Understanding Your Garden’s Unique Climate: Plant Zones, Frost Dates, and More!

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Hopefully, you know that growing a beautiful, thriving garden isn’t just about having a green thumb (or just blind luck) – it’s also about understanding your unique garden climate in the plant zone in which your plants are growing. Whether you’re dealing with frost, heat, drought, or heavy rainfall, each garden has its own unique set of challenges and opportunities. Don’t worry though, you don’t need to be a scientist or weather expert to grow a garden that will nourish you and your family!

Today, I’m going to break down with you some of the key things you need to know about your garden’s unique climate, from planting zones to frost dates and more. Fair warning, there is a lot of information here, but I don’t want you to get overwhelmed. Break it down piece by piece, and let me know if you have questions!

Whether you’re a seasoned gardener or just starting out, I hope this guide will help you make the most of your growing environment. Working with nature instead of making it bend to you, can help you create a beautiful, sustainable garden that thrives and flourishes!

What is your garden’s USDA plant hardiness zone?

The first thing I always do when learning about a growing climate is to check what USDA Plant Hardiness Zone it is in. The first thing you’ll see is a map of the whole United States with pretty rainbow colors over it. In order to find your zone, you can either enter your zip code into the search box on the map or click on “View Maps” at the top of the page for a static (less interactive) map.

Each color represents a hardiness zone from Zone 1a (in northern Alaska) to 13b (in Hawaii). The zones are based on the 30-year average minimum winter temperature and represent a 10-degree Fahrenheit deviation from zero degrees Fahrenheit. Each numbered zone is divided into “a” and “b” sections, each representing 5 degrees Fahrenheit. Zone 7a is considered “zero”, so any number smaller than 7 will be colder than the 30-year average minimum and any number higher than 7 will be a warmer growing climate that that same average.

So, why does it matter what gardening zone you are in? Quite honestly, if you’re only growing annuals (plants that grow for only one season), it doesn’t make much difference. One exception is that if you are shopping for garden seeds in-store and only have the seed packets to look at, some of them show the plant zones on the back as a guide for when you should start or plant the seeds. There are many things to take into consideration when choosing the best seeds for your garden, and your planting zone is only one of them.

When the USDA planting zones really come into play is for growing perennials (plants that are supposed to come back every year such as bushes, fruit trees, berries, some flowers, etc). Each variety of the type of perennial you have or want to grow will have a limit as to the cold it can take in the winter. For instance, if you try to grow a berry that was bred to grow in the south (able to withstand more heat and humidity) in North Dakota, it probably is going to get too cold over the winter and not survive.

What are your first and last average frost dates?

The next thing, and arguably for me, the most useful bit of information I like to find is my first and last frost dates. Dave’s Garden has a calculator for us to use, and it’s my favorite. It seems to be the most accurate for my location. All you need to do is enter your zip code and it gives you a couple of charts and other information. The first set is your location, and the charts below are surrounding zip codes. The results actually list your specific dates, but if you like to look at the charts, you’ll see “spring 32 degrees” and ” fall 32 degrees”. If you follow those rows over to the 50% column, those are the dates that you are looking for.

Your “last” frost date is the average date for the year after which you are unlikely to receive any more freezes. I am in zone 6a, and my average last frost date of the year is May 6th. That means that there is a pretty solid chance that we won’t receive any more freezes after that date.

On the flip side, your “first” frost date is the average date for the year after which you are highly likely to receive freezes. For me, that is October 7th. Do random cold snaps happen? Of course, but at least I have some idea of when I can plant.

When setting new plants out in the garden for the year, I tend to give them at least another week after my average last frost date. It seems that our property has a microclimate of its own, and tends to stay colder a bit longer than the surrounding areas in our zip code. You can read more on microclimates towards the end of this blog post.

The other information that we can glean from knowing our first and last frost dates is our growing season length. The great thing about the calculator I shared above is that it calculates that for you automatically! My frost-free growing season is around 154 days.

Why is that important? If you want to grow a variety of tomato that needs 95 days, but your average growing season only has 110 frost-free days, you either will harvest none or very little fruit from that plant. That plant needs several more weeks of the growing season to provide you with a good harvest.

