The Who, What, When, Where, and Why's of a Planting Zone

The Who, What, When, Where, and Why's of a Planting Zone

What is Planting Zone?

Planting zones or growing zones are illustrated on a map known as the USDA Plant Hardiness Zone Map. The US Department of Agriculture divided out the map of the US in areas which range from planting zone 1A to planting zone 13B. These are areas which range in minimum temperatures from -60 degrees Fahrenheit to 70 degrees Fahrenheit.

This system was designed for the gardening and agricultural industry. It was a way for companies to demonstrate which plants would work best in which areas, based on climate. It is important information for professional landscapers, as well as farmers.

However, it carried over to backyard gardeners and made it much easier for everyone to figure out which plants work best in each’s garden.

The idea is to match up plants and the climates where they originated from, with other similar environments around the USDA map. By understanding what zone you’re located in, you can find out which plants will grow best in your area and which won’t.

Also, which perennials will work as true perennials, and which will have to be treated as annuals. Knowing which planting zone you are located in can impact your gardening success in tremendous ways.

What a Planting Zone is NOT

It’s common for people to look at the USDA Plant Hardiness Zone Map and assume it would be divided out by region. We commonly perceive certain states as sharing similar climate conditions.

That isn’t how it works. We’ll share more with you in the next section how the USDA Plant Hardiness Zone Map is determined. For now, understand you can’t decide which plant should be planted in your area based solely on the region you live.

It’s more accurate to use planting zones because it’s measured by the climate which can be different in areas in proximity to each other.

How to Find Your Planting Zone

You can find your planting zone with our interactive map above, which is based on the data from USDA Plant Hardiness Map of 2012. Here are the 3 ways to use the map, use whichever method you prefer:

  • Enter your ZIP code in the search bar and click enter.
  • Press the “Use My Location” button. Allow the tool to use GPS to determine your location, then the map will show your planting zone.
  • Use your mouse or touchscreen to drag and zoom the map and find your location, then click or tap the map.

How Does the Map Work?

The USDA Hardiness Zone Map was created by collecting data from news stations around the United States.

Once the data is in, the process starts with determining the average minimum annual temperature per area. Based on these averages, different USDA zones have been created.

1A is the coldest zone in the US which averages a minimum winter temperature of -60 degrees Fahrenheit. 13B is the warmest zone which averages a minimum temperature of 70 degrees Fahrenheit.

When deciding what to plant in each zone, the plant must be able to thrive in a climate with such low temperature.

For instance, if you’re planting in zone 9A, the plant must be able to survive a minimum temperature of 20 degrees Fahrenheit to be a perennial.

Otherwise, you need to plant it as an annual. If that’s the case, check you frost dates and get a time in the year when it would be safe to plant in your zone.

Here’s the complete temperature range for each zone, according to USDA:

Temp (F) Zone Temp (C)
-60 to -55 1a 51.1 to -48.3
-55 to -50 1b -48.3 to -45.6
-50 to -45 2a -45.6 to -42.8
-45 to -40 2b -42.8 to -40
-40 to -35 3a -40 to -37.2
-35 to -30 3b -37.2 to -34.4
-30 to -25 4a -34.4 to -31.7
-25 to -20 4b -31.7 to -28.9
-20 to -15 5a -28.9 to -26.1
-15 to -10 5b -26.1 to -23.3
-10 to -5 6a -23.3 to -20.6
-5 to 0 6b -20.6 to -17.8
0 to 5 7a -17.8 to 1515
5 to 10 7b -15 to 12.2
10 to 15 8a -12.2 to -9.4
15 to 20 8b -9.4 to -6.7
20 to 25 9a -6.7 to -3.9
25 to 30 9b -3.9 to -1.1
30 to 35 10a -1.1 to 1.7
35 to 40 10b 1.7 to 4.4
40 to 45 11a 4.4 to 7.2
45 to 50 11b 7.2 to 10
50 to 55 12a 10 to 12.8
55 to 60 12b 12.8 to 15.6
60 to 65 13a 15.6 to 18.3
65 to 70 13b 18.3 to 21.1

Why Planting Zones Matter

If you’ve ever put in the effort to start your plants from seeds, or you’ve shelled out the money to plant a garden from seedlings someone else has started, you understand why planting zones matter.

Planting a garden is an investment of both time and money. If you plant something at the wrong time for your zone, you’ve wasted time, money, and effort.

Once you know your zone, you know how which plant you can grow and how large of a time window you have for growing the plant.

For instance, it’s common for people in parts of Alaska only to have a three-month growing season. Whereas people in zone seven through ten can produce a variety of plants practically year-round.

