Heirloom tomatoes are the hardest tomatoes to judge, and the most worth judging well. Unlike a modern red variety, where ripe means red, an heirloom may be ripe when it is green-striped, yellow, pink, orange or nearly black — and the colour alone will not tell you. The reward for learning to read them is a tomato with flavour no supermarket variety can match: sweet, rich, complex, and completely different from one variety to the next.
Heirloom tomatoes take 70–85 days to mature, according to the Garden Grove crop data. They are a tender vegetable in the Solanaceae family with high water needs, so they need warm weather and steady, generous watering. Most heirlooms are indeterminate, fruiting over a long season, and the fruits are large, heavy and often ribbed or irregularly shaped — all of which changes how you pick and handle them. For the full growing picture, see our growing guide for heirloom tomatoes, and use the Harvest Date Calculator to work out your picking window from your sowing date.
Heirloom tomatoes at a glance
| Growing factor | What heirloom tomatoes need |
|---|---|
| Days to maturity | 70–85 |
| Category | vegetable |
| Family | Solanaceae |
| Cold tolerance | tender |
| Water needs | high |
Signs an heirloom tomato is ready to pick
Colour is a guide, not a rule, for heirlooms. You need to know what colour your variety is supposed to be when ripe — a Green Zebra is ripe when its green stripes turn yellowish, a Cherokee Purple is ripe when it is dusky purple-red, a Brandywine is ripe when it is deep pink, and a yellow heirloom is ripe when it is golden. Read the variety description when you sow, and write the expected ripe colour on the plant label. Within that colour, the sign is a deep, even tone with no pale green shoulders left, and a slight softening of the colour as the fruit finishes.
Feel is the most reliable test across all heirloom varieties. Hold the fruit gently and give it the lightest squeeze: a ripe heirloom yields slightly under your fingers, like a ripe peach. It should feel heavy for its size and the skin should have a slight shine. A fruit that is rock hard is not ripe; a fruit that gives easily and feels soft is overripe. Test the blossom end, the bottom of the fruit, which softens first — when it yields gently, the fruit is ready.
Smell and the stem are the third check. A ripe heirloom smells fragrant and tomatoey at the stem end, while an unripe one smells green and leafy. The fruit should also separate from the stem with a gentle twist — if you have to pull hard, it is not ready. And watch the shoulders: on many heirlooms the top of the fruit stays slightly green or ribbed even when ripe, so judge the whole fruit, not just the top. For the sauce tomato, see our guide to when to harvest roma tomatoes, and for the small snacking tomato, see when to harvest cherry tomatoes.
How to pick heirloom tomatoes without damaging the plant
Pick heirlooms with both hands. Cup the fruit in one palm to take its weight — a big heirloom is heavy — and twist gently with the other hand until the stem separates, or snip the stem with clean scissors. Never let a large fruit hang from its stem while you cut, and never pull a fruit down, because the weight can tear the truss or snap the stem and damage the fruits next to it.
Support the truss while you work, because a truss of heirlooms is heavy and the vine is under real strain. Pick into a shallow basket or a flat box, in a single layer, and set each fruit down gently rather than dropping it. Heirlooms bruise more easily than modern varieties, and their thin skins and soft flesh show every knock. Do not stack fruit on top of each other in a deep bucket — the ones at the bottom will be crushed.
The best time of day to harvest
Pick heirloom tomatoes in the morning, after the dew has dried but before the heat builds. Morning fruit is cool and firm, bruises less, and goes into storage in the best condition. Fruit picked in the heat of the afternoon is warmer and softer, and a soft heirloom bruises at the lightest touch.
Avoid picking when the plants are wet from rain if you can, because wet fruit is more prone to rot in storage and wet foliage spreads disease. If rain is forecast and fruit is ripe, pick before the rain: a ripe heirloom that takes up water quickly is very likely to split. Pick before you water, not after, for the same reason.
How often to pick
Check heirloom plants every two to three days once fruiting starts. A plant in production will have fruit at every stage, and regular picking keeps it going: every ripe fruit you remove lets the plant put its energy into ripening the next ones. Do not leave ripe heirlooms on the plant to "get better" — once a fruit is ripe, it is at its peak, and leaving it only invites splitting, insects and rot.