You can alter your growing season at least a bit by the use of greenhouses, row covers, high tunnels, etc, but those only get you so much. It’s definitely important to have a good idea when your frost dates fall to avoid accidental loss of your garden plants.

How much rainfall will your garden receive? (Or not)

Let’s talk about rainfall. What type of area do you live in? Do you have dry drought-like conditions? Do you receive adequate rainfall? Do you receive an overabundance of rain each growing season? The amount of rainfall or moisture you receive on average plays a huge part in your gardening experience.

If you live in a hot dry climate as I do, your energy will be focused on conserving moisture in your garden. We can go weeks or even months without it raining, so I rely on irrigation for the most part in my gardens. I know, however, that water is a very precious commodity, so I try to conserve it as much as possible.

I only irrigate my gardens at night when it is cool and dark, that way it doesn’t evaporate as I”m trying to water and my plants have a chance to get a nice cool drink before the sun gets hot for the day. I also make use of heavy mulch in my garden. It is beneficial for many reasons, but mulch does a great job of keeping that moisture in the ground and keeping the ground cool. I use mainly straw mulch for my gardens as that is what I have most readily available.

For those of you that receive an overabundance of rain, you have the opposite problem! You need to find ways to keep water from standing in your garden and drowning your plants. Observing where water pools on your property is a good idea before starting an in-ground garden. Raised beds filled with well-draining soil are also a good option if you have standing water frequently.

There is a fine line between allowing excess water to run off and your soil drying out too much between rains, however, at least you won’t have to water very often, lol.

Figuring out how much rain you might receive in a growing season will help you decide where to put your garden, the type of soil and amendments you might need, as well as if you might want to try raised beds.

Is your garden sunny, shady, or a little of each?

As a homesteader, understanding the sun exposure of your garden is crucial for growing healthy and thriving plants. Depending on the location of your garden and the time of day, you may have areas that are full sun, partial shade, or full shade. Some plants thrive in full sun, while others prefer a bit of shade to protect them from intense heat. It’s important to know which plants will do well in each area of your garden so you can plan accordingly.

For example, if you have a large tree that shades one corner of your garden, you might consider planting shade-loving plants such as lettuce, kale, or spinach in that area. On the other hand, if you have a sunny spot that gets a lot of direct sunlight, you might opt for sun-loving plants such as tomatoes, peppers, or zucchini.

If you are unsure of the amount of sun your garden gets spend a little time doing some sun mapping. Sketch out your garden on graph paper (or plain). Choose a day that is mid-growing season so you have a good idea. (Ideally, you would do this a couple of times throughout the growing season) Go out every hour or every two hours and color in on your sketch what areas on receiving sun and shade and note the time. This will allow you to determine how many hours of full sun, shade, or partial shade areas of your garden receive and enable you to plant appropriately.

By taking the time to understand the sun exposure of your garden, you can maximize your chances of success and grow a diverse range of healthy and delicious crops.

What is your day length during the growing season?

When we talk about “day length” it is for a bit of a different reason than why we want to know if your garden is full sun or shade. Day length refers to the number of hours in a day between sunrise and sunset. Basically, how many hours the sun is shining, and is directly affected by your latitude.

Why does day length matter to your garden? There are 3 categories of plants when it comes to day length. Short day, day-neutral, and long day.

Short-day plants (like chrysanthemums and some onion varieties) may only flower or bulb if they receive 12 hours of daylight or less each day. Long-day plants (like some onion varieties and basil) will only grow appropriately if they receive more than 12 hours of sunlight in a day. Day-neutral varieties don’t really care about day length as long as they get their full sun or shade requirements. (Like tomatoes… they need 8 hours of sunlight a day, but don’t care if they get more.)

Try paying attention to the day length in your growing season, then look for varieties that match that day length. You might find improved yields and more blooms than you’ve ever had!

What high and low temperatures will your garden CLimate experience?

Temperature also plays a big part in the success of your garden. We’ve already talked about freeze dates and your USDA zone, but for this, I’m referring to your daily highs and lows in your garden.

Daily lows (outside of lows below freezing) play the biggest role when we’re talking about crops that really love warm weather. For instance, tomatoes and peppers really don’t like to dip below 50 °F. If they do that very often, their growth may be stunted. On the other hand, your cooler weather crops (like leafy greens and brassicas) will be perfectly happy with temperatures well below that. If you are forecasted to have a bit of cooler nights, you may want to look into row covers or walls of water to protect your warm-weather crops.

