Besides compost, what are some good garden soil additives and where can I get them?
Depending on your soil, most additives are available at a local garden center. You first need to decide what your soil needs. Take a good sized sample with your and the garden center might be able to help you. Don't go to Lowe's or Home Depot; they don't know jack about conditioning soil. Go to a locally owned and operated real garden center. Most often, dehydrated cow manure is a good one. Once again, the stuff the big box stores sell is worthless, it's already got all the good out of it. Leaf compost will help loosen the soil but if you use leaves, you will need to use some lime. If you can get it, mushroom house soil is wonderful stuff. It's sterilized chicken manure, shredded corn cobs and peat moss. But that's not available in all areas of the country. Rabbit manure is great! It won't burn your plants and doesn't stink to high heavens. If you know someone who has pet bunnies, get them to start saving their stuff in clean cat litter buckets so you can dump it on the garden and then till it in next spring. A little straw or wood shavings won't hurt a thing either.
There are many additives for soil. Some can completely change the state of your garden and some are just snake oil without any function but they are all designed to add to your soil what it is lacking. Before you spend any money on amending your soil you want to know what kind of soil you have and what it's missing. You can't fix your car without first knowing the problem and parts you'll need, same goes for soil. If you are partially interested in your garden you could add manure which is a lot like compost. You could get ahold of some topsoil and add that, you could also turn in a couple bags of miracle grow potting soil or a hand full or two of ozmocote. But if you are very interested and curious to know your soil invest in a cheap soil test kit. Knowing the type of soil you have, it's Ph and nutrient content is like knowing your kid's medical needs. You'll be able to buy exactly what you need to maintain a healthy growing medium.
You would always want to mix your soil together so it is fairly consistent throughout your bed so you did the right thing. I would think that the only time you would spread a layer on top would be over your lawn. In that case you wouldn't want to smother your lawn so you would use no more than an inch of compost. You may not have to add any fertilizer since you have so much compost. It may be a bit rich with nutrients for some vegetables because there is so much compost and the ingredients in the the potting soil is not mentioned. The consistency of the soil sounds lite and fluffy. That is good for a raised bed. You may want to contact a garden center that sells just plants and trees and speak with one of their professionals. You may want to get the nutrient level tested. They sell test kits or they may be able to do it for you. My only concern with your mixture would be the level of different nutrients. As an example if the nitrogen level is too high for tomatoes, you would get a lot of foliage and no tomatoes. You probably have very little to worry about and you may have the best soil but I would still get it tested this time. You wouldn't need to in following years.
