Liquid fertilizer has to be used every other week to keep the lawn green. The problem with them is you only get a few ounces of fertilizer with each spraying. Real fertilizer, that which goes on by the pound, will keep the grass and soil healthy for weeks and sometimes months.

Their Aerify product is recognized as being good for softening hard soil. Most people call it compacted, but it is simply hard for any number of reasons.

oh ok, I didnt realize liq fertilizer had to be applied so often. I was interested in it because it was organic and easier to apply with a hose pipe. Anyway, maybe I will buy some just to try and see how it goes. I am a new home owner and taking care of such a large area of lawn seems a little daunting to me. Its so daunting that I have started reading lawn alternative books and thinking of replacing the lawn with something else.

The Soil Food Web, those wee critters that live in our soil and digest the organic matter in our soil which is then converted by them into nutrients the plants we grow utilize, cannot live in a soil that lacks adequate levels of organic matter. Spraying liquids will not provide enough organic matter to soils to make much difference. Compacted soils are compacted because of a lack of adequate levels of organic matter and while spraying some liquid, that is really a soap that reduces the surface tension of water so it can flow eaasier, does not replace the organic matter all soils need to be good healthy soils.
Spraying liquid on your soil does not replace the needd organic matter and when sufficient levels of organic matter are reached and the Soil Food Web is active those liquids will not make any difference.

Here is a link that might be useful: The Soil Food Web Primer