My parents drink coffee every morning. We have an excellent supply of used coffee grounds. If you do not drink coffee, Starbucks gives away their used grinds. If you asked, other coffee shops would probably save them for you.
Coffee grounds are a great way to fertilize your garden. They have 1.45% nitrogen which helps to enrich the soil and to grow leafy vegetables. Coffee grounds are also a good source of calcium and magnesium for your garden. Interestingly, they are not acidic after they are brewed and have a PH level of 6.9 which is suitable for most plants. Coffee grounds can be used in your compost or applied directly to your garden as fertilizer. When you add the grinds to your garden, make sure you do not cover the dirt thickly since the grinds will develop a fungal layer if you do.
The grinds also can be made into a liquid fertilizer which is called coffee tea. All you need is ½ pound of brewed coffee grinds and a 5 gallon bucket filled with water. Let it steep until you are ready to use it on your garden. If you have a busy schedule, it might be easier to “short-cut” the coffee tea process by lightly sprinkling the used grounds on the soil directly before watering.