The primary planting season for gardeners in the Southwest desert is October through February. This means that February is the last optimal month for planting our cool season vegetables. The vegetables listed are the varieties that are suited for our cool winter climate. If you love fresh lettuce, spinach and bok choy, they should be planted now to ensure their full life cycle. That is, before the warmer and longer days of spring arrive and trigger the flowering and end of the plants production.
In the Phoenix area the last frost date averages around the 15th of February. Although there have been freezes as late as early March. This is the time of year that a new season of planting begins and a new variety of vegetables can be planted. The warm weather vegtables will be listed in addition to flowers and herbs, these can be planted as early as the 15th of February.