Tomato spacing by variety, determinate vs indeterminate
Every SFG chart tells you tomatoes need one square foot per plant. That's not wrong. It's also not the whole truth.
I've grown every type of tomato in the catalog at some point. Determinates in buckets, indeterminates in raised beds, dwarfs in containers, cherries on trellises. The thing nobody tells you in the "1 per square foot" rule: indeterminate tomatoes are essentially different plants from determinates. Treating them the same is how you end up with a blighted jungle in August.
Here's what I've learned about spacing by actual variety.
Determinate vs indeterminate, the real difference
Determinate tomatoes grow to a fixed height (usually 3-4 feet), set their fruit all at once, and stop. They're compact, bushy, and self-supporting with a simple cage. Most paste tomatoes (Roma, San Marzano) and many commercial varieties (Celebrity, Mountain Fresh) are determinate.
Indeterminate tomatoes keep growing and setting fruit until frost kills them. Left alone, they'll reach 7-10 feet. They're vines, not bushes. They need aggressive pruning or a serious trellis. Most heirlooms (Brandywine, Cherokee Purple, Black Krim) and all "slicing" tomatoes are indeterminate.
A single indeterminate Brandywine can put out 40+ feet of vine over a season. Cramming one into a 12-inch square is asking for trouble.
Varieties I actually grow and their spacing
Black Krim (indeterminate, heirloom, 80 days)
My favorite tomato, period. Dark brick-red, smoky flavor, medium-large fruit. Single-stem prune on a 6-foot stake and it takes about 2 square feet of bed space. I plant at 1 per 4 squares (1 plant per 2x2 area) in SFG.
In 2022 I experimented with 1-per-square density for Black Krim. Got blight by July, lost half the harvest. Never again. 2 square feet per plant is the real minimum for Black Krim in a humid climate.
Cherokee Purple (indeterminate, heirloom, 80 days)
Similar to Black Krim but larger, pinker, and less smoky. Same spacing: 1 per 4 squares, 2 square feet minimum. Vines heavier than Krim; stake or trellis non-negotiable.
Brandywine (indeterminate, heirloom, 85 days)
The queen of heirloom tomatoes. Huge pink fruits, 1-2 pounds each. Massive vines. I give Brandywine 1 per 4 squares (2x2 area, 4 square feet) and still aggressively prune. Yield: 6-10 big tomatoes per plant over the season.
Sungold (indeterminate, F1 hybrid, 65 days)
Cherry tomato, orange-golden, absurdly sweet. The kids' favorite. Indeterminate and tall (6+ feet on a trellis) but the plant itself is lighter and less disease-prone than the big heirlooms. I plant at 1 per 2 squares (1 plant per 12x24 area). Yields hundreds of cherries per plant.
Roma (determinate, 75 days)
Classic paste tomato. Bush form, 3-foot height. Needs a modest cage, not a trellis. Full SFG density: 1 plant per square foot. I've fit 8 Romas in a 2x4 section without issue.
Determinates set fruit all at once. A row of 8 Romas will give you a 30-pound harvest over about 3 weeks in mid-August, perfect for canning sauce. That's the use case.
Celebrity (determinate hybrid, 70 days)
Reliable, disease-resistant, medium-fruit slicer. Great first tomato. 1 per square foot works fine. Standard tomato cage is adequate support. If you're starting your garden journey, plant four Celebrities in 4 square feet and you'll have sandwich tomatoes all summer.
San Marzano (indeterminate paste, 85 days)
The Italian paste tomato. Indeterminate despite being a paste, which confuses a lot of people. Vines aggressively. I space at 1 per 2 squares and prune to two stems. Makes the best sauce I've ever canned.
Glacier (determinate, 55 days)
Short-season cold-hardy variety. Good for Zone 4-5 or for early tomatoes in Zone 6. Small, compact bush. 1 per square foot, no trellis needed, sets fruit reliably even in cool weather.
A concrete 4x8 bed plan
Here's my 2024 tomato bed:
- 2 Black Krim (indeterminate) in squares 1-4 and 5-8 (a 2x2 block each)
- 2 Cherokee Purple in squares 9-12 and 13-16
- 4 Sungold cherries along the back wall, 1 per 12x24 area
- 4 Genovese basil at the base, one per tomato
Total: 8 tomato plants in 32 square feet = 1 plant per 4 sqft. Plus basil. Plus a trellis running the length of the back wall for the Sungolds.
Yield in 2024: about 140 pounds of fruit over the season. Enough for eating, for canning 12 quarts of sauce, for dehydrating 6 quart jars worth of sun-dried tomatoes, and for giving away to neighbors.
The single-stem prune
For indeterminate tomatoes, I prune to a single main stem. Remove every sucker (the shoots that grow between the main stem and a leaf branch) as it appears. The plant puts all its energy into fruit production on the main vine instead of splitting it across branches.
Yes, you get fewer total tomatoes this way. But the fruit is bigger, sets faster, and the plant stays compact enough to space at 1 per 2 or 1 per 4 squares without turning into a blighted mess.
Felco pruners are the tool. Sterilize between plants with a 10% bleach solution if you've had any disease issues. Prune in the morning when plants are dry, never when the leaves are wet.
Container tomatoes: spacing per gallon, not per square foot
Determinates in containers: minimum 5-gallon grow bag per plant. Celebrity, Roma, Bush Early Girl, all do fine in a 5-gallon. Dwarf varieties (Tiny Tim, Patio Princess) can handle 3-gallon.
Indeterminates in containers: 10-gallon minimum, 15 is better. Drip irrigation mandatory. Top-dress with compost every 4 weeks because container soil depletes fast.
The one-sentence rule
If it says "indeterminate" on the tag, plant it at 1 per 4 square feet minimum. If it says "determinate," 1 per square foot is fine. Add a quality trellis for indeterminates, a cage for determinates, basil at the base of both, and you're done.
Use the calculator with Mel's default 1-per-sqft density, then divide the result by 4 for indeterminates. Or just enter your actual bed dimensions and think in terms of the indeterminate-adjusted count.