Start with varieties bred to grow large

The fastest way to get big tomato plants is to choose varieties that naturally grow tall and produce heavy fruit. Indeterminate varieties — the kind that keep growing all season instead of stopping at a set size — will reach 6 to 10 feet or taller if you give them support. Beefsteak types like 'Brandywine', 'Cherokee Purple', and 'Mortgage Lifter' are bred to produce large individual fruits and tall plants. Cherry and patio varieties stay small by design, so they will not reach the size you want no matter what you do.

Check the seed packet or plant label for the words "indeterminate" or "vining." If it says "determinate" or "bush," that variety will stop growing at a fixed height, usually 3 to 4 feet. Indeterminate plants will grow as long as the season allows, which is why they need sturdy cages or stakes from the start.

Key Takeaways

  • Choose indeterminate varieties like Brandywine or Mortgage Lifter, which naturally grow 6 to 10 feet tall instead of stopping at a fixed size.
  • Plant in full sun (at least 6 to 8 hours daily) and space plants 24 to 36 inches apart so each one gets enough light and air circulation.
  • Feed every two weeks with a balanced fertilizer once flowers appear, and switch to lower-nitrogen formulas after the first fruit sets to encourage size over leaf growth.
  • Prune suckers (shoots that grow between the main stem and branches) on indeterminate plants to direct energy into fewer, larger fruits and a stronger main stem.
  • Water deeply and consistently — 1 to 2 inches per week — because irregular watering causes small fruit and splits, while steady moisture feeds larger growth.

Plant in full sun and space them properly

Tomato plants need at least 6 to 8 hours of direct sunlight daily to grow large and produce heavy fruit. Plants in partial shade will grow taller as they reach for light, but they will be thin and weak, and fruit will be smaller and slower to ripen. Choose a spot that gets morning sun through afternoon — afternoon shade in very hot climates (above 90°F regularly) can prevent sunscald, but morning sun is non-negotiable.

Space plants 24 to 36 inches apart, depending on the variety. Crowded plants compete for light and air, which slows growth and invites disease. If you are planting in rows, space rows 3 to 4 feet apart so you can walk between them and prune without damaging neighboring plants. Wider spacing means each plant gets more light and better air circulation around the leaves, which reduces fungal problems and lets the plant put energy into size instead of fighting disease.

Use rich soil and feed on a schedule

Tomatoes are heavy feeders, especially indeterminate varieties that grow all season. Before planting, work 2 to 3 inches of compost or aged manure into the top 8 to 10 inches of soil. This builds the nutrient base and improves water retention, which large plants need. If your soil is poor or clay-heavy, consider raised beds filled with a mix of compost, peat moss or coconut coir, and perlite — this gives roots room to spread and access to steady nutrients.

Once the plant flowers, feed every two weeks with a balanced fertilizer (roughly equal nitrogen, phosphorus, and potassium — look for numbers like 10-10-10 or 5-5-5). After the first fruit sets, switch to a lower-nitrogen formula (like 5-10-10) to push energy into fruit size rather than leaf growth. Too much nitrogen early on produces tall plants with lots of leaves but few flowers. Liquid fertilizers work faster than granular ones, so you will see results within days of feeding. Follow the label rate — more fertilizer does not mean bigger plants, and excess nitrogen can delay fruiting.

Prune suckers to focus growth on the main stem

On indeterminate plants, suckers are shoots that grow in the angle between the main stem and each branch. Left alone, they grow into full branches with their own flowers and fruit, which spreads the plant's energy across dozens of stems instead of concentrating it into fewer, larger fruits. Pinch off suckers when they are small — less than 2 inches long — by snapping them off with your fingers or cutting them with clean pruners.

Remove suckers every 7 to 10 days during the growing season. Focus on the lower half of the plant first, removing all suckers below the first fruit cluster. This opens up the base of the plant to air and light, reduces disease, and makes harvesting easier. On the upper half, you can leave a few suckers to develop into secondary stems, but remove most of them. The goal is a plant with one or two main stems instead of a tangled bush — this directs more nutrients to each fruit and makes the plant easier to support and manage.

