i am collecting tires to plant potatoes in next spring. I have read up on them and if done right you are supposed to get around 50# per 4 tire stack. there is alot of info on the net and you-tube. My objective is 4 stacks each being different except 2 which will be plain ole russets the other 2 will be Yukon golds and a red variety. the idea is vertical garden to save in ground space.