What gardening zone am I in? Determining Planting Zones & Growing Zones

If you have some gardening experience, you have probably come across seed package labels with gardening zones indicated. What exactly do these zones mean, and which plants thrive in each zone? The USDA Plant Hardiness Zone interactive map was created to give gardeners an idea of the general climate conditions prevalent in their areas and, thus, the plants that might or might not survive in every zone. While the planting zone concept is not exactly foolproof, it is a great way to determine what to plant and what to avoid. This guide will help answer the beginner gardeners’ question, “What gardening zone am I in?”, by going over how you can determine your gardening zone and taking a brief look at the different zones.

What is a Gardening Zone?

A gardening zone [1] is an area on a gardening map that outlines the plants that can grow best in the area. Terms such as planting zone, growing zone, or plant hardiness zones are often used interchangeably to refer to the same thing. Essentially, such a zone helps a gardener identify the plants most likely to survive extreme conditions such as winter in their area. Knowing your gardening zones gives you a solid base for making planting decisions.

Plant hardiness refers to a plant’s ability to survive extreme conditions such as cold, heat, flooding, and drought. The exact science behind plant hardiness can be somewhat complicated and often involves genetics and adaptation. A plant’s ability to withstand adverse conditions often depends on its genetic buildup and adaptability. It is also worth noting that even plant parts can have different hardiness levels. For example, the extreme cold might kill a plant’s leaves but leave the roots intact.

The gardening zone map helps farmers avoid mistakes related to poor plant suitability. With modern gardening techniques, one can easily control aspects such as soil, nutrients, moisture, and sunlight. However, temperature variations can be quite tricky to control, which is why the gardening map exists. For reference, the USDA Zone Hardiness Map has 13 gardening zones, numbered 1 to 13. It is worth noting that when a plant is rated hardy enough for a particular zone, it can still thrive in zones with a higher rating. For example, a plant rated zone-4-hardy will still do well in zones five and six.

How to Tell What Gardening Zone You Are In

We have already established the essence of knowing your gardening zone. However, how exactly do you figure out your plant hardiness zone? Well, that is quite simple, actually. The USDA (United States Department of Agriculture) has an informative, interactive map that contains useful information regarding temperatures in the United States and Canada. This information is derived from the average annual low-temperature extremes for each area. To view the map and determine your zone, click here [2].

It is worth noting that the interactive map does not consider the peak temperatures of the areas covered. As you will quickly notice on the map, the growing zones get warmer towards the south of the continent. Areas such as Alaska are in the first growing zone and are quite cold, while the likes of Texas are in significantly warmer zones.

The gardening zone map [3] contains 13 distinct zones separated by a 10℉ range. The larger the number, such as 13, the higher the annual minimum temperatures. The 13 zones are further subdivided into a and b sections, separated by a 5℉ differential. By knowing the expected lowest temperature, you can easily choose plants that will thrive if the climate gets to such extremes. To use the map, simply point and click your location, and the relevant information will pop up. It is worth noting that a huge portion of the continental USA falls between zones four and eight.

Besides using the USDA map as a reference, you might also want to consider visiting your local garden center for additional information. Such centers have people with very specific knowledge regarding your locality that might be more accurate than the somewhat generalized USDA map. Such a center might also help you identify whether your farm lies in a microclimate whose temperatures significantly from those of the surrounding areas.

During the most recent USDA update, the 13 gardening zones moved slightly northward, pointing towards increased temperatures. However, your zone might temporarily move south, especially during very harsh winters. This further highlights the need to visit a local gardening center. Keep in mind that a small change involving a half-zone could very well let you farm plants that might otherwise have been too tender for your zone.

The interactive map mentioned above is accurate to about half a mile of your location which is precise enough for most people’s needs.

What If You Are in the Middle of Two Gardening Zones?

While not very likely, you might find yourself located between two gardening zones or two subdivisions of the same zone. In this case, your best option would be to visit your local agriculture or gardening center for additional information. Unlike the USDA map, the center will have extensive information regarding your locale, probably collected over several years.

It is also worth noting that you could find your home located in a microclimate with conditions slightly or significantly different from those of the rest of the locality. In this case, your local center will also have useful information. If you find yourself between zones four and five, for example, it is good to remember that plants rated zone-4-hardy will also perform well in zone five but not the other way round. In such a case, your best bet would be to plant zone-4- hardy plants.

What Are the Different Planting Zones?

