Zones 3 and 4

-40 to -20 (average annual extreme minimum winter temperature, per the USDA definition of each zone)

If you live in zones 3 or 4, winter is the main limit on your garden. Perennials, shrubs and trees must be rated hardy to your zone or colder, and the frost-free window for tender crops is short. Success comes from choosing tough plants, starting tender crops indoors, and using mulch and snow cover to protect roots. Spring arrives late, so give soil time to thaw and drain before working it.

["Short frost-free season for tomatoes, peppers and other tender crops", "Frost heaving of shallow-rooted perennials in freeze-thaw cycles", "Snow and ice damage to evergreens and shrubs", "Rodent and deer browsing under snow cover", "Salt damage along roads and walks"]

Choose plants rated for your zone or colder. Start tender vegetables indoors and plant after the local last frost date. Cold-hardy crops such as peas, spinach and lettuce can go in earlier. Plant trees and perennials early enough in fall for roots to establish before the ground freezes.

Cool-season grasses such as fescues, perennial ryegrass and Kentucky bluegrass are the usual choices. Fall is the main window for aeration, overseeding and feeding. Winterize irrigation before hard freezes.

Mulch tender perennials after the ground begins to freeze, protect young tree trunks from rodents and sun scald, and plan winter tasks around indoor seed starting and tool care.

Zones are based on winter minimum temperature only. Check your local average last spring frost and first fall frost dates with your state cooperative extension office, and remember that microclimates can differ by a half zone or more within one property.