Things We Learned Today

By Meryl

Here’s where urban gardening gets tricky. Not only do we urban gardeners need to plant according to level of shade versus sun as well as amount of space, but we also need to plant according to zone. Basically, what zone you’re in determines which plants will thrive in your urban garden and which will most definitely not.

The USDA Hardiness Zone Map divides North America into 11 separate zones. Each zone is 10°F warmer (or colder) in an average winter than the adjacent zone. To determine your zone, enter your zip code into a USDA Hardiness Gardening Zone Finder. The continental U.S. contains six zones from Zone 3 to Zone 10. Zone three, which dips down from Canada, is best for plants that can withstand temperatures as low as -30°F or -40°F with the last frost-free date landing in mid-June. Plants in Zone 10, in the lowest parts of Florida and Texas, enjoy temperatures as low as 30°F or 40°F and a last frost-free date in February.

It’s helpful to know your zone in case you seek help from online gardening groups—they’re just as interested in your zone as your name. Once your zone is determined, you can buy plants with the appropriate hardiness for your garden. For example, plants for Zone 6, which runs across the middle of the country, include black-eyed Susans (pictured), lilies and violets. Whatever you do, before you go planting a begonia in cat’s claw land, determine your zone.