Need a location, but the boxwood basil is probably one of the Lesbos basils. Here in South Texas we get Downy mildew at the drop of a sprinkle. The only way I can raise it is to plant it 1/2" above the surrounding soil, and allow it to dry out between waterings. You also need to start harvesting it more-it doesn't get very tall or large,
to the forum and site. Basils have long taproots- they need their toes to stick deep down in their pot. I would probably have used a soil that had less shredded wood, and they love heat, but afternoon shade. Is this indoors? where are you located?