Greenhouse tomatoes - tops shivelling

[DaveIoM]

For the past couple of years my tomatoes have started really healthy, good strong growth then when they get about 3 feet tall, after about the 2nd truss, the tops look slightly shivelled and growth is severely slowed.
At first glance it looks like lack of water but they get watered every day and the compost never fully drys out. The picture* is of Gardeners Delight but other varieties suffer the same.
They are grown in large pots, compost is 50% multipurpose B&Q and 50% amenity site soil improver ( green waste composted ).
Any ideas of most likely cause?
* I will read through the stickys on how to post the picture

[veggiechicken]

Hi Dave and welcome.
You may not be able to add photos until you've made a few more posts.

Are they getting too hot - direct sun?
Are you feeding them?

[DaveIoM]

Thanks for the welcome and rapid reply.
I haven't fed them this year yet but did last year with Tomerite. Yes they could be too hot as it is a south facing greenhouse but not sure what else I can do to cool them down. The greenhouse has 2 roof vents and 2 louvered side windows. Last year I also shaded the roof. What is too hot 30C+ ?
Work tomorrow so bedtime now but back tomorrow
Thanks
Dave

[veggiechicken]

I've put shading on the roof of my GH as the toms have looked very wilted in this heat. It was 40+ some days.

Good night!!

[nickdub]

Make sure they are getting plenty of water during the day. Depending on what the plants are growing in that can involve either watering them 3 times a day in hot sunny weather, or putting in some sort of automatic system which could be as simple as capillary matting.

If you find the plants are still wilting then you may need to put some sort of shade netting over the roof of your GH.

[It never rains..it pours]

I would suggest the problem is that compost mix. Had same issue here last year at 30c + days. This year used 50% clay soil in the mix and they are much more tolerant to the heat.

[Jungle Jane]

Have you pinched out all the side shoots? Sometimes there’s a hidden one growing away taking all the plants energy & this could be slowing it down?

[DaveIoM]

Thanks for all the replies, very helpful.
The side shoots are all removed. They are in pretty big pots that have a an inch or two at the top that I fill with water every eve. The compost is still slightly damp next day so they are not drying out completely.
Rather than a wilt it is more the tops are tightly curling up on themselves and growth slows right down.
There are no bugs and no signs of disease so I suspect it is heat related as all plants are affected at the same time. It could also be related to the compost so I will try the clay idea next year.
What do you think about food. I never feed too early as the amenity site 'compost' looks quite rich. Do you think a tomerite feed now will help?

[Jungle Jane]

Some of the tops of my tomato plants are curling like that,it’s happened before,my plants are all outside I don’t have a greenhouse,I feed occasionally with liquid seaweed. I think it’s something to do with this-

“In early summer, the nights can be cold and the days very warm. This fluctuation of temperatures is the main cause of what can sometimes be a very alarming degree of leaf curling. The plant is unable to cope with the accumulation of carbohydrates that occurs if nights are too cold for plant physiological functions to occur normally. Fortunately this does not seem to be a serious cause of loss of crop and usually disappears of its own accord as the nights begin to get warmer in late summer.”
https://www.rhs.org.uk/advice/profile?PID=391

[DaveIoM]

Thanks Jane
More to think about. Reading your RHS link it could even be traces of hormone weedkiller in the amenity site compost. I think I will experiment with different composts and clay next year as well as doing my best to regulate max and min temperatures.

[It never rains..it pours]

Thanks Jane
More to think about. Reading your RHS link it could even be traces of hormone weedkiller in the amenity site compost. I think I will experiment with different composts and clay next year as well as doing my best to regulate max and min temperatures.

Experimenting with different soil, additives (manure, seaweed) and varieties is what I do, and makes the whole process a lot more fun. For instance have four varieties of strawberries, 2 are ok to poor, 1 is poor to dead and 1 is fantastic output. Had I just had the poor to dead variety, I would have thought it was me being more hopeless than normal

[Python15]

Oddly enough my Gardeners Delight did exactly the same thing. They've gradually been recovering with no ill effects. I put it down to the extremely rapid growth they've gone through as the Alicante's next door have shown no signs of the same.

[DaveIoM]

Thanks for the further replies. Thinking about it further I have ruled out traces of weedkiller in the compost as many other plants are in it with no ill effects.
Python15 - mine also had extreme rapid growth after potting up to the larger pots before the curling tops stopped growth completely. The question then is what causes the the too rapid growth?
I will experiment with the compost and better temperature regulation next year. Thanks to all.

[Scarlet]

How big are your pots?
Watering from the top isn't the best to be honest. Sit your pots in trays and water from the bottom - they will take up what they need.

[Squingy]

Especially if they have or have had a bluish tinge it could be too much/strong fertiliser. The plants 'burn' and start to curl like you describe. Good luck.