How to extend your tomato growing season

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Find out how to extend your tomato growing season and get another big round of tomatoes before first frost using tomato suckers from your current plants!

Here on the outskirts of Greenville, SC in Agricultural Zone 7B, the summer growing season has already peaked and is starting its slow descent towards fall.

All of our cool weather seed trays are sown and we’re looking forward to all the yummy produce that comes with cooler weather: broccoli, cauliflower, kale, carrots, cabbage and more. However, that doesn’t mean we’re ready to give up on getting a bunch of warm-weather produce while we still can.

Brassicas in soil blocks - Tyrant Farms

Brassica seedlings in soil blocks

To accomplish this aim we have a few little tricks that help extend our summer growing season. If you love tomatoes as much as we do (and our ducks do), then you’ll enjoy having some simple tricks up your sleeve to help you get another big round of tomatoes out of your garden before the first frost of the year.

Tomato growing temperatures – how cold is too cold for tomato fruit set? 

As long as your day and nighttime temperatures stay above 55 degrees, you can continue to get fruit set from most tomato varieties. There are also some tomato varieties that are much more cold tolerant and can continue to set fruit down into the upper 30s! 

These exceptionally cold tolerant tomato varieties tend to be heirlooms bred for short/cool summers in the far north. Examples include: 

  • ‘Glacier’ from Sweden,
  • ‘Stupice’ from Czechoslovakia, and
  • ‘Siberia’ from Russia.    

However, by midsummer, most tomato plants are well past their prime, having been drained of energy from fruit production or succumbed to various tomato diseases (late blight, fusarium wilt, etc.) 

Paul Robeson Tomato atop an Atlantic Giant Pumpkin - Tyrant Farms

‘Paul Robeson’ heirloom tomato taking a nap atop an ‘Atlantic Giant’ pumpkin. 

What are “tomato suckers”?   

The term “tomato sucker” refers to the new growth s that emerges from the joint between a primary stem and branch on a tomato plant. 

Even though most of our tomato plants are well past peak production, many of them continue to grow healthy suckers.

What's a tomato sucker? Tomato suckers

Tomato suckers.

Many people recommend keeping your tomato suckers trimmed off throughout the growing season to get larger fruit and healthier plants. However, we grow way too many tomato plants to keep all of our suckers cut, so we don’t bother to remove them.

We haven’t noticed any difference in our plants’ health, yields or fruit size either way, and we like not having to spend hours each week suckering all of our tomato plants.

Tomato suckers can form new tomato plants? 

Tomato Suckers - Tyrant Farms

Some freshly cut tomato suckers that will be used to grow new tomato plants at Tyrant Farms. 

As you may know, tomato plants root very easily. The “fuzzy” white texture you see on their stem surface are actually adventitious roots, that can actually become new soil roots.

Each year between mid-July and mid-August, we cut off suckers from some of our favorite tomato varieties and grow a last batch of healthy new plants that yield an abundance of late-season fruit.

Step by step: How to extend your tomato growing season by growing suckers

Step 1: Remove suckers from old, but otherwise healthy tomato plants. 

Cut off a few healthy suckers from some of your favorite tomato plants that are already past their prime, but not dying from disease. Use suckers that are at least 4-5″ long and already have a couple of healthy leaves/branches on them.

Plop them in a glass of water to keep them wet before the next step. Rooting Tomato Suckers- Tyrant Farms

Consider sanitizing your pruners between plants to prevent spreading disease. (The same reason surgeons wash their hands between patients.)

Trim all but the very top leaves/growth tip on the sucker. If the suckers are large enough to already have flowers on them, pinch off the flowers so that the new plant can put its energy into root growth rather than trying to set fruit.

Cutting the first few leaves off the tomato sucker. - Tyrant Farms

Cutting the first few leaves off the tomato sucker.

A completely trimmed tomato sucker just before planting - Tyrant Farms

A completely trimmed tomato sucker ready for the next step in the rooting process.

Step 2: Dip tomato sucker base in rooting hormone.  

Dip the stems of your suckers in rooting hormone. Because tomatoes root so readily, this step is optional, but will yield better results. 

Dipping the tomato sucker in rooting hormone. - Tyrant Farms

Dipping the tomato sucker in rooting hormone.

Step 3: Pot up your tomato suckers. 

Put the tomato sucker in a small seedling pot filled with quality seed starting mix or potting soil. Bury the stem up to the first leaves.

Remember, the adventitious roots on the stem we mentioned earlier? Yes, those will all turn into new roots. The more roots, the healthier the plant will be.

Use a small bamboo skewer to help make the hole and guide the plant in. - Tyrant Farms

Use a small bamboo skewer to help make the hole and guide the plant in.

Keep the new plants moist and in a part-sun location – ideally a few hours of morning sun and afternoon shade. Mist or water daily as-needed to keep the soil damp or if the plant looks limp.

Step 4: Harden off & plant in the ground.

After about 7-10 days, your suckers should have established new roots. You’ll notice its vigor increase and healthy new leaves start forming once the new roots have started forming.

Allow your new tomato plants a few days to harden off to full sun again. Generally, we follow this schedule for hardening newly rooted plants:

  • Days 1-2: 2-4 hours full sun;
  • Days 3-4: 4-6 hours full sun;  
  • Day 4-6: 6-8+ hours full sun.

Keep your eye on your plants for signs of stress. If they look limp, it’s either heat stress or lack of water. If the leaves start to brown, they’re getting sunburned.

Finally, once your tomato plants are hardened off, find a good, sunny, tomato-friendly location and get them in the ground as soon as possible! 

Step 5: Harvest. 

Where we live in South Carolina, we often don’t get our first frost until late October or November, so we can get a lot more tomatoes before fall sets in. Select a smaller-fruited tomato variety if you’re worried about not having enough time to get a good harvest before first frost (larger-fruited tomatoes take longer to ripen).

If you want to push the season even further, consider using frost blankets or old bed sheets on cool/cold nights to keep your tomatoes going beyond their normal growing season.  

Or if you see a frost about to hit before your large tomatoes are fully ripe, you can always make a big batch of green tomato marmalade, a delicious treat made from unripe green tomatoes that we’ve fallen in love with over the years.

The tomato season-extension methods in this article don’t require any seeds and produce new, robust plants far faster than growing them from seed. We hope this info helps you get a big late season tomato harvest this year! 


Other tomato articles you may enjoy: 

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