Great looking tomatoes but still green
If you want to know how to encourage tomatoes to ripen on the plant, then read on. It’s around the middle of September that temperatures drop and ripening outdoors becomes an issue.
However, at that time of the season, you probably have some wonderful looking trusses of tomatoes on your plants … the only thing is, the tomatoes are still green!
If the tomatoes on the lower trusses have reached their full size but are taking their time to ripen, there are a number of things we can do to help the process along.
- Reduce nitrogen and increase potassium (potash). Too much nitrogen can delay ripening.
- Remove all side shoots and stop the plants by pinching out the top of the main growing stem – on tall varieties.
- Remove all flowers or very small tomatoes that won’t reach full size before the end of the season.
- Pick tomatoes as soon as they start to turn colour.
I mentioned last week that stress can encourage tomatoes to ripen on the plant – here are a few tips on how to stress tomato plants. This is best done towards the end of August.
- This can be done by reducing watering frequency – longer periods between watering. Of course you need to be careful not to allow plants to wilt.
- Heavy pruning of leaf branches, if tomatoes have reached full size, will shock plants into ripening their tomatoes.
- Cutting some of the roots by sticking a trowel into the soil about 4 or 5 inches from the stem base – a bit extreme maybe but it can work as a last resort at the end of the season!
Professional growers sometimes use a “forcing solution” to speed-up the ripening process. One such solution is GHE Ripen. It gives a plant a strong signal that it is coming to the end of its life. The plant reacts by speeding the ripening process, in a last effort to reproduce.
To encourage picked tomatoes to ripen. This is a lot easier … all you need to do is to put them into a large bowl with a ripe banana or other very ripe tomatoes. The gas that is produced by ripe fruit encourages the unripe tomatoes to ripen.
Of course there is always fried green tomatoes but we would rather have the ripe ones – especially if we are going to save seeds for next season!
There is not a lot we can do about blight once it gets established but taking preventative measures can help – especially if we know that blight is likely to appear in our part of the world.
Here’s a link to a website that keeps watch on the incidents of blight around the UK – just add your postcode. It is meant for those who grow potatoes but tomatoes and potatoes have blight in common!
How to recognise late blight
There are two types of blight – early and late.
Early blight is shown in the photo below, it has round concentric rings – almost like an eye shape.
Late blight (the one we call blight) usually starts by affecting leaves with patches of brown up to the edges of the leaves. This makes its way to the stem and then eventually the tomatoes.
In the photo above, the stem has turned dark in colour and the tomatoes have started to turn brown and soft.
The season so far
So far, August has been quite wet here in Devon though it should be improving this weekend. Several continuous days of wet weather in August is likely to produce late blight.
I remember in August 2008 my wife and I went to the Edinburgh Festival and it rained for about two weeks non-stop, both in Edinburgh and the West Midlands where I used to live. We arrived home to a garden full of blight – all the outside plants were affected and most of the tomatoes unedible.
Of course these days we have blight resistant varieties such as Crimson Crush, Mountain Magic and Lizzano but even they may show signs of blight on their leaves but the fungal disease should not progress further.
Here is a link for more info on how to avoid bliight: http://www.tomatogrowing.co.uk/html/tomato-blight-treatment.html
I hope that the weather is stays fine in your area!