A great way to view and understand your building or repair project before you get started. If you only dig a foot or so and pour some concrete the first or second winter the earth will literaly spit out your fence posts and knock them down. Then add your proposed fence outline, heights, distances from property lines and gate locations. Debris can offset measurements and placement of the bike bollards; Moisture can damage the integrity of the post.
Give the concrete some time to dry and harden before building the fence or putting any weight on the post. Drilled a 24” diameter holes 6 feet deep, poured a concrete base inside the hole 12” thick, stood the post up, and filled the holes with pee gravel. The part of the wood that was buried two feet down and only partially covered with concrete is still in excellent structural condition.
Be sure to have sufficient rebar cut to length, as well as anchor bolts or post bases on hand, as they must be added to the concrete while it is still wet. It is recommended that gravel be laid at the bottom of the hole to keep moisture away from the bottom of the inserted post. If you have soil that does not percolate well like clay, you are better off doing concrete. Not mentioned yet: you can make the concrete anchor slightly bigger than the 4×4 post. Your fence posts are not going to fall over with this method, but you will never know until a problem surfaces. You say concrete will perform” better if mixed properly or some such balderdash.
Deck footing & pier construction guide: this article explains how to prepare deck footings or piers using cardboard tubes, reinforcing steel, post connectors, and concrete. You may want to use a QUIK-TUBE Building Form QUIK-TUBEs are rigid fiber forms for setting posts for projects like deck piers, patio footers, dock pilings, heavier fence post bases, etc.
Makes a lot of sense if the post were used for a fence, but what if the post was expected to experience frequent downward, and sideways pressures. I pushed the post base in the concrete at an angle and worked it in to consolidate the concrete around the base. Steel verses wood… It would always be advisable to go for the longer distance, more durable steel over wood applications.