By Jasminam
United Kingdom 
I'm a novice gardener and don't know much about pests and plant diseases. I've looked it up in Veg and Herb Expert book, but I'm not certain what's destroying my young marrow plant leaves and what to do about it.
Marrows are kept in a greenhouse in a conservatory at night and taken out during the day. I water them in the evening after the sunset, but not every evening if the soil is wet from the rain.
I've attached photos to show what's happening. I couldn't see any bugs or eggs on the stems or the leaves. One has green spots, one has a hole, some look like they've been eaten, some look scorched and wilting, and quite a few have areas with different shade circles that look embossed.
Any ideas are much appreciated.
Ta
Jasmina
5 Jun, 2014
Answers
As Myron says, nothing out of the ordinary so far.
Do keep an eye out for mosaic patterns on the leaves, and you may need to move them to much larger containers or open ground, they tend to be big, hungry and thirsty plants.
5 Jun, 2014
The spots don't look urgent to me, but they do look like minor drought damage. Remember that squash of any kind--and most plants, in general--don't like to wilt between waterings. Any time they wilt, they will get more damage.
5 Jun, 2014
Thanks for the advice and reassurance Myron, Teadrinker and Tugbrethil.
6 Jun, 2014
The leaves in the pictures look pretty healthy to me. The small spots on the leaves are probably caused by water droplets landing on on the leaves.
5 Jun, 2014