Basil loves hot. Back usually indicates that its under stress due to recent rooting. If you cut off leaves and chop them, they also turn very dark. A soilless mixture may be a bit too 'clean' for it too, as compared to a potting soil. Suggest that it gets repotted again, and try to remove some of the soilless mix, and replace it with regular potting mix.

Thanks for your help. I'll do it tomorrow.

Mine, too! I went out this morning to patrol the plants and all my basil has developed black spots on their leaves. They are in various containers and in raised beds. Could it be from the rain we have had (the ground is still wet from the downpours earlier this week)? They are mature plants, so I can't see how it could be a root establishment issue.

I bought a new basil plant and it was beautiful, but now the leaves are turning black. I need some help to identify the problem. I have had many basil plants, but never this problem. What is wrong and what can I do for it? Thanks for the help. Please reply to my e-mail: rossmz@commspeed.net

Needs sun and a little less watering.