Numbers 1-10 are USDA Hardiness Zones. (View the Zone Map)
C - Cool season grasses are the first to start growing in the spring and stay green longer into the fall. They go dormant in mid-summer unless given lots of water to keep them actively growing. Cool season grasses may be planted in early spring, summer (with extra water) or early fall; in hot climates, plant in spring , fall or winter. Sow 1/4"-1/2" deep; water to establish.
W - Warm season grasses are green during the hotter months, go dormant and turn beige when it gets cooler (also during hot, dry spells without extra water). Warm season grasses may be planted anytime except 2 months before fall's first killing frost; seed requires warm soil temperatures to germinate. Sow 1/4"-1/2" deep; water to establish. Warm season grasses are much more drought tolerant than cool season grasses & therefore a good choice.
Cold stratify or stratify refers to a simulation of a winter's cold (to break seed's dormancy) by placing seed in a plastic bag with a slightly moistened sterile medium (e.g. potting soil) & storing in the refrigerator for any given amount of time - generally 4-6 weeks.
