For fleas you'll have much better results (at least I do) with beneficial nematodes sprayed on the soil. Best results occur when you apply after or near the end of a 4 day rainstorm - something that really saturates the soil.

Here are my notes on the Houston area:

Teas Nursery on Ballair Blvd. carries Bradfield fertilizer. You should call ahead because they occasionally run out.

Southwest Fertilizer, 5828 Bissonnet, has a great selection of organic fertilizers and supplies. You can also check out their website: www.yardgeek.com

Check out the links at

http://www.ag-org.com/retail.html

You can buy diatomaceous earth from any of the Cornelius (Calloway's) Nurseries in Houston. Also, you can buy organic gardening supplies from Southwest Fertilizer in Houston. Good luck.

if you are on the north side you should call RCW nurseries. they have Diatomaceous Earth (not sure if its food grade) and a knowledgeable staff that could help you out.

The original poster just wanted the kind for garden use, not swimming pool use. Now, two years later, DE is much easier to find, even in Houston.