By the end of August the tomato plant on my balcony looks like a person who has been at a wedding since noon: still upright, still producing, but visibly done. There are flowers at the top that will never become anything, leaves going yellow at the bottom, and a stubborn cluster of green fruit halfway up that I keep willing to turn. This is the point in the season where most of us keep doing what we did in June — water, feed, hope — and that is exactly the wrong instinct.
The final weeks are about subtraction. You are no longer growing a plant; you are ripening fruit. Everything you do should serve that one goal.
Stop the plant from starting anything new
Find the highest truss carrying fruit that has a realistic chance of ripening, count two leaves above it, and cut the growing tip off there. It feels brutal the first time. It is the single most useful thing you can do in late season, because it tells the plant to stop investing in new stems and flowers and to put everything into what it already has.
While you are there, pinch out any new side shoots on cordon varieties and snap off flower trusses that have only just opened. They will not make it to a ripe tomato before the light goes, and every one of them is drawing energy away from the fruit that will.
Take the lower leaves off, but not all of them
Remove leaves below the lowest ripening truss, especially anything yellowing, spotted or lying on the soil. This improves airflow at the base, keeps water off the foliage, and reduces the damp, still conditions that late-season fungal problems love. On a balcony where plants are packed close together, this matters even more than it does in an open bed.
Do not strip the plant bare, though. Leaves are how fruit gets its sugar, and the ones above and around a truss are still doing real work. The rule of thumb: clear the legs, leave the shoulders.
Water less, and water evenly
Cutting back slightly on water in the last stretch concentrates flavour — this is why late tomatoes often taste better than the glut in July. But the emphasis is on slightly and on evenly. A plant that dries out completely and then gets drenched will split its fruit within a day, and split fruit rots fast in warm weather.
Stop feeding high-nitrogen fertiliser entirely; you do not want new leafy growth now. If you feed at all, keep it low and stop about two weeks before you expect to clear the plant. Containers dry faster than beds, so check by pushing a finger into the compost rather than by looking at the surface.
Harvest earlier than feels natural
A tomato does not need the plant to ripen. Once it has begun to blush — that first shift from green to pale orange at the base — it will finish perfectly well on a windowsill or in a bowl on the kitchen counter. Picking at that stage takes the weight off the plant, frees energy for the fruit behind it, and protects your crop from a sudden cold snap or a rain-splitting night.
Handle them gently, keep them out of the fridge, and check daily. A bowl of blushing tomatoes ripening indoors is one of the small pleasures of September, and it beats watching one perfect specimen go over while you wait for the whole truss to catch up.
Should I pick tomatoes green or leave them on the plant?
Anything showing even a hint of colour change should come in — it will ripen indoors with no loss of flavour, and it is safer there. Fully green, hard fruit is a judgement call: if warm weather is holding, leave it, but once nights turn cold or blight appears in your area, bring it all in. Green tomatoes ripen faster in a closed paper bag with a ripe banana or apple, and whatever refuses to turn becomes chutney, a fried breakfast side, or a sharp green salsa.
What do I do with the plants when they're finished?
Cut them down at the base, and only compost the foliage if the plant was genuinely healthy — anything with brown blotches, mould or wilt should go in the bin rather than back into your soil. Remove the stakes and wash them, because spores overwinter happily on wood and string. Container growers should empty the old compost onto beds or borders rather than reusing it for tomatoes next year, and give the pot a scrub before it goes into storage; starting clean in spring saves you a whole season of mystery problems.
