What's wrong with my Rocket?

I put some rocket in about a month ago and it's been growing in my greenhouse. All the leaves seem to be shriveled at the edges. They look scorched but they don't get full sun or watered until the evening so wouldn't have thought it's that. The temp has been going up to hight 20's though during the day so wondered if that's too warm for rocket. It hasn't gone below 5 degrees at night so don't think it's frost damage. Ive hopefully Any ideas?

It doesn't need to be in the greenhouse. Stick it in the ground outside, give it a good watering and it'll be fine.

We don't mind if rocket even goes to seed, as the texture of the leaves becomes more like spinach, and the heat and flavour is just marvellous!

I was going to pot on a tray this arvo, but snoozed and lost the slot..:0(

It's a fickle plant, but as above posts, just needs knocking about a bit...