Tomato

Tomato (Solanum lycopersicum) is the most-grown home garden crop in the United States, and for good reason: a single well-tended plant returns its seed cost many times over before the season ends. That said, “grow a tomato” covers an enormous range of decisions, and the ones you make early determine whether you end up with a 30-pound indeterminate sprawling over three feet of bed or a tidy determinate bush that delivers all its fruit in three weeks and asks for nothing else.

What you’re actually choosing between

Tomato cultivars divide first on growth habit. Determinate (bush) types stop growing at a genetically fixed height, set most of their fruit at once, and typically yield 10–15 lb per plant (Penn State Extension, Tomato Production, 2022). Good for canning because the harvest concentrates. Indeterminate types keep growing and flowering until frost kills them, and a well-managed plant in a long season can push 20–35 lb (Cornell Cooperative Extension, Home Vegetable Gardening, 2021). Good for fresh eating because you’re picking through the whole season.

Within those habits, fruit type shapes your ROI math. Cherry and grape types (‘Sungold,’ ‘Sweet 100’) sell at $3.00–$4.50/lb retail. Standard slicers average $1.78/lb according to USDA Economic Research Service 2023 retail price data. Paste varieties (Roma, San Marzano types) sit in between but are the right choice if you’re canning - higher solids ratio, fewer seeds, thicker walls.

The ROI case

A $3.50 seed packet contains 25–50 seeds. You’ll likely start 6–8 seeds and transplant 4–6 plants, putting your seed cost per plant around $0.25. At 10 lb per plant and $1.78/lb (USDA ERS, 2023 all-fresh-tomato retail average), one plant returns roughly $17.80 in grocery value. Indeterminate varieties in good conditions push that to $35–$60 per plant. The math favors tomatoes heavily - the real cost is time and the support infrastructure (stakes, cages, irrigation).

Growing requirements

Tomatoes grow as warm-season annuals in USDA hardiness zones 3–10. The limiting factor isn’t your winter minimum (they’re annuals) - it’s your frost-free window relative to your variety’s days to maturity. Zone 5 gardeners get roughly 150 frost-free days, which is enough for most varieties. Zone 3 growers need short-season varieties (60 days or under) and typically have to start transplants 8–10 weeks indoors before the last frost date.

You want soil temperature above 60°F before transplanting - not air temperature. A 70°F day with 50°F soil is still too cold; tomato roots stall below 60°F and stressed transplants invite disease. The ideal soil temp range is 65–75°F (University of California Cooperative Extension, Tomato Culture, ANR Publication 8017).

Soil pH should run 6.0–6.8. Below 6.0, manganese and aluminum become more available at potentially toxic levels, and phosphorus uptake suffers. Above 6.8, iron and manganese lock out. Most extension services converge on 6.2–6.8 as the practical sweet spot (Penn State Extension; OSU Extension, Soil Testing for Home Gardeners, HYG-1132).

Tomatoes are heavy nitrogen feeders early, then need that to taper off at flowering. Amend beds with 2–3 inches of compost before planting. Side-dress with a balanced fertilizer (10-10-10) at 4-week intervals during vegetative growth. Once flowers open, shift to a low-nitrogen, higher-phosphorus formula - excess nitrogen at fruit set pushes foliage at the expense of fruit.

Water 1–2 inches per week, delivered at the root zone rather than overhead. Drip tape or a soaker hose keeps foliage dry, which matters for disease management. Mulch 2–3 inches deep around plants to buffer soil moisture swings - those swings are the direct cause of blossom end rot.

What goes wrong

Early blight (Alternaria solani) starts as brown lesions with concentric rings on the lowest leaves and works its way up. It’s a fungus that overwinters in soil and on plant debris. Remove affected leaves promptly, avoid overhead irrigation, and space plants for airflow. Copper-based fungicides applied preventively help; they don’t reverse established infection. Rotate tomatoes out of infected beds for 2–3 years.

Late blight (Phytophthora infestans) is the more serious problem. This is the same oomycete that destroyed the Irish potato crop in the 1840s. In tomatoes it produces pale green, water-soaked lesions that spread fast in cool, wet conditions and can collapse a plant in days. There is no cure once it takes hold. Pull and bag affected plants; don’t compost them. Resistant cultivars like ‘Mountain Magic,’ ‘Defiant PhR,’ and ‘Legend’ are worth using if late blight is common in your region.

Hornworms (Manduca quinquemaculata, the tomato hornworm, and M. sexta, the tobacco hornworm) are 3–4 inch green caterpillars that are hard to spot against stems and can defoliate a plant quickly. Inspect plants twice a week and hand-pick. Bacillus thuringiensis var. kurstaki (Bt) applied to foliage kills larvae on contact once ingested. Hornworms with white rice-like protrusions on their backs are parasitized by braconid wasps - leave those alone.

Blossom end rot is not a pathogen. It’s a calcium deficiency in the developing fruit caused by inconsistent soil moisture disrupting calcium uptake. The bottom of the fruit turns brown and leathery. Fix it by watering consistently and mulching to prevent moisture swings - spraying calcium on leaves rarely corrects the problem because the issue is uptake, not soil calcium levels.

Aphids cluster on new growth and the undersides of leaves. A hard blast of water removes most colonies. Insecticidal soap is effective for heavier infestations; apply in the evening to avoid leaf scorch.

Harvest and storage

Pick when fully colored and the fruit gives slightly under gentle pressure. Tomatoes continue to ripen off the vine through ethylene gas production, so pulling slightly underripe fruit works fine. Do not refrigerate whole uncut tomatoes. Temperatures below 55°F break down the cell walls and volatile flavor compounds (Maul et al., Postharvest Biology and Technology, 2000). Store stem-side down on the counter, out of direct sun, and use within a week. Refrigerate only cut tomatoes, and use them within a day or two.

For preservation, paste varieties are most efficient for sauce and canning because of their lower water content. Cherry types dry well. Slicers can be canned whole or in chunks but require attention to safe acidity - always follow USDA-tested canning guidelines.

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Related crops: Basil, Cucumber

Related reading: Companion Planting Basics - what the evidence actually says about common pairings

Companion planting note: The tomato-basil pairing is one of the most cited in home gardening. Volatile compounds from basil (linalool, eugenol) have shown repellent effects on Spodoptera species and aphids in controlled laboratory studies (Hummelbrunner & Isman, Journal of Chemical Ecology, 2001). Field-scale evidence for measurable yield benefit is limited. Plant basil near tomatoes if you want fresh basil; the potential pest-deterrent effect is a bonus, not a guarantee.