I too was hoping for some help. I've always had Irises but just kind of grew them with no knowledge about feeding them or their care. I just stuck them in the ground and they grew. I have about 30 varieties ordered and have been trying to get a bed ready for them. Any advice would be appreciated... I guess I'm looking for a mentor. Good luck with your bed.

If you look on the iris websites...Cooleys etc. they will have information on how to grow the irises. I did look up a local iris farm in my area and their advice to is fertilize three times a year...Valentine's Day, Labor Day and Halloween...cute, huh? I think I can remember that.
Anyway, they said irises are heavy feeders...I didn't know that. I think if you find a nursery or an iris farm in your area, they would have good advice on how to grow them in your zone...I am in California so it might be different than say Maine as far as a fertilizing schedule. As far as preparing the bed, I am not sure, but I just add lots of compost, make sure it drains well, add fetilizer to the bed as I turn the soil and make sure it gets a lot of sun! Good luck to you!