The tomato is, for countless gardeners, the crop that started it all — the first thing they grew to eat, and the reason they kept gardening.
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The tomato is, for countless gardeners, the crop that started it all — the first thing they grew to eat, and the reason they kept gardening. There is a simple, powerful reason: a sun-warmed, home-grown tomato tastes of something that a supermarket tomato simply does not. Tomatoes are productive, rewarding, and well-suited to gardens, pots, growbags, and greenhouses alike. They are not difficult, but they are demanding in a particular way: they need warmth, sun, consistent watering, regular feeding, and — for the most popular kinds — some support and pruning. Master a handful of routines and the tomato repays you with armfuls of fruit all summer.
The tomato (Solanum lycopersicum) originated in western South America and was domesticated in Mexico and Central America, before being carried worldwide. It is a member of the nightshade family (Solanaceae) — the same family as the potato, pepper, aubergine, and the poisonous deadly nightshade — a relationship that explains why the leaves and stems of the tomato are toxic even though the ripe fruit is a beloved food. Its warm-climate origin explains its need for heat and sun and its complete intolerance of frost.
The tomato is a sprawling, soft-stemmed annual (in cultivation) with divided, strongly aromatic green leaves. There are two fundamentally important growth habits:
The yellow star-shaped flowers are followed by the fruit, which ranges from tiny cherry tomatoes to large beefsteaks, in red, yellow, orange, purple, green, and striped.
Full sun and warmth — tomatoes need a hot, sunny, sheltered spot (at least six to eight hours of sun). In cooler climates a greenhouse, polytunnel, or a warm sheltered wall greatly improves results.
Rich, fertile, well-drained soil generously improved with compost or well-rotted manure; or a good-quality potting compost or growbag for containers. Tomatoes are hungry plants.
Consistent, regular watering is the single most important tomato routine. Tomatoes need a steady supply of moisture; erratic watering — letting the plant dry out, then drenching it — is the direct cause of several classic problems, including blossom end rot (a dark sunken patch at the base of the fruit, linked to calcium uptake disrupted by irregular watering) and split, cracked fruit. Water deeply and regularly, aiming at the base of the plant, keeping the soil evenly moist; containers and growbags dry out fast and need frequent, often daily, watering in summer.
Once the first fruits have set, feed regularly (typically weekly) with a high-potassium fertilizer (a "tomato feed"), which promotes flowering and fruiting rather than leafy growth.
Knowing your type tells you whether to side-shoot or not.
Outdoors, wind and insects pollinate tomatoes; under cover, gently shaking the plants or tapping the flower trusses helps fruit set.
Tomatoes are frost-tender and grown as annuals. Sow indoors in early-to-mid spring and plant out only after all danger of frost has passed and the soil and air are warm; the plants are finished by the first autumn frost.
Tomatoes are easy from seed sown indoors in warmth in early spring; grow the seedlings on, harden them off, and plant out after frost — planting them deep (tomatoes can root from the buried stem). Or buy young plants. Choose varieties suited to your space and conditions (greenhouse vs outdoor, bush vs cordon, cherry vs beefsteak).
This requires a clear distinction. The ripe fruit of the tomato is a safe and nutritious food for humans. However, the leaves, stems, and unripe green fruit contain toxic compounds (including solanine and tomatine, typical of the nightshade family) and are considered toxic to cats, dogs, and horses, and not for human consumption — eating the foliage or large amounts of green plant material can cause drooling, vomiting, diarrhea, and lethargy in pets. So: enjoy the ripe fruit freely, but keep pets from grazing on the foliage, and do not eat the leaves, stems, or unripe fruit. (Green tomatoes are eaten cooked in some cuisines, but the raw foliage and green plant material should be treated as toxic.)
Pros
Cons
Not ideal for shady, cold, exposed gardens (without a greenhouse), low-effort gardeners unwilling to water and feed regularly, or homes where pets graze freely on plant foliage.
Why do my tomatoes have a dark, sunken patch on the bottom? That is blossom end rot. It is caused by disrupted calcium uptake in the fruit, and the most common underlying cause is irregular watering — letting the plant dry out and then drenching it. The cure is consistent, regular watering that keeps the soil evenly moist.
Why are my tomato fruits splitting and cracking? Splitting is caused by irregular watering — a sudden surge of water (from heavy watering or rain) after the plant has been dry causes the fruit to swell too fast and crack. Consistent, even watering prevents it.
What does "pinching out side-shoots" mean, and do I need to do it? It applies to indeterminate (cordon/vine) tomatoes. Side-shoots are the shoots that grow in the angle between the main stem and a leaf; pinching them out keeps the plant to one or a few main stems and directs energy into fruit. Determinate (bush) tomatoes do not need side-shooting — so identify your type first.
Are tomato plants poisonous to pets? The ripe fruit is safe to eat, but the leaves, stems, and unripe green fruit contain toxic compounds and are considered toxic to cats, dogs, and horses. Eating the foliage can cause drooling, vomiting, and lethargy in pets. Enjoy the ripe tomatoes, but keep pets from grazing on the plants.
Why does my tomato plant have lots of leaves but little fruit? Usually too much nitrogen, which drives leafy growth at the expense of fruit. Once fruit has begun to set, feed with a high-potassium "tomato feed" instead. Poor fruit set can also be caused by temperatures that are too cold or too hot, or by poor pollination.