Turface is calcined clay pebbles, like mini hydroton pebbles. I have a big bag of it and was wondering if anyone has used it as a seed covering grit instead of granite or coarse sand or crushed oyster shells. The particles are mostly in the 1/16" to 1/8" size range (1.5 mm to 3.175 mm). I'm going to sow seeds in deep plug trays filled with pro mix bx and then cold stratify them over the winter in a cold frame.

It ought to work fine. The only problem I see (maybe) is it is a lot lighter in weight than most other grits. Watering might move the turface around more than you would want with young seedlings.

That's a good point I hadn't thought of. I will have to test it out to see if it floats or moves too much.

It shouldn't be a problem if you mist or water from the bottom