Extrapolating from the date of your post, I suspect that you planted them too late. In most zone sevens in the east, they are planted in early March. They are a cool weather crop that will not tolerate heat. Like most Chenopods, they do prefer a more neutral soil than most vegetables, so the peat could have something to do with it.

I'd agree with the too late planting. Much earlier planting next year should resolve your problem. We plant them around mid-March here same time as cabbage and potatoes. Also make sure they don't get too much nitrogen or you end up with great tops but no roots to eat.

Dave

You could try again now for a fall crop.

Also important to thin. Since you plant little fruits, multiple seedlings emerge in each place. If you don't thin them, then the beet roots won't form properly. I learned that the hard way last year.

Susan

i planted beets two weeks ago from seed here in LI... have lots of sprouts... and hope they make it.

i also seeded SPINACH around aug 10, for the cornell coop said the latest time to plant spinach here is aug 20.. well, this was a big mistake... the spinach came up, but went right to seed (bolt). the cornell coop info is mostly wrong for the locale.

You could be correct about too late. I planted them end of May / beginning of June. As well, I was late in thinning. I'm about to plant the fall crop right now. I bought the seeds from Westcoast Seeds. From their info:
"Start beets mid-April through mid-July on the Coast. If planted too early (in cold soil) they will bolt."

I'm on the westcoast in Vancouver, and the seed company is local. I'll call them and also ask them what's what.

cheers