Certain things can't be sprouted in a jar with a screen lid. As you learned, flax is one. Cress and chia also have the slime.
That is why chia seeds are smeared on a piece of pottery that is kept wet (those stupid chia heads).
"Sprouting Instructions
Chia seeds cannot be sprouted using conventional tray or jar sprouters, and must be dry sprouted. There are two different approaches to dry sprouting Chia, but we recommend the terra cotta dish approach:
Our preferred method:
* Sprinkle a thin layer of Chia Seed on the bottom of a terra cotta dish or plate.
* Set the terra cotta dish in a larger plate of water.
* Cover with another plate.
* Small amounts of water permeate the terra cotta plate upon which the chia seeds sit, and provide exactly the right amount of water to sprout them.
* On the second day, lightly mist the seeds.
* Harvest on the third day.
* It takes about 2 or 3 days to get healthy Chia sprouts.
An alternate method:
* Lay a nylon or linen cloth on a plate.
* Spray a fine mist of water onto the cloth.
* Sprinkle 1 layer Chia Seed on top of the bag. Mist it lightly.
* Cover with another plate, misting lightly once per day.
* You will have Chia sprouts in about 2 to 3 days."
http://www.wheatgrasskits.com/sprouting/chia_sprouting_seed.htm
I tried sprouting cress the usual way and it was a mess. After a couple of days I just put it in some potting soil to see what would happen. It grew like crazy
