The short answer: unwashed coffee grounds will lower the pH level of your garden (raise the acidity), which is great for plants that like acidic soil, but hurts plants that prefer less acidic soil. Washed coffee grounds have a pH level of 6.5, which is almost neutral. Do indoor plants like coffee grounds? Peppers like nitrogen and coffee grounds are full of it. If you are an avid coffee drinker and hate the thought of throwing away those old grounds, donât worry â â¦ Remember that coffee may be "feeding" a plant but must also be counted as irrigation, especially for plants that don't like much irrigation. Why do I keep warning you not to put coffee grounds on your plants? Using free coffee grounds seems like the perfect solution, but some gardeners have found that using coffee grounds directly on the soil has had a disastrous effect on plants. Other Uses for Coffee Grounds in the Garden Coffee grounds arenât just for growing vegetables, they make a â¦ As much as we like to think caffeine was created for humans, evolution had other ideas. The grounds â¦ Popular plants, such as jade, pothos, African violets, spider plants, flowering cactuses such as Christmas cactuses and other flowering plants such as roses, hydrangeas, tomatoes and blueberries all like fresh brewed coffee as opposed to left over coffee grounds. I donât like it quite that much so I place two or three cups of grounds at the base of each plant â¦ This is not good for your plants or the other soil biota. You can mix the grounds into the soil or spread them on top. However, tomatoes do not like fresh coffee grounds; keep them out of that area of the garden. All in all, coffee grounds are good for vegetables and other plants, as they encourage the growth of microorganisms in the soil and improve tilth. Anything that compacts will reduce the amount of water/rain and air reaching the soil. While used coffee grounds are only slightly acidic, fresh (unbrewed) coffee grounds have more acid. Science tells us caffeine was first a mutation in plants which was accidentally copied and passed on. You can even water your plants using coffee. A common misconception about coffee grounds as a fertilizer is that it â¦ A: Coffee and tea grounds are an acidic, organic matter, so they are excellent soil amendments for acid-loving plants such as azaleas and gardenias. Coffee grounds are a great source of natural nutrients that plants need. However this seems to be linked to using thick blankets of it to mulch around plants and over seeds. However, when applied to houseplants bound by the constraints of pots, coffee grounds can do more harm than good. Know your plants' watering preferences and count cups or half-cups of coffee from whatever water you would otherwise provide. Coffee grounds are quite fine, and as such they compact easily. Your acid-loving plants like hydrangeas, rhododendrons, azaleas, lily of the valley, blueberries, carrots, and radishes can get a boost from fresh grounds. Just make sure to limit your coffee quantities, as too much caffeine can stunt plant growth and increase the risk of fungal diseases. Because as we all know, coffee is caffeinated. Yes! While this list can be heavily expanded, you want to make sure that youâre also educated in plants that do not like coffee grounds. If you have a lot of grounds (I do love coffeeâ¦) you can use it as a mulch. Watering with Coffee. Coffee grounds can be especially beneficial to houseplants when used as a mulch, pesticide, compost, or fertilizer. Find out how your plants like to take their coffee: brewed or ground. You may have heard that coffee grounds will alter the pH level of your garden. Coffee grounds are an excellent free source of nitrogen, an element all plants need. Coffee Grounds are organic, and will slowly decompose in the gardenâsounds like a good mulch. Mixing this natural soil enricher with the wrong plants can inhibit seed germination and even keep your plant from growing.