Yeah, Clint's right. When you said grower I was thinking another CPer. Unless you're 100% sure there is no fertilizer in the mixes don't use them. Plus what kind of sand? Horticultural or pure silica should be okay. Anything else, no good.
Hint! Hint! - you can plant them in 100% live Sphagnum moss or LFS or a mixture of the two.