Growstone is like a substitute for perlite or pumice. I use it and like it but I use it in soil. Why would use use grit and turface? Just use a good potting soil and add growstone.

I was trying to go for Al's Gritty mix but have growstone and did not want to buy perlite or grit. It says that growstone is similar to turface so I though It might cause it to hold more water.

Use the Growstone if you have it. Growstone has as much or the same air and water holding capabilities as perlite. It would be a good substitute. Sizes of particles are one of the big factor. All similar.

We have to remember that not everyone here can grow in the same media and many can use a cactus or free draining potting mix with added aeration. Where we reside and conditions being given are all important factors.

Rick

There are almost as many medium compositions here as there are people. Because of where I reside, I have found that my plants prefer a rich potting soil. Last year, I tested a theory of mine, and left the pots of less than two year old plants in deep drip pans all summer - the pans were filled with water. They all did fine, so this year, I have them once again sitting in about 2" of water.

Even our grow zones vary within each number. So I will just have to keep an eye on things to see what my plants do.