I just purchased seeds for 5 heath species (e. glandulosa, e. mammosa, e. versicolor, e. baccans and e. plukenetti) from a site with very reasonable prices (Fine Bush People). Tomorrow I'm going to buy e. vagans, e. cinerea, e. x stuartii, e. carnea, e. tetralix and a couple of calluna vulgaris cultivars from Heaths and Heathers.

Please tell me: 1) how far apart should I plant these different species so they won't cross-breed, 2) are these suitable for growing in zone 7a and 3) what's the best way to acidify my very alkaline soil. Could I just fill the plant hole with peat moss rather than the soil I took out?

I'm fairly new to gardening in general. I hope you don't mind the questions. Thank you in advance.

I am a member of the Northeast Heather Society, a chapter of the North American Heather Society. These organizations are dedicated to the growing of heathers (Calluna, Erica, Daboecia, Cassiope, Phyllodoce and Andromeda).
To join the NEHS and get the informative newsletter, send $15 to our treasurer: Vivagean Merz, 55 Upland Avenue, Falmouth, MA. 02540.
The heath species for which you bought seeds are not included in our interest, and I don't know anything about them.
The Heaths and Heathers catalog is an excellent source of information.
The calluna and erica will not cross breed, and it's unlikely that the individual cultivars will hybridize, although occasionally a sport is found.
Erica carnea and E. vagans will tolerate alkaline soil. To acidify, you can mix dampened peat moss, shredded oak leaves, pine needles and the like with your soil.
Good luck, and enjoy your new hobby.