Most sources recommend planting in furrows 4" to 6" deep. 8" is deeper than what I've seen recommended. If your soil is light and well draining, you should be fine anyway. If you have heavy clay soil, 8" may be a little deep.

Well, I googled it just to see what some other sources said. Some sources do recommend 8" deep furrows. Here's a pamphlet from the University of Tennessee that recommends 6" to 8". I wouldn't worry about it at all. Sounds like you are in range.

Here is a link that might be useful: UT Ag Extension Pamphlet

Thanks! I was dreading having to dig up ALL those plants!!!!!

I did amend the soil in a big way -- added sand, compost, new garden soil for vegetables, etc. It is nice and fluffy and should have good drainage.

Whew!