Photo by Stevep2008
As a new gardener, one of the first things that you’ll be hearing about are growing zones. People mention them over and over in garden centers, seed catalogs, blogs, and gardening books. But what are they exactly? And how do you use them?
The United States Department of Agriculture (USDA) have outlined zones on a hardiness map based on the lowest temperatures for each area. They areas are divided by temperatures, so a “zone” may be city-wide, county-wide, but there can also be several zones within those parameters which are numbered differently. The hardiness zone map is a tool that clues the gardener in on which plants will survive in your general area.
Photo by timo_w2s
In fact, if you live in the western states, we have so many different climates that Sunset has broken them down even further and has a zone guide specifically geared for western gardeners. This extra map has confused more than one new western gardener, I assure you. You’re told to “know your zone” on the USDA map and you find that you’re in zone 8, only to have a friend tell you that your garden is a solid 7.
You argue that you saw your zone on the map and they say counter that they did, as well. Both of you are probably right, you’re simply looking at two different maps. Many plants at garden centers here in California will actually have both zone numbers on there which can lead to more confusion when you don’t realize that your area may be assigned two numbers (one from each map).
In any case, when you’re at a garden center purchasing plants, you’ll notice that the plant has been labeled with a zone number that corresponds with the map. When the plant number is matched to the zone map, you’ll immediately know the lowest temperatures that a plant can tolerate without dying. Of course, it’s not necessary to match up plants sold locally because they purposefully bring in the plants that grow well in that area. But knowing your zone comes in handy for making online plant or seed purchases.
Photo by DeiselDemon
Remember that the zone map is a wonderful tool for choosing garden plants, but it’s a general guideline. The specific conditions of your growing space (or microclimate) can have a big impact on plants. The location of the plant in your yard and the sun exposure (north, south, east, or west), topography such as hills and valleys all play a role in how well your plant will grow in your yard or garden.
USDA Hardiness Zone Map
Below is a basic version of the USDA zone map will give you a solid beginning as far as where your garden’s climate stands. Usually, you’ll find this number formula on a color-coded map of the United States. If you’re in the western states, here are the Sunset Climate Zones.
- Zone 1: Below -50 degrees F
- Zone 2: -50°F — -40°F
- Zone 3: -40°F — -30°F
- Zone 4: -30°F — -20°F
- Zone 5: -20°F — -10°F
- Zone 6: -10°F — 0°F
- Zone 7: 10°F — 20°F
- Zone 8: 20°F — 30°F
- Zone 9: 30°F — 40°F
- Zone 10: 40°F — 50°F
- Zone 11: 50°F — 60°F
You’re right about confusion, because a zone 9 in California (warm, dry) is nothing like a zone 9 in South Florida (hot, tropical). There is now a Sunset Zone map for the entire U.S., and it’s much better than the USDA map or the Southern U.S., because it breaks it down into micro-climates, which is very important here in FL. Unfortunately, most easterners have not gotten used to using the Sunset zones. The entire USDA zone map has actually been rewritten twice, due to global warming, but Bush refused to let it be released because it would prove global warming, and evidently, Obama doesn’t think it’s important. The warmer zones are inching upward, according to data from the last 30 years, so if you’re in the bottom of zone 8, you may be able to push the ticket to zone 9. I just plant things, and if they die, I don’t plant them again. I have Zone Denial Disorder anyway. 🙂
Deborah,
I have zone denial, as well, LOL. That said, it’s one of those things where you want to “know the rules so you can be educated when you break them” sort of thing (just like writing). Because zones can be confusing, I don’t ever talk about my California Sunset zone when I write. I use the original USDA map. I’m sure the new map will slowly make its way out there — and then it’s going to be zone soup for a while, LOL!
I’m still marveling at a man on the Florida Gardenweb forum who swears St. Petersburg FL is in 10a, when zone 10 doesn’t even start until you cross the Peace River in Charlotte County, about 150 miles away. He swears, it though! He has BAD zone denial disorder. When he put up a greenhouse to protect all his plants during the winter, I told him now THAT is the difference between where you are and 10a. In 10a, we don’t have greenhouses, we have temporary hoop houses with no heat.
I’m totally in zone denial! No doubt about it. 🙂
By the way, Deborah — California is HOT, nor warm, LOL.
OK, here we go shameless plug and all I live in total zone denial here in So Cal and armed with Moo Poo Tea <|;-)