Here's a product that could help.
http://www.antistress.com/ASMan6.html
Also maybe put 4 stakes around the seedlings and cover with a shade cloth.
Ensure right soil and mulch conditions.
In my experience of hot dry summers in Adelaide, it was those hot windy days that did the damage. Around seedlings the shade cloth will break that wind down to.
Shade clothe comes in different %'s of blockout, 90% down to 50% around here. Scale it over the years so the seedlings adjust, 1st year maybe an 80%, second year 50%.