Red vs. White
As it turns out, white wheat is no natural thing. The Fresh Loaf tells us this: "Hard white wheat was developed from hard red wheat by eliminating the genes for bran color while preserving other desireable characteristics of red wheat. Depending on variety, red wheat has from one to three genes that give the bran its red cast; in contrast, white wheat has no major genes for bran color. The elimination of these genes results in fewer phenolic compounds and tannins in the bran, significantly reducing the bitter taste that some people experience in flour milled from red wheat. Nutritional composition is the same for red and white wheat."
Spring vs. Winter
In areas with those puritanical and wider ranging seasons familiar to early American settlers, these two types of wheat are traditionally planted in accordance with the name given to them. Spring wheat is planted in the spring, and harvested in the fall, while winter wheat is planted in the fall after harvest, lies dormant during the coldest winter months after sprouting, and then continues to grow in early spring and is harvested soon after. Because of our so-called "Mediterranean" climate here in SoCal, we can plant spring wheat during the winter, when there is beneficial rain; and this is exactly what we did. For this reason, spring wheats have generally dominated California wheat production, especially in the north, and especially hard red spring wheats, which are very popular for bread production. (Hard red winter wheat is what most all-purpose flour mostly contains). Most of our varieties are indeed spring wheats, with only a few of the test plots containing winter varieties. It will be interesting to see how the winter and spring wheats grow side by side.
Soft vs. Hard
Wheats could all theoretically be judged on a scale which determines their protein (and therefore gluten-producing) content. This is the distinction which "soft" and "hard" are trying to make. Softer wheats have less protein and are generally used for pastries and the like. Furthermore, they are almost all winter wheats. Hard wheats, because of their ability to develop gluten, are traditionally used for bread. Most of our varieties, as is to be expected, are hard wheats, and so will function better in the context of yeasted breads.