Flower garden which we started from seeds (a variety of flowers) is coming up and some seed packets said to thin when they get to a certain height. How important is this. Its outdoor in a 2'x20' plot, so its not like being crowded into pots or flats but the seedlings are coming up real thick and I don't want to start losing them. Should I thin them out. I'm afraid if I disturb the soil at this tender stage I may do more harm yhan good.