I'm thinking of declaring war on perched water in small seed-starting cells. Usually seed-starting mix starts out being mostly milled peat. Even if I add coarse Perlite or very coarse sand (very fine gravel), or replace most of the peat with shredded pine bark fiber, it seems that a little seed-starting cell, only 2-3 inches deep, is the container most vulnerable to perched water.
i'm thinking of trays of inserts (72 cells per tray) or "plug trays" with 50, 98 or 128 cells.
The usdual depth is 2.25 inches! Sometimes they are only 1.75" deep!
There's a few rare sizes that are 3.25 or 3.5" deep, say at 18 cells per tray!
And seedling roots must be among the roots most vulnerable to poor aeration, hypoxia or anerobic "drowned" conditions.
So now I'm thinking "wicks".
What small pot could drain better than one that has a big fat wick running through it, top to bottom?
And bottom watering would be a no-brainer if the wick ran right down into the water, and up through the whole soil column.
Eventually I'll go to a craft store and look for yarn or felt or woven fabric that's as water-wicking as possible. Rayon? Polyester? Any suggestions for what kind of yarn, fabric or "rope" would wick best? If it is a fabric, I'll have to cut long strips and fasten them together somehow. But if I wind up having to use fabric, the "bottom wick" or "runs the length of the tray wick" might be replaced b y a sheet of fabric, like a cheapo capillary mat.
If only short lengths of wick are needed, I'll check out "floppy mop heads" at Home Depot and maybe cut those strips in half length-wise.
At first I thought it would be very tedious and annoying to try to thread hundreds of short lengths of wick through the tiny holes in cells, and keep them from falling out before I could set the tray back down to fill it with soil. And how to prop them up while I filled 98 or 128 cells with seedling mix?
Then I thought about weaving a serpentine pattern, with long lengths of yarn, from one cell to the next, up one cell and down the next.
Then use one strand along the bottom of the tray lengthwise, outside the cells, to connect the individual wicks from each six-pack together.
Then, after watering, tilting the tray so that the "lengthwise" wick has some "drop" to it, the better to drain water out of individual wicks, and hence out of the perched water table in each individual cell. Once water dripped from the wicks into a corner of the tray, I could suck it out with a turkey baster.
(I wonder, if I ran the wicks together and then up 2 inches over the lip of a tray, if water would wick UP, and then back down to a container on the floor?)
And, appealing strongly to the "clumsy" in me, when each 6-pack is ready to transplant or "pot up", I could cut the wicks along the bottom of each cell, and cut where they loop from coming up one cell's side to go down the next cell's side.
Then the wicks would serve as handles to let me tug gently on each root ball, to pop it out of the cell! A root ball handle.
My second question (other than "is this just a crazy and pointless idea?") is, to remove perched water, does a wick really need to extend up into the soil? Or would it be just as effective to run the wick along the bottom of each cell only?
One kind of plug tray I would like to "wick" already has two holes in each cell. I could run one long wick along five or ten cells, just weaving in and out of each cell but laying flat along the bottom of each cell. I would still connect those so that one wick would run the length of the tray, to getthe maximum "wick drop" per amount of "tilt" to the tray. (Capilary flow still flows downhill more readily than horizontally, and to "pull" on perched water, I think the wick needs to drop a few inches.)
(But then it would not serve as a "handle" to pull each root ball out of its cell.)
I suppose "well drained seedling mix" would another way to solve the perched water problem, but as soon as I tested my "serpentine pattern" and "root ball puller" concepts with waxed twine, I knew that I just HAD to give this a "Mr. Wizard / Mad Scientist" try.
And I seem not yet to have mastered the "mix that drains so well, that water comes right out every time you water".