Whether you are a new gardener or a seasoned expert, it’s essential to stay up-to-date with agricultural issues. For example, it’s important to know your gardening zone to successfully grow high-quality, healthy crops and plants and to familiarize yourself with USDA zones and their specific planting guidelines.
In today’s guide, we shall explore the USDA’s Zone 7A and Zone 7B planting guide so that you can make sure your garden flourishes during the growing season.
What is the USDA and What are USDA Zones?
Understanding the USDA’s planting guides and knowing what USDA Zones are is helpful before exploring Zones 7A and 7B. First, let’s explore what the USDA is.
What is the USDA?
The USDA, or the United States Department of Agriculture, is an agency considered to be the leading authority on food, agriculture, nutrition, rural development, and natural resources.
Furthermore, the USDA’s mission consists of two goals. On the one hand, the USDA strives to support the financial growth of the rural American farming industry. On the other hand, they endeavour to provide the world with a reliable, substantial source of food and to preserve America’s natural resources.
…And What Are USDA Zones?
Given the importance of agriculture production to the USDA’s ethos, the USDA has provided a plant hardiness zone map. This map serves as a collection of geographic areas in North America – eleven geographic areas, to be exact – that the USDA categorizes into zones.
Moreover, these zones represent the minimum average temperature of certain areas within North America.
Essentially, the lower the number of USDA plant hardiness zone, the lower the minimum temperatures are within that zone. For example:
- Each USDA zone represents ten degrees of temperature difference.
- Each USDA zone is divided into two subsets known as ‘A’ and ‘B.’ So, if you were to examine Zone 7, you’d encounter Zones 7A and 7B.
- Every subset within a USDA zone represents five degrees of temperature difference, representing the colder and warmer halves of a zone.
- Essentially, you can use the USDA zone map to determine how well your plants will prevail in cold temperatures within a zone.
By understanding the USDA’s plant hardiness zones, you can determine which plants, trees, and shrubs have the best chance of surviving the minimum winter temperature of your garden and landscape.
How to Use The USDA Plant Hardiness Zone Maps
Now that you know what the USDA is and what the USDA zones represent, it’s useful to know how to use the USDA Plant Hardiness Zone Maps.Using Zone 7 as an example, below we have explained how to use the USDA Plant Hardiness Zone Maps.
1. Familiarizing Yourself With The Map’s Color Usage
The first thing you see when you look at the Plant Hardiness Zone Map is a vivid assortment of colors:
- Red.
- Orange.
- Yellow.
- Green.
- Blue.
- Indigo.
- Violet.
Red zones indicate regions that have the warmest, average, and lowest winter temperatures. In contrast, violet zones mimic regions that have the coldest, average, and lowest winter temperatures.
This will enable you to immediately get a general idea of which plants will thrive in your location by seeing which color has been assigned to your region.
2. Allowing For Variances
The second step to using the USDA’s zone maps is to understand that the information provided is simply a culmination of the average lowest winter temperatures for a particular location. What’s more, these averages stem from data that spans over 30 years (between 1991 and 2020), meaning that it would be unwise to treat the map as a forecast for future climate conditions.
Plant hardiness zones don’t reflect the lowest temperature to have ever occurred in a given region. Therefore, if you want to grow plants that don’t have the best survival chances within your location, take into account that one bout of extreme climate change can cause them to perish.
Overall, it’s recommended that you only use plant hardiness zone maps as general gardening guidance.
3. Considering Important Environmental Factors
Now that you know how to use the USDA’s Plant Hardiness Zone Maps, consider other environmental factors that will affect your plant’s survival.
Humidity
When there is too much water vapor in your backyard, you may notice mold and bacteria growing on your plants. If you notice mold or bacteria on your plants, it is wise to act fast to increase their chances of survival. Scraping away the mold, using fresh potting soil, and washing your plants with fungicide will increase the likelihood that your plants will continue to thrive.
Soil Moisture
Different plants have individual requirements when it comes to soil moisture. What’s more, these requirements may vary as the seasons change. For instance, one unusually hot or dry autumn can affect your soil’s moisture levels in a critical way. Plants that would otherwise thrive in your zone may suffer the effects of unusual weather conditions and enter a state of dormancy caused by moisture stress.
Exposure
Some plants can withstand brief bouts of exposure to colder-than-normal temperatures, like dracaenas and chlorophytums. However, in contrast, prolonged exposure could lead to the plants perishing.
Light
Some plants, like astilbes, require partial exposure to sunlight to survive, while other plants, like geraniums, thrive in zones that provide full sunlight. If your zone experiences unpredictable weather conditions like too much sun in the winter, your plants could face stress factors due to rapid changes in their internal temperatures.
4. Finding The Right Plant Hardiness Zone
Simply visit the USDA’s Plant Hardiness Zone Map website and click on the ‘Map Downloads’ section, located in the upper left-hand side of the website.
Once on the site, you can choose to view or download three different types of zone maps: state/territory maps, national maps, or regional maps.
Simply choose which area of the map you wish to see and identify which zone you live in.
