Yes this could be a big problem !!! But it might not be that bad . If it is just at the bottom its probally just the sun leaves giving the flowers the nutes they need. The bottom leaves are really no prob. They need to come off anyways to let light to come in to the lower flowers. If It starts to happen all the up thats when you should really freak out.. Like hazey said to ph is very important so you should always keep up with that. A very cheap tool to save you alot of money... Good luck my friend.