Place buckwheat groats into a bowl and rinse, changing water several times, until the water becomes relatively clear (I find that it's easier than rinsing in a sieve under running water).

Transfer rinsed buckwheat groats into a quart mason jar, and fill the jar with filtered water. Cover with a sprouting lid like this, and leave at room temperature for 6-8 hours.

At the end of that time, drain the water through the lid and rinse a couple of times (filling the jar with water and draining). Buckwheat releases pinkish slimy mucilage during soaking.

Tip the jar onto the side, making sure that at least half the lid is not covered by buckwheat. Leave at room temperature for 6-8 hours. At the end of that time, you should see the tiny sprouts appearing. If there are no sprouts, drain/rinse/tip on the side and leave again for 6-8 more hours. If you don't see sprouts by the end of that time, your buckwheat groats might not be able to sprout because of the way they were pre-treated (steamed or heat dried).

Once again, rinse well to get rid of the mucilage. You can use sprouted buckwheat now to add to salads, smoothies or breakfast bowls. Or you can proceed with drying them:

Place groats on a jelly roll pan lined with parchment paper (or a dehydrator tray). Dry at the lowest temperature of your oven for 1-2 hours, or according to manufacturer's instructions of your dehydrator.