Ngyaon köszönöm a válaszokat, majd ellenőrzöm, van-e rajtuk valami - sosem néztem, az igaz, mert kizártnak tartottam, hogy ez lenne a baj.

Érdekes, kínomban angolul kerestem rá egy perce a következő szavakra "tomato growing uv" - ezt már máskor is megtettem, de nem volt eredmény, mert a growingot kifelejtettem, s csak arról meéltek, jó az UV ELLEN a p.

Most viszont ezt kaptam, válaszul egy dél-afrikai (!) gondra:

 

"Poenie, you’re doing the right thing by keeping your tomatoes in a hothouse, but in these temperatures it can also become very dangerous for the tomatoes. Over exposure to UV and intense sunlight can quite simply scortch your tomatoes dry.

The best temperatures for tomatoes are from 18C to 26C, once you get above 30C that’s the danger zone for the tomatoes.
Why? Well, for one, if its hot and intense UV rays are pounding those tomatoes, the humidity in the air acts like a magnifying glass so it just burns them more intensily. If they don’t have enough water they’ll simply die from getting burnt.

Two, the humidity around the tomato plant during the day can cause problems at night when the temperature is cooler and some of that water vapour turns to a water residue around the blant, inviting all kinds of molds to grow on the tomato(mold loves tomato)

Your tomato plants and keel over and die quickly :)

What is the solution?

1. You need to protect those tomatoes from the intense UVs during the most intense daylight hours.

Obviously, the tomato plant needs some sunshine, although, it will be getting it alot there anyway.

However, During the intense UV times between 11AM and 3PM, you can cover the greenhouse with a tarp or something to shade out the sun, I highly recommend this. (My grandfather would do this religiously during the hot summers)

This will also help regulate the temperature in the greenhouse as well.
2. Keep the greenhouse WELL ventilated at all times. Tomatoes NEED fresh air, otherwise they will be struggling to grow, the air needs to be recycled constantly for them to thrive. If you can manage to get a flow of air through the greenhouse, this will make them very happy.

You can even experiment by shading out parts of the greenhouse, and seeing if you can leave it permantently shaded, so that it allows enough daylight so it’s not pitch black in there, but enough shading to reduce the temperature into the 20s or low 30s.

If you read my book “Organic Tomato Magic”, you’ll know that tomatoes are not dependant on Sunlight but more on water. They do not need masses of sunlight, contrary to popular belief. Give them Water and Air, and some daylight and they will thrive."

Én is ilyesmire tippeltem, de eddig sehol sem leltem rá...Elnézést a hosszáért, ha kell, legközlebb lefordítom.