Tomatoes are New Zealand's most-grown home garden vegetable. They're also frost-tender, so timing matters more here than with almost any other crop. Plant too early and a late frost will kill young plants outright. Plant too late and they run out of warm weather before the fruit ripens.
Plant too early and a late frost will kill young plants outright.
In Auckland and the Bay of Plenty, plant out from September through to December. In Waikato, Wellington and Canterbury, wait until October, once the risk of frost has genuinely passed, then keep planting through to December. In Otago, hold off until November or December. Not sure which end of your region's window to use? The traditional nationwide rule of thumb is to plant tomatoes around Labour Weekend, in late October.
Tomatoes need full sun and a sheltered spot. Wind rock and cold snaps are two of the biggest causes of failed transplants. Space plants around 50cm apart and stake or cage them early, before they sprawl: most home garden varieties are indeterminate and keep growing taller through the season. Expect a mature plant to produce around 3-5kg of fruit over a full season, and 70-85 days from transplanting to first ripe fruit.
Water consistently rather than in occasional big soaks. Irregular watering is the main cause of blossom end rot, where the base of the fruit goes dark and leathery. Early and late blight and verticillium wilt are the other diseases to watch for, especially in humid or wet summers. Good airflow around plants and avoiding overhead watering both help.
Aphids, whitefly, tomato-potato psyllid and caterpillars are the pests most home gardeners run into. Basil, carrots, celery, parsley, chives, onions, marigold and asparagus are all good companions for tomatoes. Avoid planting them near brassicas, fennel, potatoes or sweetcorn: these either compete for the same nutrients or share disease and pest problems.