Growing Heirloom Tomatoes in Southern Climates

Harvesting your own fruit and vegetables is one of the most rewarding parts of gardening. Many people opt for tomatoes because they are straightforward to grow, produce a large crop, and are easy to incorporate into a variety of meals. But the excessive heat and risk of blight can make growing heirloom tomatoes challenging in hot, Southern climates. Let’s examine how you can protect your plants and what varieties you might opt for to ensure success.

Growing Heirloom Tomatoes in the South

In general, growing tomatoes is fairly easy, and it should be possible in many different climates. However, hot or humid weather can make the process a bit more difficult. The two biggest problems you’ll face are excessive heat and blight, which is a disease that affects the growth of your plants. If you live in the South of the USA or another area of the world that is very warm in summer, you’ll have to protect your plants from these dangers.

Excessive Heat 

Average tomato plants that haven’t been bred to withstand very hot temperatures might not do very well in warm climates. They will start to wilt and drop blossoms, or the fruit may not be able to set even if there are enough pollinators around. With most plants, you might encounter this issue if the days are warmer than 90ºF and the night temperatures exceed 75ºF. Your tomatoes will stop producing fruit and simply focus on surviving the heat wave.

To minimize the problem, you will need to make sure that all the other conditions are optimal. Provide your plants with plenty of nitrogen so that they can develop healthy leaves but balance it out with phosphorus and potassium because they might otherwise produce many leaves with very few fruits. If you’ve had trouble with tomato plants in the past, you should opt for varieties that are resistant to the heat.


Many areas of the South are not only hot but also humid, which creates ideal conditions for a fungus called blight to infect your plants. There are two different kinds of this disease that can affect your tomatoes’ leaves, stems, and even their fruit. Early blight often occurs in the first half of the tomato-growing season, after heavy rainfall. If you catch it quickly, you can rip off affected leaves, but if the plant is already heavily affected, you might need a fungicide.

If your plants have late blight, the leaves will develop blue-gray spots that turn brown later on. When not treated, it can kill plants very quickly, so you’ll need to act and apply organic fungicides immediately. Copper spray is an organic blight killer that can be found at your local gardening center or online, and you can apply it once a week or after rain.

Preventing Problems 

As mentioned, you can buy plants that are resistant to excessive heat and can therefore produce tomatoes even if the temperatures exceed 90ºF. The same goes for blight, as there are certain varieties that won’t be so affected by the disease. Even if they contract it, they will still produce a good crop of tomatoes. Aside from buying the right plant, you can also prevent problems by being careful about not getting the leaves wet.

Always plant your tomatoes at least 24 inches apart so that air can move between the plants. You should also avoid watering them from the top and instead water the soil below them because you don’t get any moisture on the leaves that way, thus preventing the growth of blight. It’s important to remember that blight spores can live for a year, so rotating your crops can ensure that your new plants aren’t affected by the disease from the previous year.

The Best Heirloom Varieties for Southern Climates

If you’re quite new to gardening, you might have heard of the term heirloom tomatoes, but you might not know exactly what it means. In contrast to hybrid plants, this type of tomato isn’t intentionally cross-pollinated between two species but instead, the seeds are selected from the best parent plants in previous generations. Hybrid fruit generally all look the same, and they have the typical red hue and round shape, but heirloom fruit are all very individual.

Not only are they more natural, but they also generally taste better than their hybrid counterparts. Their DNA hasn’t been manipulated, and they have to be around for approximately 50 years to be labelled heirloom. While some are selected for flavor, acidic content, or size, others are particularly suited to southern climates. There are several varieties you could choose, depending on what results you’re hoping to achieve.

Arkansas Traveler

This plant originates in the Ozark Mountains and has been around for over 100 years. The fruit are medium-sized and mild, and they resist cracking. You should pick them when they start to develop a pink hue, as they will never become as red as hybrid tomatoes. On average, it should take about 75 days for your fruit to be ready. Arkansas Travelers are ideal for hot climates and droughts because they will keep producing fruit, even if the temperatures climb.

Dad’s Mug

Dad’s mug tomatoes also originate in the USA. They are great for making paste or canning because they have very few seeds and a thick skin. Similar to the Arkansas Traveler, they need to be planted in full sun and in well-drained, slightly acidic soil. While the optimal temperature for this variety is 80 to 85ºF, they should be able to grow in warmer climates, as well. If you’re starting them from seeds, your Dad’s mug tomatoes should be kept indoors at first.

San Marzano

Anyone looking for a very popular and high-yielding type of tomato can’t go wrong with the San Marzano variety. This historical plant was developed in 18th century Italy, so it has always grown in warmer and more Southern climates. You can either grow these from seed or buy some young plants from your local garden center. They should be readily available in many parts of the US.

San Marzano have a large root system, so you should plant them in big pots or straight into the ground. They need a minimum of 6-8 hours of direct sunlight, and the soil needs to drain well. Within 70-80 days, you will have a large harvest of long and thin tomatoes that have a strong and sweet taste.


Another very popular variety is Brandywine, which are well-known all around the US for their large size, ridges that make them look like a pumpkin, and the amazing taste. They have been around for many decades, and it is believed that the Amish first brought them to the country.

Although they can grow very well in southern climates, Brandywine tomatoes are a bit more care-intensive than some of the other varieties because they take longer to ripen and are therefore more susceptible to disease. If you’re a beginner gardener or have never grown tomatoes before, you might want to choose one of the other types first and then progress to these in later years.

Growing heirloom tomatoes is a rewarding process, but if you live in a Southern climate, you have to make sure your plants don’t suffer from excessive heat or diseases like blight. Selecting resistant varieties, being careful about the watering process, and rotating your crops can help to avoid issues.

seeds now ad

Posted by Amaral Farms

HI and thanks for visiting my blog. I guess I would say I have always been a gardener at heart. My parents gardened and I helped them from a young age. As an adult I took to the organic movement and began gardening using almost exclusively organic methods. My focus has shifted the last decade to add heirloom gardening to the mix. By no means an expert, I do enjoy it and spend at least a few hours a week dedicated to it. I hope you enjoy and gain some value from my blog.