I have two basil plants in containers on my back patio. I thought I did a good job layering the dirt on little pebbles and watering enough. Recently my first basil plant (sharing a container with cilantro) is barely producing, it's just not growing. I am cutting but nothing. So I got a larger container full of basil that was more mature and it's been great! Up until this heat wave, the stems have been turning woody and brown (not the leaves) and during the day the leaves look limp and pathetic and evenings they perk up a little but it hasn't been producing much recently. What am I doing wrong?