How to Grow Giant Tomatoes: 7 Proven Methods
Growing massive tomatoes is a fun gardening experiment, but it does take a bit of work. Whether you’re growing them for fun or competing with neighbors, there are proven methods that can help you grow the largest tomatoes possible. Gardening expert Madison Moulton lists the tricks you should try.
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Most gardeners focus on flavor and production when growing tomatoes. But if you have a competitive streak, you may have thought about trying to grow the biggest tomato possible. They may not be as popular as giant pumpkins, but they are just as fun to grow.
Giant tomatoes aren’t just regular tomatoes that somehow grew bigger than the others. They’re the result of careful variety selection, precise growing techniques, and strategic management that focuses entirely on maximizing fruit size rather than overall production. The same applies to growing giant anything.
The techniques for growing giants often contradict standard tomato advice. Instead of encouraging multiple fruits, you’ll be removing most of them. Rather than promoting overall plant health, you’ll be directing every bit of energy into developing just a few massive fruits.
Start with the Right Varieties
Standard tomato varieties top out around two pounds max, even under perfect conditions. True giants can exceed five pounds when grown properly. It all starts with which variety you choose.
‘Cherokee Purple’ and ‘Brandywine‘ can reach impressive sizes under the right conditions. If you’re not sure, look for any names that mention big. While it’s not the only factor involved, choosing a large variety to start over a tiny cherry tomato will make a big difference.
For serious giant growers, seek out specialty varieties known for winning in competition settings. Or even better, find a competition winner and ask for a few seeds. These varieties have been selected specifically for maximum fruit size.
Restrict Fruit Numbers
This is where giant tomato growing diverges most dramatically from normal practices. Instead of encouraging maximum production, remove most developing fruits to concentrate energy into just a few giants.
This feels wasteful, but it’s essential for directing all plant energy into developing those selected fruits. The same process applies to growing competition-worthy giant pumpkins. Remove all other flowers and small fruits ruthlessly throughout the growing season, keeping only the best-performing fruits to grow.
Select the best-positioned fruits for development. These are typically ones on the strongest branches with a good support structure. Remove fruits that develop on weak branches or in positions where they can’t be properly supported as they grow larger.
Also remove competing flower clusters before they even develop fruits. This prevents the plant from investing energy in fruits you’ll eventually remove anyway. The earlier you make these decisions, the more energy remains for your selected giants.
Boost Soil Nutrition
Giant tomatoes require soil nutrition levels that gardeners would often consider excessive for normal tomato production. Overfeeding is a growing risk after all. But massive fruits need enormous amounts of nutrients to reach their potential size.
Start with plenty of compost worked into the soil, possibly more than you would usually use. Add other organic matter where possible to create the richest soil you can. Giant tomatoes are heavy feeders that benefit from soil nutrition levels that might not match other crops.
Then, supplement with liquid fertilizers throughout the growing season. Feed weekly with balanced fertilizer during early growth, then switch to phosphorus and potassium emphasis once fruits begin developing.
Monitor soil pH carefully, too, if you really want to manage nutrients. Giant tomatoes perform best in slightly acidic conditions. This pH range optimizes nutrient availability for the heavy feeding these plants require.
Use Support
Most tomatoes need support of some kind. Unfortunately, standard tomato cages aren’t quite enough when you want giant fruits. Supporting plants grown to produce giant tomatoes requires materials that can handle it. The structure needs to support not just the plant but individual fruits that can weigh more than you might expect.
Individual fruit support is helpful as tomatoes approach giant size. Use a soft cloth to create slings that support developing fruits, as you would with vertical squash or melons, if they seem to be struggling. Attach these supports to the main cage structure rather than the plant stems.
Stake cages securely into the ground, especially in areas with high winds, as cages can topple during storms. If needed, use metal stakes for additional stability.
Plan support systems before planting rather than trying to amend inadequate structures later. Moving or modifying supports around established tomato plants risks damaging the root systems.
Water Management
Giant tomatoes are made possible with consistent (and high) moisture levels that never fluctuate dramatically. Any water stress during fruit development can limit final size or cause growth cracks that ruin prize fruits just as they are starting to reach their full size.
To take the stress out of watering and ensure you get giant tomatoes, install drip irrigation. This provides steady, consistent moisture without wetting foliage. Hand watering is often impractical for maintaining the consistent moisture levels giant tomatoes require, unless you’re at home all day or spend a lot of your free time in the garden.
Mulch heavily around plants to manage soil moisture fluctuations. Use about 4 inches of organic mulch to insulate soil and prevent rapid moisture loss during hot weather. Consistent soil moisture translates directly into consistent fruit growth.
Monitor soil moisture daily during peak fruit development. Giant tomatoes developing rapidly can use enormous amounts of water, which makes sense since they are mostly made up of water in the first place. Inadequate water during critical growth periods permanently limits final fruit size.
Strategic Pruning
Pruning of tomato plants is not always 100% necessary, depending on your goals. However, if your goal is a few giant tomatoes, pruning is essential.
Giant tomato plants require more aggressive pruning to direct energy into fruit development. Remove all suckers throughout the growing season as they pop up. These divert energy from main fruit development and create dense growth that can increase the risk of disease.
Choose a few strong stems rather than allowing unlimited branching. This structure will also better support giant fruit development later in the season. Remove lower leaves as fruits develop to improve air circulation and direct energy upward.
Prune the growing tips once the desired fruit number is set to prevent further vegetative growth. This forces all remaining plant energy into fruit enlargement rather than continued stem and leaf development.
Timing
Giant tomatoes take time to grow. They require a longer growing season than normal varieties to maximize size. Plan on 100-120 days from transplant to harvest for maximum size potential.
Start seeds indoors a little earlier than your regular batch of tomatoes to ensure adequate growing time. The extended growing season is essential for reaching maximum fruit size. If it’s too cold to transplant in your climate due to starting early, rather transplant into a slightly larger pot than plant in the ground early and risk cold damage.
Resist harvesting fruits too early, even if they seem large. Giant tomatoes can put on significant size during their final weeks of development. Harvesting at the first sign of color change sacrifices potential size for earlier harvest.
Protect plants from early frost to extend the growing season. Use row covers or other protection methods to keep plants growing through light frosts that would end normal tomato seasons.
