There is a point where the water sits in the lower levels of soil.

New Zealand lemonade on US897 rootstock. · More Info

I purge the extra water out of my containers.

Steve

Use transparent plastic cups and color the water appropriately to see where the water settles to. Not always easy to see though.

Recently I had presented the concept in our local bonsai club. I used a sponge and completely saturated it and then let it drain for about 5 minutes till it stopped dripping out of the bottom. The end result is this picture with 2 inches of perched water. Hope you can see it.

Perched water by definition is a continuous column of water as illustrated in the above pic. The region above is moist but not saturated like below.

I now see what Sponge Bob Square Pants looks like after being caught in a rain storm

Good one Steve.

Vlad there are indirect methods to presence and volume of detect perched water but cannot visualize it. First saturate and drain the media for about 5-10 min till it stops dripping. Then insert a wick through the bottom hole, let it hang at least 6 inches to fool/disrupt the water column. The excess water will start draining through the wick - collect it and measure it to figure out the PWT.

Thanks, guys, for your comments.

Tropic, I ma not sure what you mean by perched water being "a continuous column of water". The water content of your sponge seems to be discontinuous in that there is a sharp demarcation between the perched water and the water (moisture) above it.

The bottom saturated portion is continuous column of water filling all the pore spaces (or air spaces if you will) held against gravity - that is the definition of perched water. The line demarcating saturated and unsaturated is the boundary where gravity takes over. The height of saturated water (in this case about 2 inches) is the PW height for this sponge. I do not know how else to explain.

Assume all pots taller than wide and with adequate drainage will still have a recurring too wet zone at least as tall as the one visible inside the sponge. With containers that are shorter relative to their width than the outline of the sponge having even more of the soil volume subject to becoming saturated every time the plant is watered.

Or, you can stick a wooden stick/dowel all the way to the bottom of your pot; come back the next day, pull out the stick and you can see where the stick/dowel is most saturated..... something on the order of a car's dip-stick.

Just want to clarify, the height of the perched water is a dependent on the soil mix - some will have high value like peat based soil and some will have low value such as gritty mix. The sponge is for illustration - peat based soil with organic compost will probably have a higher PWT than the sponge I used.

Perched water is determined by the size of air spaces between particles. In a freshly prepared mix it is determined by the size and shape of the particles making up the soil. A freshly prepared gritty mix will have near zero PWT. For freshly prepared 511 mix it is no more than an inch or so.

Al I like your comment so much I gave you 3 Likes. But all I ended up doing is like, unlike, like so you only got 1 of the 3 likes from me.

Steve

You'll note I returned the favor. Thanks!

Al

Al, many thanks for you helpful post.

From the pictures posted by Al, I illustrated 'A' earlier with my sponge example. If you turn it to 45 degrees you get 'B', the height of the water is the same but the volume of water reduces. Here is the pic of the sponge illustrating 'B'. This is an easy way to get rid of some of the excess water.

Exactly, ToC. The sponge illustration is what I use to demonstrate how a PWT works whenever I talk to a group about container media. It doesn't surprise me, but it might surprise you guys to learn you could be classified as members of the 1 percenter group of container growers who realize there is such a thing as a PWT, and it's best (for the plant) to try to remedy its effects if you are dealing with a medium that supports water in excess. When I give a talk about container media, I always try to get a sense of who knows what drives water retention and how to fix things when it's off the rails. My best guess is, unless they're serious pot growers or bonsai practitioners, the number of hobby growers who have even the most basic understanding of how water retention works would be somewhere near 1 in 100.

Al

Thanks Al. Sponges it make it much easier to illustrate water retention since it is quite visible. And they come in various grades from coarse to fine that makes it even easier. A large fraction of members (mostly new members and even some old timers) in our bonsai club were actually astonished that the sponge holds water suspended in air without a pot. Makes it easier to also explain why putting pebbles for drainage will also result in exactly the same scenario.

Next time, I think, I will figure out a way to illustrate C, D and E from your figures. It will be fun to do.

I regularly add holes near the edge of the bottom of the pot to make it easier to use the tilt/shake method to get rid of the excess water.

I have most of my trees in 5 gallon buckets. I tied a rope to the handle near one side of the bucket and swung it around me to produce 3-4 G's to rid the excess water. Too much work. I now use the vacuum cleaner and a vacuum chamber under my trees to pull water out.

Steve

If you are not in a hurry just leaving the pot tilted at 45 degrees for 15-20 minutes will release most of the water. That is what I do in winter with the indoor plants. Outdoors I try to set most of my larger pots in contact with soil and that takes care of the excess water. Actually I try to dig in to the soil a few inches or more. This keeps the pots stable under windy conditions too.

Ballast. I'm going to probably further confuse people that tell me my pots are falling over outside, but perfect description. Maybe I can draw a similar diagram of my pots to illustrate what I'm doing. When I remember to do this on dryer days during our relatively brief rainy season my pots have no issues. I use rearranged big mulch pieces to get the angle. Sometimes angled down to one of the three corners on long boxes, where the overflow pipe comes out.