If you’re unsure how to determine which plant grows in what zone and when, then use a planting schedule based on your area.

This will show you what months to start seeds indoors, when to plant them outdoors, and if they can be grown in your area a second time.

You can also read the packaging at nurseries which will read “Hardy up to zone ___” or “Will grow in _____ zone and below during _______ season.”

Planting zones are the beginning of growing a successful garden.

Other Factors Which Will Impact Your Garden

Planting zones are essential to your garden, but they aren’t the know-all-end-all. There are other pieces to the gardening puzzle.

It’s important to understand each piece because knowing your zone and planting at the proper time for your zone will not equate to success without these essential elements:

1. Soil Quality

Planting in quality soil is important. You should test for soil pH and make sure it’s at the proper level for the plants in your garden.

Also, be sure to amend your soil with compost and other organic matter to help make it fluffy and well-drained.

2. Water

Everything needs water. If it doesn’t have it, it’ll die. Pretty simple to understand, right? Well, there are a few more elements to understanding how to water your garden correctly.

The rule of thumb is to give your plants one inch of water per week. Be sure to apply the water in one or two deep watering sessions per week instead of four or five shallow watering sessions throughout the week.

3. Sunlight

As everything needs water, everything needs sunlight too. Be sure your garden is in a sunny location with well-draining soil.

It’s a good idea to place your garden where it’ll get at least six hours of sunlight per day. If this isn’t feasible on your property, consider container gardening where you can move your garden around to get adequate sunlight.

4. Regional Factors

Zones can vary in your region. Some states can have two or more zones in their state alone.

That leads to different temperatures and planting times, but they all have to face certain weather conditions common to their area.

For example, zone eight spreads from the east coast of the United States to the west coast. What one person in zone 8 may deal with on the east coast, someone on the west coast in zone 8 may not have to deal with.

Certain areas of zone 8 are much hotter than other areas. Some locations deal with hurricanes and tornadoes, while other locations don’t experience this as much.

Some small areas within the zone might also have microclimates that makes the general climate different to the surrounding areas. This mostly happens in heavy urban areas where buildings absorb the sun’s energy and radiate the heat to the air, which makes the temperature higher than the zone average.

If you live in an area where you know you will face extremely high temperatures or drought at some point in the gardening season, you could plan ahead by creating a hugelkultur garden. Understanding what weather threats are common in your region can help you better prepare your garden.

All of these factors can be considered and planned for to give your garden the greatest chance of success.

What’s the Next Step?

Now that you know what your planting zone is, the next step is to know what to do with that information.

1. Don’t Grow Certain Plants

Each plant has zone requirement. Corn, for example, can only be grown in zones four to eight. This means if you live outside these zones, you shouldn’t grow corns.

You can usually find the zone requirement on seed packets. And normally local stores wouldn’t sell seeds that can’t grow in the area.

It can be heartbreaking to know if you can’t grow you favorite vegetables, but most of the times it isn’t worth the headache to plant something outside of your planting zone. Unless you live near a zone border, in which case you might be able to grow plants outside your zone with high cold hardiness if you’re prepared to mulch heavily and willing to take the risk of extreme winter temperature.

2. Plant Annuals as Perennials

On the other hand, if you live in warm zones, you might be able to grow some annuals as perennials.

Kale is a vegetable that grows in all zones, but you can grow it as perennials if you live in zones 7 and up. Which is great if you want to have kale all year long.

Make sure to know which annuals can be planted as perennials in your zone because choosing to plant perennials will make your garden more productive.

3. Practice Alternative Growing Methods

Many people in colder locations use greenhouses to prolong their growing period.It is a great way to start seeds earlier and produce crops later.

Even if you don’t live in an extremely cold zone, you can still use a greenhouse to grow vegetables over the winter to keep the frost off of them.

You can also practice straw bale gardening to be able to plant earlier since you build the garden and soil each year.

4. Know Your Frost Dates

With the USDA map, you can find out what plants you can grow. Another piece of information you should know is when to grow it. Just because a plant can be planted in your zone, doesn’t mean you can grow it all year.

Use the frost dates finder to find out the average first and last frost date in your area.

5. Gardening Tips for Your Zone

If you learn gardening from the internet or books, check if the guide is zone-specific.

Be careful, most authors of gardening tutorials don’t realize if their tips can only be applied in some zones. In that case, they can’t tell you if the guide is zone-specific and it’s up to you to know whether you can use it or not.

Here at MorningChores, we specifically create guides and tips for each zone so you won’t make the same mistake:


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