Heirlooms are more prone to cracking than modern varieties, especially the big ribbed types, so pick promptly when the fruit is ready and do not wait for a weekend. Because heirlooms are tender, the season ends with the first frost, so make a final harvest before cold nights and bring in the green fruit too — mature green heirlooms ripen indoors. See Zone 6 heirloom tomatoes for an example of seasonal timing, and check your local extension service for frost dates in your area.
What happens if heirloom tomatoes are left too long
An heirloom left too long softens quickly, because the flesh is soft and the skin is thin. The fruit can split at the top — radial cracking around the stem is common in heirlooms — and split fruit attracts insects and mould. Overripe fruit may drop off the plant under its own weight, and fallen fruit on the soil spreads disease.
A slightly overripe heirloom is still usable if it is sound: cut it open, check for mould, and eat it the same day or cook it into a sauce. Heirlooms that are past their best raw often make the best sauce, because their flavour is so intense. But do not leave the crop to over-ripen by neglect — pick on time, and cook the occasional overripe one the same day.
How to store heirloom tomatoes
Short term, store ripe heirlooms at room temperature, stem-side down, in a single layer out of direct sunlight, and eat them within a few days. This is the golden rule for heirlooms: the fridge is their enemy. Cold dulls their flavour and turns their soft flesh mealy, and a refrigerated heirloom never recovers its taste. Only refrigerate a fully ripe fruit you cannot use in time, and bring it back to room temperature before eating.
For longer storage, heirlooms are best preserved by cooking. A glut makes wonderful sauce, soup or roasted tomato portions for the freezer. You can also freeze whole fruit for cooking — the skins slip off after thawing. Do not try to keep fresh heirlooms for weeks; they are a short-storage fruit, and the best storage is a steady picking rhythm through the season.
If you grow a lot of tomatoes and want to plan quantities, the Vegetable Yield Estimator can help you work out how many plants to grow next season.
Succession and continuous harvest tips
Heirlooms are mostly indeterminate, so the plant itself provides the succession — it keeps flowering and fruiting until frost. Your job is to keep it healthy, supported and picked. Water steadily and evenly: irregular watering causes splitting and blossom-end rot, and heirlooms are more sensitive to both than modern varieties. Mulch heavily to hold moisture and water at the base of the plant rather than overhead.
Support the plant well, because the fruit is heavy and a loaded heirloom vine will collapse if it is not tied up. Keep the plant pruned for airflow, since dense, damp foliage is where disease starts, and disease is the main reason heirloom plants stop producing early. Grow more than one variety if you can: different heirlooms ripen at different times and have different strengths, and a mix gives you a longer, more interesting harvest. Browse the full guides hub for more harvest timing advice, and check your local extension service for varieties that perform well in your climate.
Frequently asked questions
When are heirloom tomatoes ready to pick?
When the fruit has reached its variety's ripe colour, feels heavy, yields very slightly to a gentle squeeze — especially at the blossom end — and smells fragrant at the stem. Maturity is typically 70–85 days.
How do I know if a green heirloom is ripe?
Know the variety: some heirlooms are meant to be green when ripe. A ripe green heirloom turns yellowish between its stripes, feels slightly soft, and smells fragrant. Feel and smell are more reliable than colour for these varieties.
Why do my heirloom tomatoes crack?
Cracking happens when ripe fruit takes up water quickly after a dry spell, heavy rain or heavy watering. Water steadily, mulch to hold moisture, and pick ripe fruit before rain. The big ribbed varieties crack more easily than smooth ones.
Should I refrigerate heirloom tomatoes?
No, if you can avoid it — the cold dulls the flavour and makes the flesh mealy. Store them at room temperature and eat within a few days, or cook and freeze a glut.
How do I ripen green heirlooms indoors?
Put mature green fruit in a paper bag with a ripe banana or apple, which releases the gas that triggers ripening, and check daily. Check your local extension service for preserving and ripening advice suited to your area.