Soccer Dad - Your question goes to the heart of debate about old school organic gardening versus the more modern (easy) approach of using compost tea (aerated or not), liquid humic acid, fish goop, fertilizing with pressed alfalfa and/or soy bean meal. You may get quite a few different opinions, some opposing. So, hereÂs my answer (opinion) to your question " Is humic acid a reasonable alternative to compost ? " NO. Nothing is as good for your soil and therefore your lawn as an application of good compost. A few quarts of humic acid spread across 5000 sq. ft of lawn will not give you the organic material of 5 cubic yards of compost weighing about 10 or 12, 000 lbs.
Is the humic acid good for your lawn ? Yes, I think it probably is. Will tea add microbes to a lawn? Yes it will add some bacteria and some fungus, questionable how long it will survive though. Here is a paste from a recent response made to the Organic Lawn Forum - " Your soil microbes (Mostly bacteria) found the CGM . So you are organically feeding the soil that feeds your lawn. But for a complete meal, you soil needs compost. I know, its "old school organics" labor intensive, plus it may be hard to find good compost. Good compost will contain many many species of bacteria, fungi, protozoa, molds, nematodes, micro arthropods (bugs), worms, and other living stuff. It will contain lots of organic material (carbon) which will slowly decay into humus feeding your soil microheard over time. It will attract and feed earthworms which will aerate your soil along with the longs strands of beneficial fungus. If you feel the need to put something down every week, then Let that something be compost - " Please have a look at the link below to the Organic Lawn Faq written by a very knowledgeable person from this forum.

Here is a link that might be useful: Organic Lawn Care FAQ

Thanks. I suspected that it wasn't a cure all, but rather a complement to a complete program. It certainly could be better than nothing at all.