Here is a brief look at the 13 planting zones according to the USDA.

Planting Zone One

The USDA Plant Hardiness zone one covers regions considered the coldest and is the lowest designation on the map. Areas in this zone have minimum temperatures averaging -50℉ to -60℉, making them extremely harsh for gardening. Much of the USDA gardening zone one is in Alaska. Only plants with extreme drought and cold resistance can survive the area’s harsh tundra environment.

Planting Zone Two

USDA gardening zone two is found partly in the continental USA and partly in Alaska. This area has average minimum temperatures ranging between -40℉ and -50℉. While slightly warmer than zone one, zone two is still far from ideal for gardening. Harsh drought conditions and extreme winds pose major challenges to farmers. However, it is possible to garden by choosing native plants and using modern farming techniques.

Planting Zone Three

The USDA zone three is found in high altitude areas, sections of northern USA, and Alaska. This zone has average minimum temperatures ranging between -30℉ and -40℉. Some of the challenges that gardeners face in zone three include extremely low moisture, extreme cold, and strong winds.

Planting Zone Four

The USDA planting zone four is found in high-elevated western mountains, northern USA, and parts of the Alaskan coast. Areas in this zone have average minimum temperatures ranging between -20℉ and -30℉. Zone four is slightly friendlier to gardeners than the lower zones but still poses challenges related to short growing seasons that could affect flower and vegetable blooming.

Planting Zone Five

This zone includes parts of New England, North Central USA, and some parts of the Alaskan coast. The zone has average minimum temperatures ranging between -10℉ and -20℉. The areas in zone five experience moderately cold winters and have relatively short growing seasons. However, farmers in this zone can use started plants to speed up the growth process during the short window.

Planting Zone Six

The USDA’s planting zone six covers much of the continental USA and is generally referred to as mild climate. This zone’s average minimum temperatures range between 0℉ to -10℉. This zone’s areas experience mildly hot summers and cold winters, making them ideal for growing a wide range of plants.

Planting Zone Seven

Zone seven touches about 15 states in the USA. Areas in this zone have slightly warmer winters compared to those of zone six and hotter summers. The average minimum yearly temperatures range between 0℉ and 10℉. Farmers in this zone have a wide range of plant options to choose from. Additionally, multiple gardening options work extremely well in this zone. These include open farms, greenhouses, nurseries, and indoor gardens.

Planting Zone Eight

The USDA planting zone eight covers a wide section of the southern continental USA all the way to the west coast states such as California. Average minimum temperatures in zone eight range between 10℉ and 20℉. This zone experiences mild winters and hot summers, resulting in a significantly long growing season favoring farmers.

Planting Zone Nine

Zone nine is widely considered an all-year-round gardening zone. This zone comprises parts of Florida, Texas, Arizona, California, and the Gulf of Mexico. Planting zone nine has hot summers and warm winters with average minimum temperatures ranging between 20℉ and 30℉. Gardeners in this zone can have active gardens all year round.

Planting Zone 10

Planting zone 10 is made up of sections of Hawaii, Southern Florida, and California. Average minimum temperatures in this zone range between 30℉ and 40℉. It is worth noting that gardeners in this zone barely experience freezing temperatures, even during winter. However, summer comes with extreme heat, a factor that poses some challenges to farmers.

Planting Zone 11

USDA planting zone 11 covers Puerto Rico, Florida Keys, and a few areas in the continental USA. Zone 11 is extremely warm, with average minimum temperatures ranging between 40℉ and 50℉. This zone does not have a single frost day throughout the year. However, farmers’ options are greatly limited by the searing heat that occurs in summer.

Planting Zones 12 and 13

These two zones are not found in any section of the continental United States. However, they cover parts of Puerto Rico and Hawaii. Areas in this zone are best suited for plants with high heat tolerance. The average minimum temperatures range between 50℉ and 70℉. It is common to find exotic fruits and tropical plants in planting zones 11 and 12.

Summary

While one might not overly think about their planting zone, it is essential for making gardening decisions. Determining your planting zone helps you avoid planting mistakes that might result in crop failure. By checking out the interactive map described earlier in this guide, you can easily figure out which zone you are in.

Citations

1. https://gilmour.com/planting-zones-hardiness-map
2. https://planthardiness.ars.usda.gov/PHZMWeb/
3. https://www.diynetwork.com/how-to/outdoors/gardening/how-to-determine-your-gardening-zone