To get you started, here's what you need to know about plant growth and different zones around the world. Once you understand the basics, head to the site and plug in your zip code to find your best matches.
- Mike DeRose, Mike DeRose is a professional gardener and the founder of The Pool Gardener.
How does the USDA planting zones map work?
The USDA planting zone map is based on the average, annual minimum winter temperature, and it is then divided into 10°F zones, with a range of 1-13 zones total.
USDA hardiness zones help gardeners understand which plants will survive in the area's extreme temperatures and which won’t. “Starting at zone 1 with the extreme minimum temperature set as low as -60°F, the ratings go all the way to 13 with an extreme minimum temperature of 70°F,” says gardener Dan Bailey, president of WikiLawn Austin Lawn Care.
Likewise, you don't want to plant anything that will wilt in temperatures higher than 70°F in Zone 13, Bailey says. Some plants also go through cycles of dormancy to survive extreme highs and lows in temperature, especially those lows.
“But many plants are not capable of this and will simply die if exposed to temperatures beyond what they can withstand so zones provide guidance when you're buying seeds so you know if your chosen crop can grow where you live,” Bailey says. Here’s a quick breakdown of zones.
A beginner's guide to USDA planting zones
Unfortunately, zones 1-4 are going to provide an unwelcome environment for most plants. “The vast majority of crops will not grow in this environment,” says Bailey. You can kind of just nix these zones for outdoor greenery, as most plants will not be able to thrive.
You can plant indoors though or use a greenhouse, and popular options include beans
Broccoli, cabbage, tomatoes, lettuce, radishes, spinach, mac apples, sweet peas, potatoes, kale, lettuce, herbs and tomatoes.
As you increase in zones, you can add in more options. Once you hit Zones 3 and 4, you are able to include carrots, root veggies (hearty, winter veggies), onions, other apples, pears, stone fruit like plums and apricots, delicate herbs such as parsley, garlic, horseradish, and peppermint, among others. Zone 4 includes eggplant, melon, pumpkin and some other pear varieties, along with the same plants from zones prior.
You can grow a few in these zones, yet more wintry plants that have hard exteriors and some toughness to them. “Planting in Zone 5 will require winter-hardy plants that can survive -20°F,” says Bailey, so the same wintry plants and veggies, as long as the climate is warm enough. These zones tend to be more mild and versatile, as long as you go by growing season and look for plants with a longer growing season in general.
These also similarly include peonies, succulents, tulips, lilies, bee balm, winter vegetables, hostas and more, and once you get to Zone 6, where summers are hotter, you can grow bush beans, butter lettuce, melons that have a longer season, winter squash, and indeterminate tomatoes, as well as other herbs and spices that can handle the heat but also require that boost, such as coriander, oregano and dill, for example.
If you plant in containers you can take plants indoors and outdoors to grow lots of different plants and keep them safe when there’s some wacky weather. Most winters are moderate and the summers are warm but not excessively hot. A large part of southern regions will be within Zone 8.
You can add in granny smith apples and some other herbs here too, like tarragon and sage, as well as some other varieties of stone fruit and persimmons, among other crops.
“Strawberries require a long growing season especially if grown from seed, 160-210 days, and the reason they are planted in the fall in Zone 7 or higher is because the temperatures stay warm enough through the fall/winter/spring that the above ground growth (the foliage) does not die off,” says deRose.
“Further north the foliage will die off in the winter, the roots will remain, but all the energy the plant spent growing the foliage would be wasted because it would die off before the strawberries produced,” deRose says.
You can grow perennial plants in these zones, as perennial plants live for more than two years and come back year after year. “Examples of perennial plants are blueberries, strawberries, fruit trees, pepper plants, lavender and lots of other flowers and most perennials will survive winter,” says gardening expert Mike deRose of The Pool Gardener.
Pepper plants include jalapeño, tabasco, habanero, poblano, and chile—an especially harsh winter can kill their root system and then they won't come back. “Prevent this by layering mulch on top of the soil to protect them,” deRose says. You can do this for plants in Zones 5 or 6 as well, if temperatures are drastically and unusually low, too.
The range in temperatures for Zone 9 is around 20°F to 30°F. From there, it basically goes up by 10°F until it reaches Zone 13, which is between 60°F and 70°F for average temperatures. In Zones 9 and 10, the results are pretty similar, as there isn’t much difference in climate range.
Zones 9 and 10 are in warmer regions where summers can get super hot, and the winters are pretty warm too, which could be an issue for some crops (think: California, Arizona, Texas, Florida and along the Gulf of Mexico coast).
You can plant a lot of veggies you’d cook with at home, such as asparagus, artichoke, beets, okra, aloe vera, arugula, bell peppers and basil, among some other air plants too. You can plant mint, avocado, olive, kiwi, citrus fruits, basil, thyme and chives, for example. You can add in a few more in Zone 10 that may not do well in 9, like ginger, peanuts and jicama.
With no frost days throughout the year, Zone 11 is one of the warmest in terms of hardiness zones and you can plant more fruits, like tropical fruits. The above crops apply, but summers are super hot, so some crops won’t do well, like pansies and spinach.
Growing herbs in Zone 11 is tricky and most won’t produce seeds due to the heat. You’d plant herbs as annuals during the cooler months. In this zone you can add in some others, like macadamia, lemongrass, and mango.
Your best bet is to plant during cooler months and incorporate shade (keep them indoors) and irrigation to fight the heat, since these climates are super hot and tropical. Plus, there is a late summer monsoon season, so use it to offer some heat reduction and plant during this time as well.
The best plants are both heat and drought tolerant and require just a short growing season, since the climate is so hot throughout the year. They are best fitting for the moisture levels. Some examples include bush beans, tropical almond, black pepper, eggplant, hot peppers, summer squash, and tomatoes, as well as some herbs, such as cilantro, sage, and rosemary.
How to match zone and plant survival rate
Bailey offers an example based on his zip code, which you’d find through search on the USDA map guide (in the search section where you enter your zip code). You can also match the zones to a letter to be more precise online as well.
“I live in an area [Austin, Texas] that's zoned for 8b, meaning it supports minimum temperatures of 15-20°F,” says Bailey. “Let's say I plant crops that are good in those temperatures, maybe even 10°F, then the winter storm that plummeted Texas into below-zero temperatures this year would have very likely disrupted all of my plants,” Bailey explains.
So, you’d want to plant crops that thrive in warmer climates and avoid those that may not do well in lower temperatures, since you can find some unpredictable weather here and there.
Here’s another example: “If we use the zip code 90210 we will see that we land in the zone 10b, which has an average minimal yearly temperature of 30°F to 35°F, so if we wanted to grow cacao we would need to figure out what temperatures it grows well in,” says deRose.
Cocoa can grow in the range of 65°F to 90°F (18–32°C). Temperatures below 50°F (10°C) may cause the plants to die though, and temperatures that are higher than 90°F (32°C) may also be too hot for the plants to grow well.
So, you can grow cocoa in zone 10, but you probably need to protect the plant during the coldest days out of the year. “When temperatures drop below 50°F try using row covers or a makeshift hotbox/greenhouse,” says deRose. “Or grow cacao ahead of time where it is done before the coldest months of the year."
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