Started a few WW,s that are now about 2 and half ft high and into the 2nd week of 12/12 . They get fed twice a week , 5 look pretty good but two look a bit dry , the leaves are curling up at the sides and on one the leaves have begun to get dark yellow stripes . I have followed the instructions on the bottle for the food and the ph is about 6.2 - 6.5 . The door to the outside gets opened for about 15 min everyday and I have an intact fan bringing in fresh air but at the mo no outake fan . Should I be worried ? Also no serious budding yet .