You can mix coffee grounds with your soil to improve aeration. Coffee grounds attract earthworms and earthworms loosen the soil by burrowing through it.
Coffee Grounds as Soil Amendment
You may consider growing your tomato plant in coffee grounds granted such coffee grounds have a slightly acidic or neutral pH.
Coffee Grounds Are Good for Tomatoes
Coffee grounds are very good for pepper plants. They can provide up to 60 days of nutrient coverage for pepper plants.
Growing Pepper Plants in Coffee Grounds
Applying coffee grounds to the soil as mulch is a good way to prevent or kill weeds. With light and air blocked out, the seedlings/seeds of weeds should not grow.
Coffee Grounds as Weed Killers