Tomatoes - Is it terminal?

[Moggle]

Thanks Tim, will try and reply.

John I assume the scorch would be from cold? As you say, I wasn't exactly gentle with the hardening off, so that could well be it. I'll have another look at the leaves in a bit and examine for paperyness.

[Moggle]

[john_miller]

To be botanically accurate, Moggle, the close atomsphere in your flat will have got the plant into a state of not transpiring very much moisture. Once you put them outside the increased air movement will have increased the moisture loss. The cold will have slowed the rate of flow of moisture from the roots to the stomata (the breathing apertures in the leaf) so moisture will have been pulled from the surrounding leaf cells causing them to dry out and die.

[tim]

Not before time, John!! Where have you been??

When I said 'couldn't be' I meant, of course, from the glorious English sun - at the time it first happened. Fascinating about your type of scorch.

btw - why do toms transpire so frantically? Is it a good thing? This, in itself, could cause tip burn in hot sunshine?? = Tim

[john_miller]

Every plant transpires, Tim. I don't know if tomatoes are frenetic about it, it is just their adaptation, neither good nor bad.
I'm trying to recall if I have seen tip-burn on tomatoes in hot sun. I've seen tip burn caused by cells drowning (mostly happens on tomatoes in greenhouses but I have seen lettuce affected outside) and sun scald on fruit outside. Too many years here, where I guess it isn't significant enough for me to recall, and too many years away from the U.K.?

[tim]

It's just that I sometimes mutter something to myself when I get soaked walking down the rows!! Cus as well. = Tim

[Moggle]

The damaged bits of the leaves are indeed papery and crumbly.

Assuming that it's scorch, dare I hope that the worst has passed. Also, I've removed loads of leaves but have left a few on the plant. Should these be removed or left?

Once again, thanks a load!

[john_miller]

The worst has passed (barring a frost of course!). Leave any remaining leaves on the plant until they are obviously dying (which happens naturally with tomatoes- only the leaves 1.3m from the growing point are actively contributing to the plant while the plant will cause senescence of the rest).
Tim- if you are getting soaked walking down the rows then that is the cause of your tip burn, not the sun. If the atomsphere in your greenhouse becomes saturated overnight then transpirational losses from the plant cannot evaporate into the air. This moisture accumulates on the leaf, especially along the leaf margins. If this moisture then sits on the leaf for prolonged periods (which it will- hours during the spring and autumn)  the marginal cells drown and die. They will presently turn brown- tip burn.

[tim]

I always thought it was the lens effect. Live & learn! = Tim