Some Heartsease getting discoloured - anybody know why?

I've got some Heartsease growing in two propagators with the lid off in my front room window. I keep them fairly well watered.

One lot was repotted a week before the last lot were five days ago. The ones I did five days ago should have been repotted a long time before if the root system was anything to go by (all over the place).

The more recently repotted ones seem to have a problem - about a third of them have discoloured/wilting leaves, as shown in the picture below. Can anybody say why? Thanks

 

Too cold or too hot? Doesn't look fungal so should be OK I think. Experts will be around to put me right !!

 

I don't think it's to do with temperature - all the ones I potted the week before are in the same place and are okay.

 

It looks like sun scorch to me. Do they get the sun on the window sill Zesty? Have you watered them while the sun was on them? If there was any water on the leaves it would make them 'burn'.

 

Yeah, they do get a lot of sun. When the sun's out anyway! I have watered when the sun's on them, sometimes multiple sprayings a day. Should I put some water in the bottom of the tray and let them soak it up instead?

 

It's almost definitely sun scorch then. This happens on all plants, when there is water on the leaves it becomes like a magnifying glass when the sun is on it, therefore burns the leaves.

It would be better if you could move them out of direct sunlight, perhaps another window sill. Don't spray them anymore, it's not really necessary anyway and water the pot carefully avoiding the leaves. You could water when the sun has gone from the area for the day, but check the following morning that any water on leaves has dried before the sun returns.

 

So it's not a good idea to have these in direct sunlight then?

Also, what do you mean by don't spray them anymore? I take it I still have to water them at some point, do you mean I should start using the other method of standing the tray in some water instead?

Or is it a case of I don't have to water when the sun's out because they're not suddenly going to keel over and die?

Bonus question marks: ?????

 

Direct sunlight for seedlings and young plants can be too harsh.

Don't spray the leaves with water but water underneath the leaves into the soil. If the plants are out of direct sunlight you should only need to water once a day. Preferably evening and the heat of the day won't dry out the soil so quickly.

 

Thanks