Daily high temperatures are my second biggest issue in the garden. (First being the wind, ugh!) We don’t get as hot as in some places, but it’s not uncommon for us to reach 100 °F frequently in the summer. Those temps coupled with the intensity of the sun and lack of rainfall basically roast my garden. Using tomatoes as an example again, when it gets above 90 °F consistently, tomatoes get stressed! They quit growing and their flowers fail to pollinate.

How do we combat the heat? Shade cloth is a huge help. Where I live, you can use up to 50% shade cloth over tomatoes and they will still grow great. Where you live, you may need a lower percentage or only shade in the heat of the day.

Heavy mulch is another way to help keep the ground and your garden cooler. Mulch holds moisture and the moist ground is much cooler than dry ground. Light-colored mulches also help to reflect the heat instead of absorbing it like bare dark dirt would. If it’s extra hot after you’ve set new plants out for the year, you may even need to go water them in the middle of the day.

Now, I know that goes against most advice that you will find about watering your garden, but as long as you keep the water low on the ground and keep it from splashing up on the leaves of the plant, you can cool off your garden a bit, give those new plants a drink, and avoid steaming them to death with wet leaves.

Make sure you take the time to monitor how hot and cold it gets in your garden during the garden season. This information will be very beneficial in helping your plants thrive when the weather gets a bit extreme.

Do you live in a windy area?

The wind is the enemy in my garden. Each year when it is time to plant my tomato and pepper plants in the garden, we end up getting weeks of relentless hot dry wind. It’s quite disheartening to listen to the wind howling, knowing that it is just wreaking havoc on my tender plants.

If you live in a windy climate, I’m sure you know what I’m talking about! So… what do we do about it? Natural or hand-built windbreaks are one option. You can plant a windbreak around your garden using trees and shrubs. Obviously, this isn’t a quick fix, but in a few years, it will be helpful. You could also build a windbreak using shade cloth or any type of solid or semi-solid materials. Pallets, corrugated metal, snow fences, and more are all good options for building a wall to keep the wind at bay.

Another option would be to use covers for each small plant. Milk jugs, coffee cans, 2-liter pop bottles, and 5-gallon buckets all work great. You simply cut the bottom off and settle them down in the dirt around your plants. Make sure they are anchored well if you have a big wind coming in. The downside to this option is that they can’t stay on after your plants start getting very big, so if you need a wind block for your entire growing season, you’ll need to use a more permanent option.

Wind can really hurt or set back your young plants. If you live in an area that receives frequent high winds, it may be worth building some sort of wind-break for your garden.

Don’t forget about your unique microclimate(s)!

While looking at the general area your garden is in is very useful, you also need to consider your specific microclimate(s). We can research all the things about the area you garden, but elements specific to your property may create small areas that behave differently than your general surroundings. We call these microclimates.

Our homestead sits on a creek bottom. As such, the microclimate of my gardens is colder than the surrounding area. My mother-in-law gardens just 2 miles away from me, and I am much more likely to receive a freeze if the temps dip down than she is.

My gardens are split into 3 locations across our property. Each one has its own little microclimate. One gets more shade, one more wind, etc. Even growing flowers, the ones in the front of my house (south side) get more intense sun and heat than the ones on the back side (north facing)

You may live in a place where microclimates aren’t much of a big deal, and that’s great. If you get more intense or extreme weather, pay attention to the growing conditions in each spot you plant. Choosing varieties better suited for each spot will help your garden thrive.

Conclusion

Whew! That was a lot of information. Understanding your garden’s unique climate is essential for successful gardening. By taking into account climate zones, frost dates, and other factors that affect plant growth, you can make good choices about what to plant and how to care for your garden. Whether you’re a seasoned gardener or just starting out, it’s important to evaluate and adapt to the specific conditions of your garden to maximize your chances of success.

Remember, there’s no one-size-fits-all approach to gardening. What works for one garden may not work for another, and that’s okay! The key is to observe, experiment, and learn from your successes and failures. With the right information and a willingness to try new things, you can create a thriving garden that brings you joy and satisfaction year after year.