee grounds to your garden can work fairly well as a fertiliser. Coffee should be spread in a thin layer, rather than being clumped in one place.
To do this, you do not need anything extra. Just sprinkle used tea leaves around your plants to deter slugs and snails from eating them. Although there are many natural ways you can deter slugs from your garden, the best way is to create a space that isn't hospitable to them.
"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."
Cinnamon
To deter slugs, simply sprinkle a layer of cinnamon around the base of your plants and leave. This will stick to the slugs' bodies if they start to cross the line, prompting them to turn back – reapply after rain.
Garlic, Lawn Chamomile, chives. Some plants repel most slugs and snails and these may have a deterrent effect when planted alongside or used to make an extract. Many gardeners swear by garlic as a natural pest control. Some say chives are effective it the leaves are tied around vulnerable plants; sounds fiddly.
You can pick off snails at any time of day, but at night they are more likely to be found. Shine a torch on vulnerable plants and vegetables to find them and dispose of them in a hedgerow or waste ground. Use a scratchy barrier.
Barrier Method: Make a line of Epsom Salt around the edge of your garden, creating a barrier around the perimeter. Slugs and Snails will not cross this barrier because if they do, they will not survive.
Caffeine in large doses is said to be toxic to slugs, and in smaller doses it can slow them down. It has also been noted that the mere smell of coffee deters slugs and snails. In addition, others state that ingredients in the coffee grounds stimulate their mucus production. This would deter them from crawling over.
Plants that slugs hate
As well as those with tough leaves or woody stems that they find difficult to chew. The robust lacy fronds of shade-loving ferns and thick leaves of Geranium, Bergenia (Elephant's ears) and Saxifraga × urbium (London pride) are all too thick for them to sink their teeth into.
A spray bottle filled with plain white vinegar is a great cure for slugs that aren't on plants. An extremely effective mollusk dissolver, vinegar is also an herbicide-so don't spritz the salvia. 15) Or Garlic.
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.
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.
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.
Spraying WD40 on the outside of pots or planters will make them too slippery for slugs to climb. This can be effective for pots and planters that sit on a path or patio, but should be kept away from soil or other plants.
Line your borders with upturned eggshells. The sharp edges will stop slugs sliding past as they don't like the feeling. Create a rough area around your plants with sand or gravel to make it harder for the slugs to reach the plants they have their hungry eyes on.
- Some people have used talcum powder, lime, or wood ashes as a barrier. However, if using ashes, don't let it touch the plants.