Cherry tomatoes are among the most forgiving tomatoes for a balcony, provided you give them three things: a big pot, at least six hours of direct sun, and water that never swings between bone dry and soggy. Most failures on balconies come from small pots, shade and wind, not from the plant itself.

This guide is about the pot-and-balcony angle. It does not cover in-ground tomato timing, which varies a great deal across Australia.

How big should the pot be?

Go bigger than feels necessary. The RHS suggests one plant per 30 to 45 cm pot, and Australian advice from Organic Gardener is a pot at least 400 to 500 mm across for tomatoes. Treat the larger end as a safer target on a hot balcony, because a bigger volume of mix holds moisture longer and swings less between waterings.

• One plant per pot. Two plants in one pot compete for water and nutrients.
• Drainage holes are essential. Raise the pot slightly so water can escape and the base does not sit in a puddle.
• Use a good-quality vegetable potting mix rather than garden soil, which compacts in pots.
• Check the weight. A large pot of damp mix is heavy. Confirm what your balcony, or your strata or landlord rules, allow before loading it up.

Choose varieties labelled dwarf, patio or determinate if space is tight. A tall indeterminate cherry can reach well over head height and become a wind sail.

Which balcony aspect gives enough sun?

In Australia, the sun tracks across the northern sky, so aspect matters:

The target is a minimum of six hours of direct sun a day; the University of Arizona lists too little sun among the causes of poor flower set. Neighbouring buildings, overhangs and balustrades change this a lot, so watch your balcony on a clear day and note when direct sun arrives and leaves. Actual hours depend on your latitude, season and surroundings.

What do you do about wind and support?

Balconies funnel wind, and wind dries pots and tears foliage. The RHS warns that tall tomatoes in pots can become top-heavy, so a sheltered spot matters.

1. Install the support at planting time, so roots are not damaged later.
2. For a tall plant, build a cage or tower inside the pot from stakes and twine, as Organic Gardener describes, and tie the main stem as it grows.
3. Place the pot against a wall or solid balustrade rather than the open edge, and keep it away from any ledge where it could be knocked off.
4. In strong winds, shift pots to a protected corner and tie stems firmly, with soft ties.

A clear screen or lattice windbreak can soften gusts, but do not block all sun to do it.

How do you keep watering consistent?

Pots dry out quickly. The RHS notes container plants may need daily watering in hot weather, and uneven moisture is linked to splitting and blossom end rot. Blossom end rot shows as a dark, sunken patch at the base of the fruit. The Arizona extension ties it mainly to moisture stress and over-fertilising, rather than a simple lack of calcium in the mix.

Habits that help:

• Check by pushing a finger into the mix. Water when the top few centimetres feel dry, and water until it drains.
• Water at a regular time, often early morning on hot days.
• Mulch the surface lightly to slow evaporation.
• Do not let a saucer hold standing water for days.
• Affected fruit will not recover, but later fruit is usually fine once watering steadies.

In heatwaves, wind and reflected heat from walls increase demand. Our guide to watering potted plants through summer heat goes deeper on this. Always check any local water rules yourself.

How and when should you feed?

Potting mix has limited nutrients and frequent watering washes some out, so container tomatoes usually need feeding. A common approach is a tomato or potassium-rich liquid feed through the fruiting period; the RHS suggests starting once the first fruits swell, and Organic Gardener mentions a potassium-rich liquid feed. Follow the product label.

More is not better. Too much fertiliser, particularly nitrogen, can produce leafy plants with fewer fruit and is associated with blossom end rot. Never feed a dry plant.

Do balcony tomatoes need hand-pollination?

Tomato flowers are self-fertile, but they need movement to release pollen. Outdoors, wind usually does it. On a sheltered or high-rise balcony with few insects and little breeze, help it along:

1. Pick a dry, mild morning when flowers are open.
2. Tap the flower stem or gently shake the whole truss for a few seconds.
3. Repeat every day or two while flowering.

Both the RHS and University of Arizona describe tapping or shaking flowers to help pollination. No tools or sprays are needed.

Why are flowers dropping in hot weather?

Flower drop is common and often temporary. Causes include heat, cool nights, uneven watering, too little sun and strong wind (see the Arizona list). The exact temperature thresholds in US sources are not tied to Australian conditions, so use them as a guide only.

What you can do:

• Keep watering steady.
• In extreme heat, give afternoon shade with a lightweight shade cloth or by moving the pot.
• Reduce wind exposure.
• Be patient. Flowering usually resumes when conditions ease.

Timing varies by climate. In tropical areas, tomatoes generally suit the drier, cooler months, while in subtropical and temperate regions plant after frost risk and in spring or autumn, as local conditions allow. Cool highlands and Tasmania should wait for warmth.

When and how do you harvest?

Pick cherry tomatoes when fully coloured and slightly soft, usually in trusses as they ripen over days or weeks. Regular picking keeps the plant cropping. Fruit that splits after heavy rain or irregular watering can still be eaten promptly.

At the end of a long season, or if plants stall in extreme heat, keep picking and keep watering. A tired plant often recovers when nights cool, and fruit ripened slowly in mild weather tends to be easier to manage than a rush of fruit during a heatwave. Note your planting date and first ripe fruit so next season’s timing is based on your own balcony.

Common mistakes

• Pots too small, or one pot for two plants.
• A south-facing spot with too little light.
• Skipping the stake or cage, then staking late.
• Letting the pot dry out, then drenching it.
• Heavy feeding to fix a watering problem.
• Leaving tall plants fully exposed to wind.

For the wider picture of living with limited space, see this overview of balcony gardening across Australia, and for what else grows well alongside your tomatoes, browse the guide to growing vegetables in pots.