If you have not already go back to the Organic forum and find the FAQs. Near the bottom is the Organic Lawn Care FAQ. It talks about corn meal but SBM is fine. I just get corn meal cheaper and SBM is not available at any price to me.

Don't know how much lawn you have but the app rate for compost is 1 cubic yard per 1,000 square feet. Shovel it out and sweep it in. You can also use a leaf blower to get it off the top of the grass.

What your builder did is par for the course. It might work fine for you. Do you know what kind of grass it was? The key to fixing the underlying soil is the organic materials. The key to fixing the grass is getting enough of it. If he laid fescue, then you might need to over seed every fall. If he put a mix with Kentucky bluegrass, then you should not have to worry about it becoming dense.

Organic lawn care is not that steep of a learning curve. Just stop chemicals and start with meals. The rest is the same. Here are the 123 of lawn care.

2. Water deeply and infrequently. Deeply means at least an hour in every zone, all at once. Infrequently means monthly during the cool months and no more than weekly during the hottest part of summer. If your grass looks dry before the month/week is up, water longer next time. Deep watering grows deep, drought resistant roots. Infrequent watering allows the top layer of soil to dry completely which kills off many shallow rooted weeds.

3. Mulch mow at the highest setting on your mower. Most grasses are the most dense when mowed tall. Bermuda, centipede, and bent grasses are the most dense when mowed at the lowest setting on your mower. Dense grass shades out weeds and uses less water when tall. Dense grass feeds the deep roots you're developing in 1 above.

4. Fertilize regularly. I fertilize 4 times per year using organic fertilizer. Which fertilizer you use is much less important than numbers 1 and 2 above.
   

Thanks for the detailed response! Our grass is a KBG/Fescue mix, I think. I'll be trying out these steps this year and hope to see some good improvement!