Buckwheat pillows are pillows stuffed with -- surprise -- the husks from buckwheat, a grain. When packed inside a pillow, the small, triangular husks offer excellent head and neck support, and also make the pillow extremely malleable and adjustable, so buckwheat pillows are ideal for users who need just the right pillow shape to drift off to sleep.
A good indication of the current vogue for buckwheat pillows is that these pillows receive a large number of reviews from users contributing to SleepLikeTheDead.com, falling only slightly short of down pillows in popularity. According to this website's review summary, users like buckwheat pillows for their support, durability, superior air flow, malleability, and (last but not least) rock-bottom price (as little as $10 and up) compared to down and feather pillows. Buckwheat pillows are said to be especially good for back and side sleeping, though habitual stomach sleepers may be more comfortable with a softer down or feather pillow.
As cheap and versatile as they are, though, buckwheat pillows aren't without their disadvantages. As you might guess, a pillow full of buckwheat hulls is fairly heavy, and we found some complaints from users about noise when the pillow shifts ("noisy" is an adjective you don't usually want attached to your pillow). Also, because buckwheat hulls allow for good airflow, buckwheat pillows don't absorb heat as well as fabric pillows, making them unsuitable for sleepers who need that "warm as toast" feel. Finally -- and perhaps most daunting -- maintenance of buckwheat pillows isn't as straightforward as you might think; you might actually have to remove the hulls before washing the casing, depending on how your pillow is constructed.
Like memory foam pillows, buckwheat pillows resist dust mites. However, a fraction of the population is mildly allergic to buckwheat; if you fear you might be one of them, you might want to test a pillow out before buying your own (some hotels now offer buckwheat pillows to guests). If you are allergic to buckwheat husks, you may want to consider a microbead pillow, which offers a similar feel to buckwheat, but uses tiny plastic beads instead of husks. The main disadvantages of microbead pillows, according to SleepLikeTheDead.com, are their chemical odor when new and lack of long-term data about durability.