I planted some D. Stramonium seedlings about 4 weeks ago. About 20 sprouted around 2 weeks ago, and as of this morning only about 6 look healthy - the rest have started flopping over and looking quite unhappy. The seedlings still have only their first pair of leaves, and have been kept indoors on a heat mat and under fluoros (with regular misting so they don't dry out). Can anyone tell me what I might be doing wrong?? Thanks, Chris.