Tomato Plants Can Get Sunburn?

[leke]

[img]https://I.imgur.com/oposv.jpg[/img]

The leaves looked a bright and juicy green when it was in my grow cupboard. Now it's a dull, matt green with dry yellow edged leaves.

I took this chap out of the grow cupboard today and into the mini green house I have. It was all lush and green, but at the end of the day, when I went to zip the greenhouse cover back on (to protect against the evening chill), I was horrified to find it had been fried (looks like sunburn).
I just don't get it. Plants are supposed to like sun. I monitored the greenhouse in full sun and the temp was only 17C / 63F (it's much cooler outside). In the current position of the greenhouse, it only got about 5 hours of direct sunlight and had damp soil.
What am I doing wrong here?

[rainbowgardener]

It likes sun, but only after it gets used to it. The amount of light in your grow box is so much less than even a cloudy day outdoors, they do get burned easily at first, while still tender.

I'd bring it back in for awhile, until it is recovered, and then harden it off more gradually. When I bring things out the first time, I put them in a spot where they get NO direct sunlight. I gradually move them a step at a time to more exposed locations.

[leke]

It likes sun, but only after it gets used to it. The amount of light in your grow box is so much less than even a cloudy day outdoors, they do get burned easily at first, while still tender.

I'd bring it back in for awhile, until it is recovered, and then harden it off more gradually. When I bring things out the first time, I put them in a spot where they get NO direct sunlight. I gradually move them a step at a time to more exposed locations.

Oh, I thought hardening off was only to do with temperature, but it makes sense they would become accustomed to a certain environment. That's really useful to know thanks
It's a good job I didn't bring everything out of the cupboard.

[gixxerific]

Oh, I thought hardening off was only to do with temperature, but it makes sense they would become accustomed to a certain environment. That's really useful to know thanks
It's a good job I didn't bring everything out of the cupboard.

It's a little of both as well as getting used to wind. They can can get wind burnt too. It's just a way different environment outside than inside.

I work outside and even I take time to acclimate to different weather patterns. Living here around the St Louis area we can get 50+ degree temp swings in and hour, with snow following. Yes it happens not often but it does. Even the little swings from 90's one day to 60's - 70's even the 80's the next day, it takes some getting used to before you feel comfortable or at least back to normal.
Yeah right like I'm ever normal!!!!