Sapling Tray and failed Capsicum plant

This is the simple sapling tray that came along with the Tamilnadu government rooftop garden kit.
The above photo shows the well grown saplings of Capsicum. I tried it as an experiment, not knowing whether these plant will grow in harsh Chennai summer.
The seeds i used are directly taken from a Capsicum which i bought for cooking.
As a 2 inch height sapling i re-planted them in a bigger coco-peat bag.
After 7 days, when it was showing signs of stability and all of a sudden within a span of 2 days almost 8 (all of them) saplings wilted and died. :-(

Now, no Capsicum is left and i'll try again after June end.
I'll love to make Capsicum Chutney with my fresh Capsicum from my rooftop garden.