At Southern Exposure, our goal is to preserve and share open-pollinated and heirloom varieties that thrive in the Southeast and Mid-Atlantic. Naturally, this means that many of our varieties tolerate some heat and humidity. However, if you’re a grower in the Deep South, you know that summers there can bring intense conditions. Many regions in the southeastern states deal with high temperatures, high humidity, increased disease and pest pressure, and some drought. To grow in these conditions, you’ll need to select varieties that can withstand them. 

Look for the Especially Well-Suited to the Southeast Symbol

The sun symbol in our catalog and website listings indicates that a variety will thrive in conditions particular to the Southeast. While all our varieties are well-adapted to the mid-Atlantic, those varieties with the sun symbol are particularly well-suited to hot, humid summers. 

Crops that earn the sun symbol are those that reliably produce with good flavor in the Southeast’s unique conditions. Their exact characteristics vary with crop type. For example, Anuenue Batavian Lettuce earned the sun symbol because it germinates well at soil temperatures above 80°F and is bolt resistant while our Arkansas Traveler tomatoes earned the sun symbol because they are disease resistant and produced delicious tomatoes under high heat and drought when other varieties failed. 

On the website you can sort for crops that are especially well-suited to the southeast.

Cool-Weather Crops

For cool-season crops, we look for varieties that display more heat resistance than standard varieties. Note that they still won’t perform well during the height of summer in the south. You’ll need to get these varieties in early or late.

Folks in warm climates can also grow cool-weather crops during the off season. In the Deep South, try fall planting crops like cabbage, lettuce, kale, and radishes for winter production. In areas with some cold temperatures, you can use row cover to plant about two weeks early in the spring or keep plants going about two weeks longer in late fall.

Shade cloth can also help you grow cool-season crops later into the spring by offering them a respite from the intense sun. 

Brassicas

When labeling brassicas for the southeast, we choose heat resistant varieties that are slow to bolt and maintain good color, texture, and flavor in hot conditions. 

Greens & Lettuce

Varieties of greens and lettuce that thrive in the Southeast generally have a few specific characteristics. These varieties germinate well even in warm soil, are bolt-resistant, and resistant to tip burn. They may also be drought-tolerant.

Root Vegetables

Root vegetables that are ideal for the Southeast maintain their solid, crisp texture even in hot dry conditions, rather than becoming large and woody.

Warm-Weather Crops

When we select warm-weather crops, we’re looking at a few key factors like disease resistance, especially to fungal diseases, pest resistance, drought tolerance, and the ability to set fruit and maintain good flavor in high heat. 

Tomatoes

High heat and fungal diseases often affect tomato production in the Southeast. At high temperatures, tomatoes may abort their flowers and fail to set fruit. In high humidity, they are more likely to succumb to common fungal diseases like late blight, alternaria, and fusarium wilt.

When selecting tomatoes for the Southeast, we look for disease-resistant and heat-resistant varieties that maintain good production in challenging conditions.

Cucumbers  

Cucumbers are a warm-weather crop, but at high temperatures, they tend to drop their flowers and fail to set fruit. For the Southeast, we select varieties that hold their flowers at higher temperatures and produce reliably. 

Squash

Vine borers are the enemy of all southern squash lovers. When selecting varieties for the Southeast, we look for good resistance to vine borers, fungal diseases, and tolerance of high heat and humidity. 

Peppers

Peppers generally perform well in hot weather, but many fall prey to a common pest in the Southeast: root knot nematodes. Peppers that receive the sun symbol show good disease and pest resistance. 

Beans 

Beans are another warm-season crop that can fall prey to high heat, diseases, and nematodes in the Southeast. Our recommended bean varieties for the Southeast display resistance to these common issues. 

Many other traditional southern crops like okra, southern peas, and dent corn are also well-suited to the Southeast.

A Few of Our Favorite Heat Tolerant Crops

Malabar Spinach: This tropical vining plant is a great alternative to traditional spinach and will produce all summer even in high heat.

Seminole Pumpkins: A small butternut-like winter squash variety that thrives in hot, humid areas thanks to its excellent resistance to vine borers and Downey mildew. 

Whaley’s Favorite Cabbage Collards: This old-time variety forms loose heads with mild flavor. It’s a great cabbage alternative and makes excellent collard kraut. 

Carolina Wonder Bell Peppers: This is the best nematode-resistant bell pepper for home gardeners. It’s also less prone to developing fungus in the seed cavity than the classic California Wonder. 

Neptune Tomato: Developed at the University of Florida, this hardy variety is ideal for gardeners and market growers in hot, humid, rainy growing regions where it is difficult to grow tomatoes. It has excellent heat tolerance and is resistant to bacterial wilt that’s common in the Southeast and Florida.