Water deeply and consistently

Large tomato plants need steady moisture to grow big fruit. Aim for 1 to 2 inches of water per week, delivered in one or two deep waterings rather than daily sprinkles. Water at the soil level, not on the leaves — wet foliage invites fungal diseases like early blight and septoria leaf spot. A soaker hose or drip line laid at the base of each plant delivers water directly to the roots and keeps leaves dry.

Check soil moisture by pushing your finger 2 inches into the soil near the plant. If it feels dry, water deeply until water runs out the bottom of the pot or the soil is visibly wet 6 inches down. In hot weather, this may mean watering every 2 to 3 days. Inconsistent watering — wet one week, dry the next — causes blossom-end rot (a dark, sunken spot on the bottom of the fruit) and fruit cracks. Mulch around the base with 2 to 3 inches of straw or shredded leaves to keep soil temperature steady and reduce water loss.

Support the plant with sturdy stakes or cages

Indeterminate plants grow tall and heavy with fruit, so they need strong support from the moment you plant them. A standard tomato cage is often too small and will collapse under the weight of a large plant. Instead, use a sturdy stake — a 6 to 8-foot wooden post, bamboo pole, or metal rod — and tie the main stem loosely to it every 12 inches as the plant grows. Use soft ties like cloth strips or commercial plant tape so you do not cut into the stem.

Alternatively, build a Florida weave support system by running twine horizontally between stakes at the ends of the row, tying the twine around each plant's stem as it grows. This method supports multiple plants and is faster than individual stakes. Install support at planting time, not later — trying to stake a plant after it has grown tall and heavy risks breaking branches and damaging roots. A well-supported plant grows straighter, gets better light penetration, and is easier to prune and harvest.

Harvest fruit at the right stage to encourage more growth

Pick tomatoes when they are fully colored but still slightly firm — they will finish ripening off the vine and taste nearly as good as vine-ripened fruit. Removing ripe fruit signals the plant to keep flowering and setting new fruit, which extends the harvest and encourages continued growth. If you leave every tomato on the plant until it is soft, the plant slows flowering and focuses energy on ripening those fruits instead of making new ones.

In late summer, pinch off new flower clusters that appear after mid-August (or 6 to 8 weeks before your first frost date). The plant will not have time to ripen these fruits before cold arrives, and they drain energy from existing fruit. This forces the plant to focus on finishing the fruit already set, which means larger, sweeter tomatoes at the end of the season.

Frequently Asked Questions

Can I grow a big tomato plant in a container?

Yes, but the container must be large — at least 5 gallons, ideally 10 gallons or more. Bigger containers hold more soil and moisture, which large indeterminate plants need. Use quality potting mix (not garden soil), feed every two weeks, and water more often than in-ground plants because containers dry out faster. A 10-gallon pot can support a 6-foot plant if you stake it well and keep it fed.

What if my plant grows tall but produces few flowers?

Too much nitrogen or too much shade are the usual culprits. Switch to a lower-nitrogen fertilizer (higher phosphorus and potassium) and make sure the plant gets at least 6 to 8 hours of direct sun. Excess nitrogen pushes leaf growth at the expense of flowers. Also check that you are not overwatering — soggy soil reduces flowering. Let the soil dry slightly between waterings.

How tall will my tomato plant actually get?

Indeterminate varieties typically reach 6 to 10 feet in a long growing season (120+ days), but some can grow taller in warm climates with a long frost-free period. The plant will keep growing until frost kills it or you pinch off the growing tip in late summer. In short-season areas (less than 90 frost-free days), plants may only reach 4 to 6 feet before the season ends.

Should I remove leaves to help fruit ripen faster?

Remove only the lowest leaves (below the first fruit cluster) to improve air circulation and reduce disease. Leaves feed the plant through photosynthesis, so removing too many slows growth and ripening. Never strip the plant bare. A good rule: remove leaves only if they are diseased or if they are shading developing fruit on lower branches.

Can I use a tomato booster product to make plants bigger?

Products labeled as tomato boosters or fruit-setting sprays may help with flowering and early fruit set, but they are not a substitute for sun, water, and fertilizer. The basics — full sun, consistent watering, and regular feeding — will produce larger plants and more fruit than any spray. If you have those covered and still want to experiment, follow the label rate, but do not expect dramatic results.