so basically i have a set up with 400w high pressure sodium light. my humidity is usually between 39 and 50% temp between 69F and 84F the ph of my water is 7 and the soil has nutrients in it to sustain the plant for the first few weeks which i am currently in. the plant are at the stage of the their fourth set of leaves forming ant they are about 12in tall with the light a further 15in from them. the big leaves are turning yellow and curled up as they look to be drying out at the ends. ANY IDEAS ANYONE????????????