How to grow tomato in Australia 🍅

Tomatoes need warm soil (consistently above 16°C), no frost risk, and enough time to fruit and ripen before either the heat peaks or the cool returns. That combination plays out very differently across Australia's climate zones.

Tomatoes are almost always grown from seedlings in Australian conditions rather than direct-sown seeds, which makes the timing calculation slightly different — you're working from when seedlings go into the ground, not when seeds are sown. If you're starting from seed, add 6–8 weeks to the schedule above.

When you're buying seedlings at the nursery, you'll notice tomatoes fall into two different growth habits. Some varieties — most heirlooms, most cherry tomatoes — keep growing taller and taller all season, sometimes reaching two metres or more, and they need a tall stake or a wire cage to hold them up. Others are compact bush varieties that grow to a fixed height (usually 60–90cm) and stop. The bushy ones are self-supporting or need only a short stake, and they tend to produce all their fruit in a shorter burst rather than continuously over months. Neither is better — it depends on your space and how you want to harvest.

Spacing: 45–60cm between plants, rows 60–90cm apart. Taller, vining varieties need the wider end of that range; compact bush types can be planted a little closer. Tighter planting increases humidity around the plants and disease risk, especially in coastal climates.

Depth: Plant deep. Tomatoes produce roots along the buried portion of their stem — a tall, leggy seedling planted so only a few leaves stick out will develop a far stronger root system than one planted at the same level it was growing in the pot. Remove lower leaves and bury up to two-thirds of the stem.

Staking and support: Taller, vining varieties need staking or a cage from planting day, not after they've flopped over. A single stake tied loosely with soft ties every 20–30cm as the plant grows is the most practical approach for most home gardeners. Tomato spirals work well for cherry tomatoes.

Soil: Tomatoes are heavy feeders. A well-composted bed with a handful of blood and bone or pelleted chicken manure worked in at planting gives a good start. They prefer slightly acidic soil (pH 6.0–6.8). Consistent soil moisture is more important than total water volume — irregular watering causes blossom end rot and fruit cracking.

Tomatoes grow well in all three — with some important differences in how you manage them.

In-ground is the most forgiving approach. The soil volume is effectively unlimited, which means roots can go deep, moisture is more stable, and plants are more resilient through hot spells. The downside is that soil-borne diseases (like fusarium wilt or root-knot nematode) can build up over successive seasons — if you've had problems before, rotating tomatoes to a different part of the garden each year helps significantly.

Raised beds sit between pots and in-ground for most practical purposes. You get better drainage than compacted in-ground soil, easier control of soil quality, and the bed warms up faster in spring. A raised bed at least 30cm deep gives enough root run for full-size tomato plants. The main risk is that shallower beds (under 20cm) dry out too quickly in summer — water management becomes more work.

Pots are the most common choice for balcony and courtyard gardeners, and tomatoes can absolutely be grown in them — but they need to be genuinely large. A pot that looks like it should be big enough usually isn't. For full-size tomato plants, you need a pot that holds at least 40–50 litres of potting mix — roughly the size of a large bucket, or bigger. Smaller pots restrict the root system, dry out fast, and produce plants that fruit poorly and struggle through any heat. Cherry tomato varieties are better suited to pots than large slicing types.

Regardless of pot size, the biggest challenge is watering. Pots dry out fast in warm weather — daily watering is common through summer, and missing a day during a heatwave can stress the plant badly. Self-watering pots with a reservoir make a real difference and are worth the extra cost if you're serious about pot-grown tomatoes. Use a premium potting mix, not cheap fill — and add a handful of slow-release fertiliser at planting, because unlike in-ground soil, potting mix has limited nutrients that get depleted over the season.

One advantage of pots: you can move them. A tomato in a pot on a north-facing balcony can be shifted out of the afternoon sun during a heatwave, or positioned to catch more winter warmth in Melbourne or Hobart where every degree helps.

Tomatoes need full sun — 6 to 8 hours of direct sunlight daily. In Darwin and tropical far north QLD, a little afternoon shade in the dry season can reduce heat stress during the hottest hours without significantly affecting yield. In all other zones, more sun is more fruit.

Water deeply and consistently rather than little and often. A deep watering every 2–3 days in warm weather (more frequently in very hot periods) encourages roots to go deep rather than staying near the surface. Shallow roots make plants more susceptible to heat stress. Drip irrigation or soaker hoses at soil level are more effective than overhead watering — wet foliage through the night is an invitation to fungal disease.

