Tomatoes

Choose a growth habit

Names can mislead: Clemson lists 'Early Girl' as indeterminate, while 'Bush Early Girl' stays under 3 feet. Its table marks 'Celebrity' and 'Roma' determinate and 'Better Boy', 'Sun Gold' and 'Brandywine' indeterminate.

Spacing in beds and containers

Two Iowa State pages differ slightly on determinate and caged spacing. In a raised bed without row aisles the in-row figure counts, so a staked plant needs roughly a 2 × 2 ft patch; compare square foot gardening spacing.

For pots, University of Maryland Extension gives one full-size tomato 8–10 gallons at 12–16 inches deep and dwarf tomatoes 4–6 gallons at 8–12 inches; Clemson accepts a 14- to 20-inch container or a drilled five-gallon bucket for compact cultivars. See growing tomatoes in containers.

Stakes, cages and weaves

• Single stake: Clemson uses 6-ft wooden stakes, 1½–2 in wide, driven 1 ft deep and 4–6 in from the plant soon after transplanting, with ties about every 10 in; UGA gives the same depth, distance and tie spacing for 1-in-square stakes. Virginia Cooperative Extension calls for 6-ft stakes driven 2 ft deep for determinate types and 8-ft stakes for indeterminate ones.
• Pruning: Clemson trains staked plants to one or two stems, removing suckers weekly; caged plants are pruned once, to three or four stems.
• Weave: Clemson's Florida weave puts 6-ft stakes every other plant and runs twine along both sides, adding a line about every 10 in. Virginia starts the first line 10 in above the ground once plants reach 12 in.
• Cage: Clemson asks for at least 6 in between wires; Virginia says 4-in mesh lets a hand through for picking and suggests anchoring the cage to one or two stakes.

Sources split on two points. UMN says determinate types need no staking, while Clemson and Virginia give stake specifications that cover them. And Clemson's own fact sheet lists cages as an option, but its cultural-management article prefers stakes, trellises or the weave because cages can crowd growth and slow leaf drying.

Timing from your frost date

1. Look up your average last spring frost date (see frost dates explained).
2. Start seed indoors 6–8 weeks before the last frost (Clemson, UNH) or 5–6 weeks before your outdoor planting date (UMN, Iowa State); UGA gives 4–7 weeks.
3. Harden plants off for about a week (Clemson, UGA) or gradually over one to two weeks (UMN).
4. Transplant once frost danger has passed and the soil has warmed (UMN): 1–2 weeks after the last frost per UNH, typically 2+ weeks per Colorado State, which classes tomatoes as "very tender" and lists 50°F as the minimum soil temperature, measured 4 in deep at 8 a.m.
5. Plant deep. Clemson buries the stem so only two or three sets of true leaves show and lays leggy plants sideways; UMN digs a 3- to 4-in trench and buries the stem to just below the lowest remaining leaves.

Late limits vary by region: Iowa State gives June 20 as the last practical planting date in Iowa, while Clemson lists a July 1–15 fall planting window for South Carolina's Coastal Plain. The planting calendar turns your frost date into dates.

Water and mulch

UMN aims for 1 inch of rain or irrigation a week; an inch wets sandy soil about 10 inches deep and clay about 6. Iowa State also gives about 1 inch, applied to the soil in the morning. UGA gives 1–2 inches in one or two deep soakings, through drip or soaker hoses. Maryland puts it per plant: a mature tomato may need 2–3 gallons a week. Containers may need daily water in midsummer (Clemson).

Mulch depth runs from 2–3 inches (Iowa State, UGA) to 3–4 inches of weed-free straw or herbicide-free clippings (UMN). UMN notes black plastic warms the soil; Iowa State calls plastic mulch not cost-effective for home gardeners.

Common pests and disorders

Clemson separates the two hornworms by horn and markings: the tomato hornworm has a straight black horn and eight V-shaped marks per side, the tobacco hornworm a curved red horn and seven diagonal white stripes.

Blossom end rot: calcium or water?

Sources agree it involves low calcium in the developing fruit and uneven water, but weigh the fixes differently. NMSU says drought stress, not soil calcium, is usually the cause in New Mexico. Maryland and UGA recommend correcting pH, supplying calcium (gypsum; UGA also dolomitic limestone) and avoiding excess nitrogen, and both treat calcium sprays as short-term at best. A soil test, which Clemson and UMN recommend before fertilizing, shows whether calcium or pH is actually low.

Where sources disagree

This page gives no pesticide rates. UC IPM lists Bt or spinosad for small hornworms, and Clemson's pest fact sheet lists insecticides for South Carolina conditions with the instruction to use them only according to the label. If you use any product, follow the label exactly and check your state extension service's current guidance.

Small-space checklist

• Six or more hours of sun, and a spot where tomato-family crops have not grown recently.
• Compact determinate or "patio" cultivar for pots; label height checked.
• About 2 × 2 ft per staked plant in a bed, or 8–10 gallons per full-size plant in a pot.
• Stake, cage or weave in place on planting day.
• Planted after your last frost date, buried deep.
• Mulched; watered at the soil, about an inch a week in beds.
• Lower leaves checked weekly for spots and plants checked for hornworm droppings.