>> Bob has drilled the holes too large and I have made shims out of old chopsticks or popsicle sticks or sticks from the yard and wrapped them with duct tape.!!!
Since you're using duct tape already, you might be able to make one-piece shims from 2 liter soda bottles taped inverted into the hole in the milk jug.
P.S. Duct tape may last 1-2 seasons, but Gorilla Tape is forever!
Kitazawa Seeds is great, and they EXPLAIN what each variety is and give recipies.
http://www.kitazawaseed.com/
I also like Tainong Seeds: they mainly sell wholesale to commercial growers, but will sell 2-gram pkts for $2 to anyone, and Priority S&H is only $5-$6. Two grams is a lot of Brassica seeds!
Tainong has pictures and a brief blurb for each variety. They have nearly as much variety as Kitazawa, but lean towards commercial growers hence have many hybrids and popular OP varieties (not rare heirlooms).
http://www.tainongseeds.com/
If you would like to try any I have, or swap for a sample of HORENZO, Akarenso or 'Vitamin Green", here's my Asian & Brassicas Have List:
http://cubits.org/ellasgarden/...
Bok Choy green stem & white stem,
flowering Bok Choy (Yu Choy & Yu Choy Sum),
Gai Lan,
Tatsoi,
Mustard,
small Gaichoy
Mizuna