Propagation: Park's Biodome: Anyone tried it?, 1 by RickCorey_WA

RickCorey_WA wrote:
>> It was a combination of pine bark, chicken grit (fine granite) and Turface.

Nice! Now the root hairs in that mix will never drown or suffocate! Nice drainage and aeration!

I have 8 mknths of rain per year, and heavy, heavy clay with almost no "perk". I obses about drainage and waterlogging even indoors.

>> are you using this mix in a Parks bio-dome or a homemade one ?

Homemade in the sense that I use 4-5 generic plastic "1020" trays to catch the runoff water,
2 plastic humidity domes or a bunch of 18" wide "Saran Wrap" or 'food film' to retain humidity,
some cotton flannel as a capillary wicking sheet,
and a spray bottle and mustard bottle and ketsup bottle to water gently.

The only part of the Bio-Dome system that I really wish i had were the extra-deep cells.
I try to compensate by using a capilary mat to draw excess water out of each cell: to fight the dread "perched water" that alwyas used to drown my roots when I overwatered.

I still overwater, but now more of my seedlings survive. My goal is to make a seed mix that drains as fast as i can over-water.

I put my bark-grit-perlite-whatever mix into "propagation trays", also called "cells" or "plugs".
Or I use "6-packs" also called tear-apart plastic inserts.

When I have to pot up before planting out, I used to use 2 sizes of Dixie cups (Solo cups), but they tend to fall over.
Now I use 3.5" square plastic pots, much lower than Dixie cups and wider.

I am still experimenting, but I tend to use plug trays with 50, 98 or 128 cells.
When using the "inserts", I usually use the trays that hold 72 cells (12 packs of 6 cells each).
You see that I start seeds in pretty small cells.

>> I ask because I would like to know what you do to try and keep the plug together when you pull it out of its container

I use the small cells so that they approach being root-bound pretty fast.
The roots themselves hold the soil mix together if the root ball is healthy.
Other than that, I try to support the soil ball from three sides with my hand or a fork with bent times and one time cut off.

Then I rest the soil ball on a clean 'Sharphooter' spade and slide it into a prepared hole as gently as I can (squatting and kneeling are two things I can't do if I wnat to get up again without help).

Pine bark can be pretty fibrous if you have not removed all the fines, and that TENDS to hold together if the roots help it somewhat.

But 90% of my answer is: I let them get almost root-bound in a very small cell.

My biggest cell (the 50-cell prop tray) is 1" across at the bottom, less than 2" at the top (round-conical 2.4" deep).
I don;t use the 98-cell tray any more becuase they are only 1.5" deep (round, 1.4" at the top and 1" at the bottom).

I don;t have the ones I use most handy to measure, but the 72-cell 6-pack (inverted Vee) is pretty common, for vegetables or fast-starting things like Zinnias or marigolds.

I use the tiny 128-cell prop tray for small perennials like salvia, and petunias. Small slow-growing things that I wnat to give every possible chance to become root-bound so i don;t tear the root ball to shreds.