I would like to set a 4x4 post (10 ft) in a tall, heavy plastic planter. I am using 2 50 lb bags of Quikrete. It says to just pour the concrete in, set the post, and then pour about a gallon of water in per bag. Then, directions say the water will simply saturate into the Quikrete.

I guess my question is: will the water actually reach all the way down to the bottom of the quikrete mix (maybe 10-12 inches down, at least)? if not, how much do I need to stir? And if i don't stir it vigorously, am i gonna wind up with a bunch of dry concrete mix at the bottom and properly set concrete on top?

Any help for this DIY newbie is appreciated!

  • A spade shovel and a wheelbarrow are good for hand mixing.
    – K H
    Commented Apr 17, 2021 at 3:04
  • Are you using Quikcrete "fast setting" or one of their regular? Personally, if using the 'fast setting', I'd still try to introduce some water before dumping it into the planter. (The fast set relies on ground moisture, which you aren't really going to get in a planter.) Commented Apr 17, 2021 at 14:59

1 Answer 1


When setting posts in the ground the concrete mix will absorb extra moisture from the surrounding soil. I pour some concrete mix in and stir water in.....repeat till the hole is filled. I also know of fences and 4x4 posts that were set the way you described and they are still plumb straight and strong many years later. Only reason I would say to not just pour water in on top, in your situation, is because there is nowhere for the bottom mix to get extra moisture from if needed. I would either pre-mix the concrete beforehand or mix it after you put it in the planter.

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