Tomato

A tomato is a tender perennial from the Andean highlands of South America, grown as an annual nearly everywhere else. Frost-free, a single plant keeps growing, flowering and fruiting for years from a woody central stem; in a seasonal garden it rushes to finish its life cycle in one warm summer, which is why it works so hard to make fruit. The stem roots wherever it touches soil, the ferny foliage smells resinous when brushed, and the pale star-shaped flowers are self-fertile, so each blossom can set fruit with its own pollen.

Every tomato decision follows from one trait: growth habit. Determinate types, most bush and paste tomatoes, grow to a fixed size, flower over a short window and ripen a concentrated harvest two to three weeks later, then slowly quit. Indeterminate types, most cherries and beefsteaks, keep sending out shoots and flowering until frost ends them. Choose determinate for canning, containers and small spaces; choose indeterminate for tomatoes on the table from July to October, and plan on a tall cage or stake for each plant.

Tomatoes are tropical plants that act shocked in cold, and one frost ends the season. Set transplants out only after all danger of frost has passed and night temperatures reliably stay above 50°F, which is typically a week or two past your average last-frost date, because soil temperature matters more than air. A transplant checked at six inches by cold often stays a month behind a peer planted two weeks later, so it is better to wait than to rush. Roots stall below about 60°F soil, leaves flush purple, and early flowers simply drop.

Plant deeply. Bury the stem up to the top set of leaves, pinching off those it will pass beneath; tomato stems grow adventitious roots from any node underground, so a leggy six-inch transplant becomes a root system twice as deep as one set shallow. Water the hole as you fill it and firm the soil gently rather than packing it. Then give plants real air space, because crowded tomato foliage stays wet, invites disease and yields less per plant, not more.

Tomatoes want the hottest, sunniest spot you have. Six hours of direct sun is the working minimum and eight to ten is the goal; fruit from part-shade plants ripens slowly and tastes flat, because leaf area and sunlight are what make the sugars. Heat cuts both ways, though. Above roughly 95°F pollen goes sterile and flowering pauses, so in genuinely scorching climates an afternoon-shaded spot can out-produce full exposure during the hottest weeks.

Rich, well-drained, slightly acidic soil, around pH 6.2 to 6.8, keeps nutrients available and roots oxygenated. Work a few inches of compost into every bed and mulch after the soil warms to hold moisture even. Water is the habit worth training: one to two inches per week, deep and infrequent rather than sprinkled daily, and always at the base. Consistency matters more than volume, because it is the swing from bone-dry to soaked, not drought itself, that splits fruit and triggers blossom-end rot.

Support decides how a tomato grows all season. Cages suit bushy determinates but need the sturdy, heavy-wire kind and a ring of stakes if your site is windy. Single-stake or string trellising suits indeterminates: train one to three main stems and tie every few inches as they climb. Whatever the system, get support in place at planting; wrestling a mature plant onto a stake two months later snaps branches and shakes loose fruit.

Pruning is a choice, not a rule. On staked indeterminates, pinch off the suckers in the leaf axils below the fourth or fifth stem for earlier, larger fruit; on determinates and sprawled plants, leave them, because that extra foliage shades the fruit and bears more of it. Remove yellowing lower leaves once the first truss sets to keep splash-borne disease off. Feed at transplant with a balanced, low-first-number fertilizer, again when fruit first sizes, then lightly every two to three weeks; heavy nitrogen buys leaves and delays ripening.

Days to maturity on the seed packet count from transplant, not from seed, so treat them as a window: check the first cluster early. Pick at peak ripeness, when the fruit is fully colored and gives slightly under gentle thumb pressure and comes off with a simple upward twist of the wrist. Flavor compounds build in the final days on the vine, so vine-ripened really does taste better than refrigerated or windowsill fruit. Refrigeration below about 55°F dulls those compounds permanently, so store tomatoes at room temperature, stem-end down, and never on a sunny sill where they cook.

Two exceptions beat the vine rule. Bring mature-green fruit, glossy firm and just turning at the shoulders, in before forecast frost; it ripens fine on the counter in a paper bag. And pick colored fruit before big storms, because saturated roots split full skins. A late flush of green cherry clusters can be pulled whole at season's end and hung upside down in the shed to ripen slowly.

Most tomato trouble is physiological, not a pest you can see. A sunken, leathery dark patch on the blossom end is blossom-end rot, driven by erratic watering that starves the fruit of calcium even in calcium-rich soil; fix the rhythm, add mulch, and resist the reflex to lime heavily mid-season. Cracking radiates or rings around the shoulder after rain follows drought, and catfacing, the puckered scarred bottom on the first cluster, traces to cool weather at bloom. Both mostly self-correct once temperatures and moisture even out.

On the pest side, do not panic at the first hole. Tomato hornworms are large, slow and hand-picked; beneficial wasps leave white rice-like cocoons on their backs, so leave parasitized caterpillars be. Early blight's concentric-ring spots on lower leaves are managed by mulching to stop soil splash, stripping affected leaves and rotating away from nightshades for a year or two rather than by spraying.