Backyard Winter Gardening is by far the best - for the simple reason that it gives easy to follow advice on the simplest ways to grow and harvest food in the winter.
Warnock is best known for his "Forgotten Skills" books, which look at the way pioneers sustained themselves and how we can recreate these skills for modern life. So it's no surprise that the methods included in Backyard Winter Gardening are old standbys easily duplicated today. Specifically, Warnock focuses on cold frames and hot beds.
A cold frame is just a low, bottomless box with a glass lid that's set over vegetables. Warnock explains he's used many types of cold frames, including the store bought variety and cold frames made with straw bales and a piece of glass. But, he writes, his simple, inexpensive, homemade two by four cold frames work best. Happily, they are extremely simple to make and even someone without building experience should be able to create one.
The author also uses hot beds; they have the same construction as his cold frames, but before planting vegetables in them, the author puts fresh manure or green clippings beneath the soil; as these decay, they keep the temperature in the box quite warm.
Using one of these two devices, Warnock grows an abundance of vegetables in winter, including beans, cabbage, lettuce, peas, spinach, and even melons. Between these fruits and veggies and the produce he keeps in his cellar, he easily feeds his family all winter.
In addition, Warnock offers details about his geothermal greenhouse - an underground greenhouse that requires no electricity and gets quite hot (100 degrees F. or more), even in Utah's coldest, snowiest winters. Here, the author grows tomatoes year round and keeps tropical fruit trees.
Warnock also mentions overwintering some veggies. This produce isn't really growing during winter; it's just staying fresh by staying in the soil. He includes carrots, beets, and other vegetables in this list, and also shows readers how to harvest them pre-winter and store them in a cool location, like a cellar or garage. I was especially excited to see that if stored correctly in a box in a cool place, many vegetable tops will continue growing, giving fresh greens all winter.
Throughout, Warmock stresses that choosing the right seed for growing food in winter is essential. Not all varieties do well in the cold, dark months. To help readers find the right type of seed, he includes the names of some of his favorite varieties and gives advice on the best places to find winter vegetable seeds.
The only thing I feel this book is missing is some information about using tunnels for winter gardening. I do realize the author is trying to focus on the most old fashioned and easy ways to winter garden, and tunnels are more of a modern invention. But at the back of the book, the author excerpts some of his gardening journal, mentioning tunnels briefly, but never explaining why he doesn't recommend them. (Elsewhere in the book, he mentions the high winds his area receives, so I assume this is why tunnels don't work well for him. Still, it would be helpful to read what he feels the pros and cons of tunnels vs. cold frames and hot beds are.)
In addition, it's important to remember that Warnock is somewhat selective in the foods he mentions in the book. For example, he neglects to mention parsnips, Jerusalem artichokes, kale, or collards, all of which are good winter vegetables. On the other hand, he talks about his amazing trials growing cantaloupe in hot beds (!) and has a chapter dedicated to mangels, an excellent through little-known crop for livestock.
Finally, several times in the book, Warnock refers readers to his website or blog. For example, he suggests checking his blog for an update about growing cantaloupe in winter. But when I arrived at his site, the search feature wasn't working. In fact, his blog looks a little neglected, with loading problems and infrequent posts.
All in all, however, Backyard Winter Gardening is an excellent book, and I highly recommend it to those who want to grow more of their family's food.