Adding organic material to your garden is a great start. There is more that you can do to support the health of your soil and it doesn't have to cost very much. They are items that are commonly found around the house or picked up at the grocery store:
Epsom Salt: Yes, the stuff you keep on hand for soaking wounds. This is magnesium sulfate and will help your plants grow strong and green. You can mix it well into the soil in the spring to help get plants started, or dissolve with water in a hose-end sprayer and spray the plants every few weeks.
Ammonia: This can be nasty stuff in large quantities, but a little goes a long way in the garden. Ammonia is nitrogen, one of the most important substances to having a healthy garden. Master gardener Jerry Baker calls ammonia "thunderstorm in a bottle." Mix two ounces with a gallon of water and apply to soil. For larger coverage, one cup in a hose-end sprayer to apply to the entire lawn and garden every few weeks. The caution here is to not overdo on fruits and vegetables or you may end up with great looking, leafy plants that are not bearing. It is a case of a little is good, but more is not better.
Coffee Grounds: Used coffee grounds make a great soil amendment for nitrogen. If you are a coffee drinker this is a great way to recycle all of those leftover coffee grounds. If, like me, you are not a coffee drinker many coffee houses are quite happy to save grounds for you. The Starbucks in my grocery store will save grounds for me. One of their employees lives in my neighborhood and has dropped grounds off for me. Any grounds I still have beyond soil amendment go into the compost bin. If you really don't like anything about coffee, be forewarned, your garden will smell like coffee for weeks.
Baking Powder: This is a great, simple way to add calcium to the soil. This is especially for plants prone to blossom end rot. For me and my neighbor this has been an ongoing issue with our tomatoes. So far the jury is out on how well this works, so I am placing this particular soil amendment into my "experimental" category for another year.
As I mentioned in my previous blog on soil, much of my garden is in patio pots. It may have been noticed by some that I did not mention using potting soil for this. One of the reasons that I do not use commercial potting soil is because I can mix my own to the specifications I select, and I can alter them from pot to pot based on what I will be planting.
The agricultural extension office for Colorado at Colorado State University has an excellent article on soil amendment.