Choose indeterminate varieties bred for size
The single biggest factor in growing giant tomatoes is starting with a variety that actually produces large fruit. Indeterminate tomatoes — the kind that keep growing and producing all season — are your best bet because they have more time to develop massive fruits. Determinate varieties (bush types that stop growing at a set height) tend to produce smaller, uniform tomatoes.
Varieties known for producing the largest fruit include Brandywine, Cherokee Purple, Mortgage Lifter, Beefsteak, Big Mama, and Sungold. Brandywine tomatoes regularly reach one pound or more per fruit. Cherokee Purple and Mortgage Lifter can hit similar weights. These aren't novelty varieties — they're established heirloom and hybrid lines that reliably produce oversized fruit if given proper conditions.
Buy seeds or seedlings from a reputable seed company or nursery. Starting from seed gives you more variety options, but buying established seedlings from a nursery gets you to harvest faster. Either way, confirm the variety name before you plant.
Key Takeaways
- Indeterminate tomato varieties like Brandywine, Cherokee Purple, and Mortgage Lifter are bred to produce fruit weighing one pound or more.
- Giant tomatoes need rich soil amended with compost, aged manure, or other organic matter worked in before planting.
- Removing lower leaves, pruning suckers, and limiting fruit per plant forces the plant to put energy into fewer, larger tomatoes instead of many small ones.
- Consistent watering — about one to two inches per week depending on rainfall and heat — prevents the fruit from cracking and splitting.
- Staking or caging is essential because the weight of large fruit will break unsupported branches.
Build rich soil before planting
Giant tomatoes are heavy feeders and need soil packed with nutrients and organic matter. Before planting, work compost, aged manure, or other organic material into the top eight to twelve inches of soil. A good target is to add two to four inches of compost and mix it thoroughly into the existing soil.
If you're planting in containers, use a high-quality potting mix (not garden soil) and add extra compost or aged manure to it. A five-gallon bucket is the minimum container size for a large tomato plant, but ten gallons or larger is better — bigger containers hold more moisture and nutrients, which large fruit demands.
Test your soil pH if you can. Tomatoes prefer slightly acidic soil, around 6.0 to 6.8 pH. If your soil is too alkaline, adding sulfur will lower the pH; if it's too acidic, adding lime will raise it. This step isn't mandatory, but it helps the plant absorb nutrients more efficiently.
Prune aggressively to concentrate growth into fewer fruits
The key to giant tomatoes is forcing the plant to put all its energy into a small number of fruits instead of spreading resources across dozens of smaller ones. This means pruning — removing parts of the plant that don't contribute to large fruit production.
Remove suckers (the shoots that grow between the main stem and branches) as soon as they appear. These are straightforward to spot: they're small shoots growing at a 45-degree angle where a branch meets the main stem. Pinch them off by hand or cut them with pruning shears. Removing suckers forces the plant to focus on the main branches and their fruit.
Once the plant is established and flowering, remove the lowest leaves (the ones closest to the ground) to improve air circulation and reduce disease. As fruit begins to set, thin the fruit on each branch. Leave only the largest, healthiest-looking tomato per cluster and remove the others. This sounds harsh, but it's what makes the remaining fruit grow large.
In late summer, pinch off new flower clusters that appear after your main crop has set. These late flowers won't have time to mature into full-sized fruit before frost, and they drain energy from the fruit already on the plant.
Water consistently and deeply
Inconsistent watering is one of the most common reasons giant tomatoes crack, split, or fail to reach their potential size. Aim for one to two inches of water per week, delivered slowly and deeply so the water reaches the root zone (at least six to eight inches down). In hot weather or sandy soil, you may need to water more frequently.
Water at the base of the plant, not on the leaves. Wet foliage invites fungal disease. Early morning is the best time to water because it gives any accidental leaf wetting time to dry before nightfall. If you use a soaker hose or drip irrigation, even better — these deliver water directly to the soil without wetting the leaves.
Mulch around the base of the plant with two to three inches of straw, wood chips, or compost. Mulch keeps the soil temperature stable, reduces water loss through evaporation, and prevents soil from splashing onto the lower leaves during heavy rain.
Support the weight with sturdy stakes or cages
A mature indeterminate tomato plant loaded with large fruit is heavy and top-heavy. Without support, branches will snap under the weight. Use sturdy stakes (at least six feet tall for indeterminate varieties) or heavy-duty cages designed for large plants.
Drive stakes into the ground at planting time, before the root system is established. Tie the main stem loosely to the stake with soft ties (cloth strips, old pantyhose, or commercial plant ties work well) every twelve to eighteen inches as the plant grows. Tie the knot around the stake, not around the stem, so the stem has room to expand.
If you use cages, choose ones at least five feet tall and made from sturdy wire or reinforced plastic. Flimsy cages collapse under the weight of large fruit. As the plant grows, weave branches through the cage openings to distribute the weight.
Feed regularly during the growing season
Even rich soil depletes nutrients as the plant grows and produces fruit. Feed every two to three weeks once the plant begins flowering. Use a balanced fertilizer (like 10-10-10) or one slightly higher in phosphorus and potassium (like 5-10-10) to encourage fruiting rather than excessive leaf growth.
Organic options include fish emulsion, compost tea, or diluted manure tea applied every two weeks. Synthetic options like tomato-specific fertilizers work quickly but require more frequent process. Follow the label directions — over-feeding can cause excessive foliage at the expense of fruit.
Calcium deficiency causes blossom-end rot (dark, sunken spots on the bottom of the fruit). If you see this, add crushed eggshells, gypsum, or a calcium supplement to the soil. Consistent watering also helps prevent this problem because calcium moves through the plant in water.
Harvest when fully colored but still slightly firm
Giant tomatoes take longer to ripen than smaller varieties. Pick them when they're fully colored (red, pink, or whatever color the variety is) but still slightly firm to the touch. If you wait until they're soft, they may split or crack during handling.
If frost threatens before your tomatoes are fully ripe, pick them at the breaker stage (when the first blush of color appears) and ripen them indoors on a windowsill or in a paper bag. They'll develop full flavor, though not quite as much as vine-ripened fruit.
Frequently Asked Questions
How big can tomatoes actually get?
The largest heirloom varieties regularly produce fruit weighing one to two pounds. Some specialty varieties have been grown to three pounds or more under ideal conditions, but one to one-and-a-half pounds is a realistic target for most home gardeners growing Brandywine, Cherokee Purple, or Mortgage Lifter.
Can I grow giant tomatoes in containers?
Yes, but use a large container — at least ten gallons, preferably larger. Fill it with high-quality potting mix amended with compost. Container plants dry out faster than in-ground plants, so you'll need to water more frequently. Everything else (pruning, feeding, support) remains the same.
What if my tomatoes are splitting or cracking?
Splitting happens when watering is inconsistent — the fruit absorbs water rapidly after a dry period and the skin can't expand fast enough. Water deeply and consistently every few days rather than giving the plant a heavy soaking once a week. Mulch also helps by keeping soil moisture more stable.
Do I need to remove all the leaves?
No. Remove only the lowest leaves (the bottom six to twelve inches) once the plant is established, and remove leaves that show disease. The plant needs leaves to photosynthesize and produce energy for fruit. Aggressive defoliation will actually reduce fruit size.
When should I stop pruning?
Stop removing suckers and pinching off new growth about six weeks before your first expected frost. At that point, let the plant focus on ripening the fruit already on it rather than producing new growth that won't mature before cold weather arrives.