It got too warm for them most likely. They're a cool weather crop. You can eat it, but it may be bitter.

I've tried Spinach in the South Sound for several years now. It always bolts (or tries to bolt) when you start hitting the 70's regularly. It is a cool weather crop.

If you seed again in early August, you may well get a nice fall crop.

If you were planning to cook the stuff rather than use it for salads, I'd recommend growing chard instead which seems about as foolproof of a veggie as I can get for my garden.

No use cutting off the tops. If it's bolted, it's going to be "edible," but you surely wouldn't want to eat it.

There are some spinach varieties that are fairly bolt resistant, but, really, your spinach is never going to make it through the summer. You're lucky our summer has been so cold, or it would have bolted a while ago. (In fact, mine bolted some time ago -- I'm letting it go to seed.)

Mine did the same thing. It doesn't wait for it to get warm. It pokes along for a while, then it bolts before it gets big enough to bother harvesting.

I was told by a wholesale nursery owner here in Olympia that our typical glacial gravelly tills just don't have enough organic matter in them for leaf crops like lettuce and spinach and that's why they bolt and they taste bitter even before they bolt. I'm working on adding more organic matter but apparently still don't have quite enough.

A week without water can do it too. Once they bolt, they're bitter as all get-out.