I don't have a garden myself, but my wife does and I help out. One of the things we do is maintain a compost pile. You can't expect instant results from it. Put eggshells in the pile, the calcium is good for plants. Also any fruit and vegatable waste from the kitchen, grass clippings and so on. Do not put meat in it. Turn it every month or so. Over time it turns into extremely rich compost you can spread in the garden. It's too late for this time of year to use it, but if you start now you'll have great natural fertilizer next year.