Lavender has turned brown!
I’ve planted a few lavender (hidcote) plugs into a large 30cm container, with a drainage hole, using some vermiculite at bottom then topped with multipurpose compost with John innes3, then a sprinkle of vermiculite on top and around plugs. I then watered using general plant food, then watering almost everyday. Within a few days all lavender has turned brown! Only one plug has stayed mostly green. Have I done something wrong? and how can I resurrect them? Please help