What could be causing this?

Outside grow 10 gallon fabric pot. TIPS just started this the other day? It has been extremely hot and sunny. Missed one day of watering pretty dry this am when I went, nothing was wilting, missing a day of water could have guessed this or do I need to add something? Feeding light dose of fertilizer. Thanks in advance.

You water those tiny plants everyday?

It's just one plant about 6 foot tall. And usually every other day as the pot dries out so fast. But I went 3 days and missed a day.