I have a bean tower I purchased from Garden Supply that fits into an 18 inch pot that I want to grow pole beans on. Am wondering how many seeds to plant? I just want to be able to harvest enough at one time to cook for dinner for three people. I was thinking to put two or three seeds at the base of each vertical arm of the tower (8). Just wondering if you think this will overcrowd the pot and/or if I should plant more or fewer?