I may be doing a fence and i am doing the deck this summer so this question is critical. Do you need sono tubes or could you just put concrete in a hole. My worry is that if i make the hole tapered the frost could grab the top and ruin all my work. Also the frost line here is 48" and sonotubes come in 8' lengths, i fell like i need to extend the concrete above the ground a few inches and this would leave me with a unusable 40+" length. How do you guys do it:whistling