moisture retention

If you're growing things in containers that's an oxymoron unless you are growing things that usually grow in a swamp. Healthy container soils here in Florida must be fast draining and NOT hold moisture, for the most part, due to our high humidity, especially during the rainy season.

Read this post, then re-read it until you start to grasp the concepts of container soil dynamics...until you have these concepts down well you'll only make marginal decisions about what is an optimal container soil for your climate, environmental conditions and specific plants you want to grow.

Tom