Just remember that when you purchase a put instead of a futures contract, you have no margin liability and enjoy all potential profits if the price rises further (through your insurance).   If you enter into the futures contract, and the price rises $2 per bushel for example at anytime between now and december, you will have to put up $2 cash margin x number of bushels contracted.

If you buy puts on a day the market jumps up you usually can buy them for less premium.