Mulch heavily around the base of the plant to keep soil moisture consistent and regulate soil temperature. This is one of the highest-return things you can do for tomatoes, especially in hot inland climates.

Pick tomatoes when they've fully coloured — red, yellow, orange, or whatever colour the variety is meant to be — and when they give slightly to gentle pressure. If in doubt, leave them another day. A tomato picked a day too early has noticeably less flavour than one left to ripen fully on the vine.

In a hot summer, very ripe tomatoes can overcook on the vine. Pick regularly when conditions are extreme — even if a tomato is only partly ripened, it will continue to ripen off the vine at room temperature. Never put a ripening tomato in the fridge — cold destroys the flavour compounds.

Keep picking to keep the plant producing. A plant loaded with ripe fruit stops setting new flowers.

Blossom drop is when flowers appear but fall off before setting fruit. Almost always caused by temperature extremes — either nights below 10°C or days above 35°C cause the plant to abort flowers. In Melbourne, this means late September plantings may lose their first flush of flowers to cold nights. In Darwin or Alice Springs, it means plantings that run into the hot season lose flowers to heat. The solution is timing — get planting right and this largely takes care of itself.

Blossom end rot — a dark, sunken patch on the bottom of the fruit — looks like a disease but it's actually a calcium problem caused by inconsistent watering. When the soil dries out and then gets flooded, the plant can't take up calcium properly. Affected fruit is edible (just cut the damaged end off), but the fix is more consistent watering, not adding calcium supplements. Mulching helps significantly.

Tomato fungal diseases (early blight, late blight, septoria leaf spot) are common in humid coastal climates — Brisbane through Sydney's summer especially. They show up as brown or yellow spots on lower leaves that spread upward. Prevent by watering at soil level rather than overhead, spacing plants well for airflow, and removing lower leaves that touch the ground. There's no cure once established, but removing affected leaves and treating with a copper-based spray can slow the spread.

Fruit cracking — circular or radial splits in ripe fruit — is caused by rapid water uptake after a dry spell, usually when heavy rain follows a dry period. Consistent mulching and watering reduces it. Pick fruit that's close to ripe before heavy rain if cracking is a regular problem in your garden.

Plant near: Basil (the most classic combination in the kitchen garden; aromatic oils may deter aphids), parsley, marigold (deters nematodes in the soil), and carrots.

Keep away from: Fennel — it releases compounds into the soil that inhibit most vegetable crops growing nearby. Also keep away from brassicas (broccoli, cauliflower, cabbage) — they compete for similar nutrients and don't perform well together.

Tommy Toe — A small cherry tomato that's been grown in Australian gardens for generations. Intensely flavoured, crack-resistant, and far more disease-tolerant than most large varieties. An excellent choice for humid climates and for first-time tomato growers. Available widely from heritage seed suppliers. Produces continuously over a long season on vigorous vines.

Grosse Lisse — The quintessential large red slicing tomato in Australian gardens. Reliable, productive, and widely available as seedlings from nurseries. A compact, bushy plant that doesn't need a tall stake — ideal if space or support is limited. Suited to warm and cool temperate climates. Not the best choice for tropical or subtropical zones where heat and humidity cause problems.

Roma — A paste tomato. Drier, meatier flesh than salad types. Excellent for cooking, preserving, and drying. More heat-tolerant than most large varieties, which makes it a better performer in warmer zones. Bushy plant, good for pots at 40+ litres.

Black Russian — A popular heirloom with dark, complex-flavoured fruit. Better suited to cool temperate climates where it gets the warm days and cool nights it needs to develop full colour and flavour. A tall, vining plant that needs a solid stake. Doesn't perform as well in hot, humid conditions.

Sweet 100 — A reliable, high-yielding cherry tomato on long, vigorous vines. Excellent disease resistance and fruit that keeps ripening over a long period. One of the best choices for all climate zones including subtropical. Good for pots if the container is large enough — at least 40 litres, with a tall stake or trellis.

Rouge de Marmande — A ribbed, old French variety that does particularly well in cooler climates with its shorter season. Excellent flavour. Compact, bushy plant. Available from Diggers Club and heritage seed suppliers.