As soon as you start gardening, you begin to see the earth beneath your feet in a whole new way. Soil is a surprisingly complex topic and the key to plant health. While you may not know everything there is to know about soil, getting a good grasp of the basics can help you create a more productive garden. Soil pH is one of the critical elements for gardeners to understand. 

What is Soil pH?

In simple terms, pH stands for the “power of hydrogen” or “potential of hydrogen” and refers to the concentration of hydrogen ions in the soil. As the concentration of hydrogen ions in soil increases, the pH decreases, so the soil is more acidic. Conversely, a low concentration of hydrogen ions in soil means it has a high or alkaline soil pH. 

The scale for pH ranges from 0 to 14, with 7 being neutral. The lower numbers are acidic, while the higher numbers are alkaline. Most plants prefer a slightly acidic to neutral pH between 6.0 and 7.0, but I’ll cover that in more depth below. 

Soil pH by Region

Just as there are various soil types like heavy clay and loam across the United States, there are regional variations in the pH of unamended soils. 

Many factors contribute to the pH of native soil. Rainfall leaches alkaline nutrients like calcium and magnesium from the soil, making areas with heavy rainfall more acidic. Organic matter decomposition also creates more acidic soil. Leaves and pine needles release organic acids as they break down. The bedrock also affects the soil. Basic rocks like basalt break down to form more alkaline soils, while acidic rocks like granite lower the pH and create more acidic soils.

In general, the eastern United States, including the Southeast, has acidic soils, though there are smaller regional variations. Due to its rainfall, forests, and bedrock, the Pacific Northwest also has mainly acidic soils. The Midwest and Great Lakes fall closer to neutral, while the western states  tend to have alkaline soil. 

Smaller, regional variations have become more common thanks to humans. We’re constantly moving and mixing soil. Soil moved for construction, development, agriculture, and any amendments will affect the soil pH you find on your property.

How to Test Soil pH

The best way to test your soil pH is to get a full soil test from your local agriculture extension office or agricultural college. Usually, they offer free or very affordable tests for residents. Most offer some recommendations or support in addition to your test results.

To find your county extension agency, try browsing the listings of Pick Your Own. They list contact information for county extension agencies across the United States.

You can also find at-home pH tests at many garden centers. These offer quick results but aren’t as reliable. They also usually lack any additional support or recommendations. 

For more information on how and when to take an accurate sample, visit our guide to taking a soil test.

Soil pH for Plants

As I mentioned above, most vegetable garden plants prefer a slightly acidic to neutral pH between 6.0 and 7.0, but it can vary widely depending on the plant and the type of soil that they’re adapted to. For example, most of the Southeast has acidic soil, so many of our native plants like azaleas, American elderberries, goldenrod, and rudbeckia tolerate or thrive in acidic soil. 

The University of Maryland Extension has a helpful chart for the ideal soil pH for vegetable crops, including the level at which you should apply lime. You’ll notice that a few vegetables like potatoes and carrots tolerate a bit more acidity than many of the others.

Keeping vegetables within their key pH range is essential for good production. If the pH is too high (alkaline) or too low (acidic), the soil particles bind too tightly to essential nutrients, preventing your plants from using them, which will lead to stunted growth, disease issues, and poor production. 

In acidic soil, phosphorus, potassium, sulfur, calcium, and magnesium become less available. Toxic levels of aluminum, manganese, and iron can build up, damaging roots. In alkaline soil, iron, manganese, zinc, copper, and boron become less available. 

How to Change Your Soil pH

No matter what pH your soil test indicates, you can amend your soil to be suitable for the crops you’re growing. 

If your soil is too alkaline, you’ll want to lower the pH to make it more acidic. Elemental sulfur is a common option that’s easy to find. Many other garden amendments will lower the pH more slowly over time, including peat moss, compost, and fertilizer. 

If you’re on the East Coast, it’s most likely that your soil is too acidic. The most common way to remedy this is to amend your garden with agricultural or dolomitic lime, both of which are made from ground limestone. Adding biochar or wood ashes from your wood stove or fireplace can also slowly help to raise your garden pH. 

Knowing how much to amend your soil can be tricky. Too much sulfur or lime can be as detrimental as too little. Getting recommendations from a soil laboratory based on your test is the best option. The Clemson University Soil Testing Laboratory also has a handy lime calculator you can use based on your test results.

If possible, amend your soil at least three weeks before planting. While you can amend closer to planting time without harming plants, it will take several weeks before you see changes in your soil pH.