Tomatoes, Peppers, and Nightshades: A Complete Growing Guide

Tomatoes, peppers, eggplants, and their relatives in the nightshade family (Solanaceae) are among the most popular and rewarding warm-season vegetables. They reward good growing conditions with generous harvests but require attention to achieve their full potential.

Variety selection fundamentally shapes your success. For tomatoes, determine how you will use them: cherry tomatoes (sungold, sweet million, black cherry) produce prolifically over a long season and require less support. Slicing tomatoes (beefsteak, brandywine, celebrity) produce fewer but larger fruits ideal for sandwiches. Paste tomatoes (san marzano, amish paste, roma) contain less water, making them best for sauces and canning. Also choose between determinate varieties (produce all at once, stay compact, better for containers and canning) and indeterminate varieties (continue producing until frost, require staking, typically better fresh eating).

Starting from seed indoors gives earlier harvests and access to hundreds of varieties not available as transplants. Sow tomato seeds 6-8 weeks before the last frost date; pepper seeds 8-10 weeks before, as peppers germinate and grow more slowly. Use a sterile seed-starting mix, maintain soil temperature at 21-27 degrees C for germination (using a seedling heat mat), and provide 14-16 hours of artificial light or a very bright south window once seedlings emerge.

Transplanting timing is critical for warm-season crops. Nightshades thrive only when soil temperature consistently exceeds 15 degrees C at night and air temperatures stay above 10 degrees C. Cold-shocked transplants (planted too early) often stall completely, allowing later-planted seedlings to catch and surpass them. Harden off transplants by gradually acclimating them to outdoor conditions over 7-10 days before planting.

Deep planting benefits tomatoes uniquely among vegetables — they can form roots along any buried portion of stem. Plant tomato transplants 15-20 cm deeper than their nursery pot level, removing lower leaves. This develops a deeper, more extensive root system that better withstands drought and anchors tall plants.

Staking and support is essential for most tomato varieties. Indeterminate varieties can reach 2 metres or more and require substantial support: heavy-gauge cages, wooden stakes, or trellis systems. Install support at planting time to avoid disturbing roots later. The Florida weave system — alternating stakes with twine woven around plants — supports entire rows efficiently.

Pruning indeterminate tomatoes — removing suckers (shoots emerging from the crotch between stem and branch) — maintains plant vigor and channels energy into fruit production. Prune to a single or double leader for maximum fruit size; allow more suckers for higher yield at smaller size. Peppers and eggplants generally require little pruning beyond removing crossed or damaged branches.

Two major tomato diseases warrant attention. Early blight (Alternaria solani) begins as brown spots with concentric rings on older lower leaves, spreading upward. Prevent by avoiding overhead watering, maintaining mulch, ensuring good air circulation, and rotating crops. Late blight (Phytophthora infestans) — the same pathogen that caused the Irish famine — spreads rapidly in cool, moist conditions. Dark, water-soaked lesions appear on leaves, stems, and fruit. It moves quickly enough to destroy an entire planting. At first sign, remove and bag affected material; treat preventively with copper-based fungicide.

Blossom end rot appears as dark, leathery decay at the flower end of fruits. It results not from disease but from calcium deficiency — specifically, the plant's inability to deliver calcium effectively to developing fruits due to irregular watering causing fluctuations in calcium uptake. Prevention lies in consistent soil moisture through drip irrigation and mulching rather than calcium supplementation (since most soils have adequate calcium).