Because the side of a pot, especially a pot made of porous material, is more or less continuous, it has a lot of potential for water molecules to adhere to the pot wall. Since there is more adhesion at the interface between the pot wall and particles vs the amount of adhesion between soil particles, you would expect a greater tendency for there to be a very thin film of water on the pot walls that is slightly higher than the PWT say 1/8" inside of the pot wall. Even soils that aren't capable of supporting a PWT can support this light film of water on pot walls.

I suppose that, technically, you could call the water that remains as a microscopic film on soil particles and water that is retained in the immediate interface where soil particles contact each other perched water, but that's not water we're concerned with. We're concerned with the water that fills potential air spaces between particles because the size of the particles is small enough to increase adhesion to beyond the point where water will defy gravity and remain in the smaller soil pores instead of the pores draining.

Example, if you have a container of a given volume filled with 100 1" diameter balls, the balls would have 314 sq in of surface area for water to stick to. If you had 1,000 1/10" balls, the surface area increases to 502 sq in, but 1,000 1/10" balls wouldn't come nearly as close to filling the container because of the reduction in pore size.

I have to admit that I can't recall how to determine how many of the smaller balls it would take to fill the pot, but it would be considerably more than 1,000, which would significantly increase the surface area and in doing so increase o/a adhesive forces.

You can thwart the sum of adhesion and cohesion causing perched water, and even force waters tendency to be retained at the interface where soils touch by employing Newton's First Law of Motion. Hold the pot with perched water and a drain hole over the sink and start moving it up and down. You'll find that each time you reverse directions from moving downward to moving upward, a good measure of perched water exits the drain hole. You'll soon learn that a gentle downward rhythm followed by a very sharp reversal upward will fling your plants against the ceiling, so unbridled enthusiasts should try this maneuver when they are about to fall asleep. Actually, the sharp reversal upward is the most effective way to force water from pots. It works great for small plants, and there's no mess involved unless you try it on the couch while watching your favorite TV show.

Summed: The water you asked after isn't the 'bad' water. Water that remains in potential air spaces between soil particles is the water that limits root health and function.

Al

In a perfect world, all your soil particles would be slightly larger than .100" (1/10), because that's the demarcation between soils that will/won't hold perched water. At that particle size, you maximize good water retention but still eliminate a perched water table.

A kid's paintbrush is good thinking. I use them to 'paint'' weed killer on stubborn weeds that pop up from time to time in bonsai pots, the ones that have roots that break off and from which the weed regrows when you try to pull it out, but they'll serve very well for the repotting chore of making sure air pockets are eliminated from the soil surrounding roots.

Tip: when using any variation of a chopstick or wood dowel to settle soil around the roots, if you push the tool into the fresh soil, then rotate it so the part you're gripping sort of moves like it's following the rim of a funnel or so the top of the stick moves like a hurricane (Sorry, Florida. I hope everyone is ok.) while the point in the soil stays relatively stationary, you'll be able to actually watch the soil disappear into the funnel-shaped hole you're making. It'll be somewhat reminiscent of the whirlpool that almost got ol' Odysseus.

Did you know that early man would burn goosefoot and use the ashes as a salt substitute?

Al

Hi Al, no I did not know that, but I am not a bit surprised that you did;). So, right, I just spent most of the day doing that whirly thing with my recently repotted plants, and it is ridiculously fun. What a great tip!! It's remarkably effective for getting the mix settled at a super-fine level.

I liked it so much that I tried it with several random household utensils. When I realized I was doing it with knife I use to stir my coffee, I realized that I had gone too far. Also, to anticipate your question, I use a knife to stir my coffee because a spoon won't fit through the hole of my thermos. My dad suggested that I make it in a mug and then pour it in the thermos, and I told him to mind his own business.

I also got out my ruler and marked of 1/10 of an inch just for future reference. It is about the size of a wire basket I purchased to sift 511 mix, so tomorrow there's going to be some serious sifting going on.

btw, you haven't by chance run into a conversation between Jamila and I over on the "show your philodendrens" thread? If not, don't. If so, it's jamila's fault.

Just throw me under the bus why don't you!!!! LOL.

Lol!!!! I wondered if you would see that!! ROTFL!

Sorry, Jamila lol!

Yup I caught you!!! LOL

If your father ever does something like that again, I'd get a new one. I fired mine when I was about 24 yrs old. At our family business, there was a 'swear jar'. Every time we got caught swearing, a dollar had to go in the jar. Since my dad was also participating in the penance, I thought, "What a cool dad", and figured at some point, the money would be put toward something that involved us all. When I discovered he was taking the money at the end of every month and taking my mom out for a nice steak ........ that was it for me.

Cute story: When I married my wife, she had 2 very young boys. They wanted to pick out their own Father's Day cards for their bio dad, so I took them to the drug store. After what seemed like a very long time I asked the youngest, "What's the matter, Kent? Can't you find a good card for your dad"? He said, "No, I'm looking for one with money in it."

Now I'm curious about the Philo thread, but L said I can't go look. I prolly won't sleep tonight for wondering what the heck's in it.

Al

Ha! That is a cute story:). My dad gets his walking papers about once a month for giving unsolicited advice. But then when I realize he's always right, I rehire him again;).

you can look at the thread if you want, but just remember: we are blaming all things on Jamila. She's totally ok with this.

Al, I made my first gritty mix today. It took a while to get the plant jump started, but now, it's as happy as can be. The difference is immediate and profound.

I'm gonna send you a picture.

Yup just blame me!!!