Granddaddy Purple - 2019 Grow - 1st Grow

So this week scared me, as the leaves started to turn yellow. I was told it was either over watering or nutrients in the soil. So I place them outside during the day when it was hot and sunny, which dried out the soil and 3 out of the 4 plants were laying on their sides when I got home work and the soil was very dry. I propped up the stems and gave them some pH 6.0 water around the edges. I've been putting them out when the sun is shinning, but they still seem small to me, hoping to soon leave them outside 24/7.