Here's what I do and don't do.
Do's: Leave your spinach alone after it bolts.
Don'ts: Don't water it. Don't pull it up. Don't fertilize it. Just leave it alone. Pretty easy.
The spinach plants will turn brown, dry and brittle.
In the fall you will happen to walk by you spinach patch and see this!
And now you know why I have spinach as soon as the snow melts in the spring.
You may be wondering if the cold weather kills or damages the spinach. It doesn't. The spiniach just peacefully grows under the snow. Pretty easy and amazing, if you ask me.