The plants of different varieties can and do respond differently to different weather and environments.

The temperatures you state and being in sun all the time are not good at all for any seedlings. As far as that goes, when the plants get larger with those temps and humidity it's going to be difficult for the plants to even set fruit and you'd probably see a lot of blossom drop as well.

For now I think if it were me I'd put those 7 week old seedlings in only partial sun for just a couple of hours.

Do you expect those conditions as to temps and humidity to be the same in the future and if so for how long?

No, it's isn't normal for Box Car Willie to develop leathery leaves. It's a variety that I introduced by first listing it in the SSE YEarbook many years ago so I know it well. The high temps and rain are no doubt a problem and the plant is very stressed and is reacting in that way,

Hope that helps.

Carolyn

Thanks Carolyn!

It gets slightly cooler in November and December during our rainy season. I'll follow your suggestion and put the seedlings in an area with some morning sun and shade for the rest of the day. It's sometimes breezy out in the garden too, so hopefully it helps with the temperature.

Hopefully I can salvage the seedlings as they have been growing well right up till last week!