they're not gonna strangle each other but they'll create a very dense mass of vegetation which impedes air movement along the bottom of the growing area. if you have situations of high relative humidities in the early part of the growing season, you are creating an environment conducive to disease proliferation. all i'm saying is that if you give a plant optimum growing conditions(within your realm), creating an environment that is as stress free as possible for the plant will lessen the problems that MAY occur further on down the road. good soil amendments, enough room to grow, light, water and such, things will progress fine. my whole being, while working in the green industry, was dealing with customers who had problems with their lawns and plants that were either self-imposed or just overlooked. the main thing i learned, and am still observing, is that if you can manage to give a plant what it needs, it will perform well for you. any hurdles you throw in front of it, will just slow it down. as you know, plants don't have legs and cannot jump hurdles! yuk, yuk! sorry, i had to work tonight, and will do the same tomorrow, so needless to say i'm enjoying a few hoppy beers. you too b-hoppy! and HAPPY HOLIDAY!