You’ve watered, fed, supported, and watched your tomato plants grow beautifully all summer. The leaves are lush, the fruit is forming… but those tomatoes are still green. Sound familiar?
If your tomatoes are refusing to ripen, you're not alone. This is one of the most common questions we get at this time of year – and the good news is, it’s usually nothing to worry about. With a few simple tweaks, you can help your crop along and get those juicy red tomatoes you’ve been dreaming of.
Here are the most common reasons your tomatoes might not be ripening – and what you can do about it.
1. They Just Need a Bit More Time
Let’s start with the obvious – tomatoes don’t all ripen at once. Depending on the variety, it can take 6–8 weeks for fruit to ripen after it first appears.
If your plants are otherwise healthy, it may just be a waiting game – especially if it’s your first time growing them or it’s been a slow start to summer.
Tip: Keep an eye on the lower trusses – they should be the first to ripen. Patience is part of the process!
2. Not Enough Sunshine
Tomatoes love the sun – they need warmth and light to turn from green to red. If it’s been cloudy, rainy, or your plants are tucked into a shady spot, ripening will naturally slow down.
What to do:
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Trim back some of the larger leaves to let in more sunlight.
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If your tomatoes are in pots, move them to the sunniest spot you can.
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In greenhouses, open vents and remove overcrowded growth for better light circulation.
3. Too Much Nitrogen, Not Enough Potassium
Have your plants gone big and bushy, but with little fruit colour? You might be overfeeding with a high-nitrogen fertiliser, which encourages leafy growth at the expense of fruit ripening.
What they need instead: A high-potash feed, like Tomorite, is ideal for promoting flower and fruit development.
Tip: Switch to a tomato-specific liquid feed once fruits start forming, and apply regularly.
4. Lack of Air Circulation or Overcrowding
If your tomato plants are tightly packed or you’ve let them run a bit wild, ripening can stall due to poor airflow and too much energy going into foliage.
Quick fix:
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Prune some of the side shoots and older leaves to allow air and light to reach the fruit.
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Focus the plant’s energy on ripening existing fruit rather than producing more leaves or flowers.
5. The Fruit Has Plateaued – Especially at the End of a Truss
Tomatoes don’t always ripen evenly – it’s normal for the fruit at the top or end of a truss to lag behind the rest. If the first few have turned, the rest will usually follow… eventually.
Speed things up with the banana trick: Place a ripe banana near the tomatoes – the ethylene gas it emits helps trigger ripening.
6. The Weather’s Been All Over the Place
Tomatoes are fussy. Cool nights, hot days, heavy rain, and sudden temperature swings can all delay ripening – and let’s be honest, we’ve had a bit of everything lately!
If your plants look healthy, they’ll likely catch up as soon as the weather settles.
✅ Quick Ripening Tips:
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Move potted plants into full sun.
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Trim leaves to allow light and airflow.
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Switch to a high-potash tomato feed.
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Try the banana-in-a-bag trick for harvested green tomatoes.
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Remove small or excess fruit so the plant can focus on ripening what’s already growing.
🍅 Still Got Questions?
Pop into Kings Garden and Leisure in Exmouth or Sidmouth and speak to our team – we’re always happy to help with practical tomato-growing advice and have everything you need in stock, from tomato feed and pruning tools to grow bags and greenhouse accessories.
You’ve done the hard part – now let’s get your tomatoes ripening!