5. Preparing For The Zone Map’s Limitations
Understanding that no plant hardiness zoning system is perfect should be taken into account when tending to the plants in your own garden. For instance, you may have microclimates even in your own garden that will impact how your plants grow. Your entire backyard could be slightly warmer or cooler than the surrounding environment if it’s sheltered or more exposed to sunlight.
On the topic of warmer environments, it’s essential that you remember that the USDA’s Plant Hardiness Zone Map doesn’t reveal how much heat plants can tolerate. If you’re in a particularly hot climate, you may find little value in the USDA’s zone map as it doesn’t advise on a zone’s upper-temperature limits.
Where is USDA Zone 7?
Now that you know how to use the USDA’s Plant Hardiness Zone Map, you can use it to focus specifically on Zone 7.
Let’s start by listing the 28 states which fall into USDA Zone 7:
- Alabama.
- Alaska.
- Arizona.
- Arkansas.
- California.
- Colorado.
- Connecticut.
- Delaware.
- Georgia.
- Idaho.
- Maryland.
- Massachusetts.
- Mississippi.
- Missouri.
- Nevada.
- New Jersey.
- New Mexico.
- New York.
- North Carolina.
- Oklahoma.
- Oregon.
- Pennsylvania.
- Rhode Island.
- South Carolina.
- Tennessee.
- Texas.
- Utah.
- Washington.
A key thing to remember is that no state has just one zone. There can even be areas within a state that are classified as Zone 7B instead of Zone 7A.
For instance, in North Carolina, the mountain region falls into Zone 7A, while the Piedmont region falls into Zone 7B.
USDA Zone 7A and USDA Zone 7B: Choosing the Right Plants
Plants for Zone 7 can handle temperatures of 0°F to 10°F. However, it’s essential that you understand the differences between Zones 7A and 7B as they represent a more detailed temperature gradient.
For the sake of clarity, Zone 7A is a subzone that has a minimum average temperature of 0°F and 5°F. In contrast, Zone 7B is a subzone that has a minimum average temperature of 5°F to 10°F.
It’s also important to consider the frost dates within Zones 7A and 7B. The last frost date for Zone 7 typically occurs during the middle of April, while the first frost date generally occurs during the middle of October.
Overall, Zone 7 has a very forgiving climate with warm, damp summers that provide plenty of water and winters that don’t reach their minimum temperatures for very long. Therefore, Zone 7 can host a vast array of plants, fruit trees, and shrubs.
Below, we’ve listed some of the plants that thrive in both USDA Zone 7A and USDA Zone 7B:
- American Elm Trees.
- Shumard Oak Trees.
- Leyland Cypress Trees.
- Austrian Pine Trees.
- Sweet Chestnut Trees.
- Berries, including blueberries and raspberries.
- Fruit trees like apple trees and peach trees.
- Flowers like Azaleas and Hydrangeas.
- Vegetables like cucumbers, summer squash, and lettuce.
- Perennials like Bee Balm and Hellebore.
The Zone 7 Planting Schedule
If you’d like to grow a vegetable garden in Zone 7, you should adhere to Zone 7’s planting calendar so your vegetables have the best chance of survival.
Below, we’ve provided a visual representation of the Zone 7 planting schedule.
Source: https://veggieharvest.com/calendars/zone-7-vegetable-planting-calendar-schedule/
Please note that the Zone 7 planting schedule is not a strict rulebook for success in growing vegetables. Only treat this schedule as a rough guideline and consider the unique needs of your plants, along with the typical weather conditions in your region.
The USDA Zone 7B Planting Guide: Final Thoughts
Using the information in our article and the plant hardiness zone maps provided by the USDA, will guide you in making informed decisions.
Instead of guessing which plants may survive in your backyard, you can now grow a gorgeous garden, confident that your plants, crops, and blooms will thrive. Now that you’re ready to do some gardening, regularly consult the USDA Zone 7B planting guide and enjoy your garden.
For more advice and tips on all things gardening, don’t forget to check out our blog!
Frequently Asked Questions
Our most frequently asked questions relating to the USDA’s Zones 7A and 7B.
1. Which vegetables thrive in Zone 7?
Vegetables that thrive in cool seasons, like lettuce, spinach and peas, will thrive in Zone 7, especially when planted early in the year. Additionally, warm-season crops like tomatoes, cucumbers, eggplants, and peppers will also thrive in Zone 7, provided you plant after the last frost date.
2. Is the Zone 7 planting schedule relevant to outdoor hydroponic systems?
Simply put, the answer is yes. While hydroponics can provide greater control over your growing environment, outdoor systems can still be influenced by the seasonal temperature variations and frost dates of Zone 7. Ultimately, the Zone 7 planting schedule is relevant to outdoor hydroponic systems.
3. What grows best in Zone 7B?
We recommend that you grow the following plants in Zone 7B:
- Asters.
- Astilbes.
- Coneflowers.
- Hostas.
- Succulents.
- Tulips.
4. Is Nashville in Zone 7A?
In the latest USDA Plant Hardiness Zone Map, Nashville has moved from Zone 7A to Zone 7B.