My pumpkin starts are doing weird things. They only have 3 or 4 leaves, but have several flower buds... the leaves on most plants are starting to turn yellow and shrivel. None of that seems like it should be normal? I have them living in my greenhouse, it gets up to about 35 in there some days, and down to around 8 at night (celsius) humidity fluctuates between 30% and 60% and I have been watering them well every day. I don't see any bugs or obvious signs of disease... should i be doing something differently?