I use the same soil too and it's fine, but the thing is with time released nutes it will give nute burn based on how much you water. The more you water the more nutes are released so you should only water when the soil is completely dry up to a depth of about 2-3 inches. Just give them some time and don't overwater and they will be fine. I water every 3-5 days. Overwatering is the biggest mistake by new growers, just have some patience. And btw you might want to eventually transplant to 3 or 5 gallon pots because growing in a 2 gallon pot will usually result in the plant being root bound.