Some things to think about for the future.
- Get clones acclimated before transplanting. Meaning let them put their toes in the water before jumping in, especially if clones have been kept under lights and inside. Give them a few days to a week outside before transplanting. - Watering times could prevent leaf burn during the heat of the summer and try to water from the base. - Planting time could prevent heat exhaustion, plant early or late in the day. - You don't want to expose roots to the sun, so being efficient when planting is good. - Tickle or loosen roots, to get them ready to expand. - Sometimes after transplanting its good to be cautious but again plants will naturally stress out during a change of environment. Changing the soil, pH, water times, and light cycle will cause stress. This can be seen most notably by purpling stems. Typically they will snap out of it within 2-3 weeks. - Getting to know deficiencies and excesses is important but I think you were a victim of the heat. Here is a cheat sheet but taking some time to read will be your biggest time and money saver in the future. Here is the link to cheat sheet. https://www.alchimiaweb.com/blogen/marijuana-growing-guide/nutrient-deficiencies-and-excesses-in-cannabis/