Plug trays - anyone using these?

Central, TX(Zone 8b)

I start herb and vegetable seeds using 50 cell packs or community pots to germinate them until I can bump them up to 4" containers for growing on.

I'm curious if anyone is using 128, 144, 288, 520 cell packs for starting seeds, if so, what seeds are started in which size cell pack? Whenever I visit greenhouse/nurseries that start their own seeds I see numerous small cell packs with hundreds of plants started this way before being bumped up. Makes sense that an individual plug can be easily lifted and popped into a larger container however placing seeds into each cell by hand will be a daunting task!

My seed starting arrangement consist of a 5 shelf metro rack equipped with 2, 4' shop light fixtures per shelf and seedling heat mats with thermostat to control bottom heat. If it's possible for me to use the same space to produce more seedlings without the hassle of "picking them out" of community pots, I'd like to give it a try. Nothing speaks like the voice of experience though - please chime in?

Oh, the web site where I saw these is:

Thanks a bunch!

Wheaton, IL(Zone 5b)

Hi Garden Sass:
I start all my seeds of annual flowers in plug trays. Think they might be the 128's. My cells measure about one inch square and about 2 inches tall. What you have to remember is to sow only one type of seed per tray, as different seeds have different germination times. Since I would not sow 128 seeds of the same variety, what I have done is cut the plug trays into smaller parts - usually 2 rows of 5 cells (single rows would not be steady). That way I can sow 10 seeds (or multiples of 10) of each variety. Also remember bottom watering is very important with the smaller cells. I just set the small plugs into a dishpan of water until I see the top surface is moist. Be sure to let them dry down though, since constantly moist soil will produce damping off and fungus gnats :( - also more of a problem with the smaller cells. You can sow 2 seeds per cell (or 3), since you won't get 100% germination, and then just snip off one seedling. My cells have a small hole in the bottom, and I use a pencil top to push out the plug when I'm ready to bump them up to a larger cell/pot.

If you use the tiniest plug trays, you will be bumping up your seedlings a few times. With the size I use, I get good root growth, and then only have to bump up once to a 4" pot. But I have only grown annual flowers, so I don't have experience with veggies, but I think it would be similar.

Hope this helps.

Central, TX(Zone 8b)

Thanks Elijablue - good pointers, especially cutting the tray into smaller units!

Everett, WA(Zone 8a)

I've used
- 128-cell prop trays (8x16),
- 72-cell six-pack-inserts (12 inserts per tray and 6 cells per insert), and
- 50-cell prop trays (5x10).

I have a few other types that I don't like as much.

I cut my 128 prop trays into segments of 3-5 rows. Just two rows tend to tip over for me, but then I'm clumsy when I lug them around. two rows of the 50-cell tray might be stable, but I get by with cutting the 10 rows up "3 - 4 - 3".

The 128-cell prop tray is only usefull to hold the seedling briefly, then I pot up to a Dixie cup or 4" square pot.
72-cell six packs can often go straight outside, and the 50-cell prop trays can go right outside..
I recntly foun d a DEEP 50-cell prop tray - I think it was 3 3/4" deep (from Steubers Distributing).

I like a very fast-draining seedling mix with screened bark nuggets and bark mulch shreds added to any commerical seedling mix. The only time I tried to bottom-water, I plugged to bathub drainpipe and needed a plumber!

I got my trays in 10-packs here, until i found a Steubers outlet within driving distance:

There are some pictures of propagation trays (plug trays) here:

These are the typical flimsy tear-able "six-pack inserts". It's easy to tear off one six-pack, flip it upside down, and flex the bottom so the root ball pops out intact.:

These are the sturdier "propagation trays".

Everett, WA(Zone 8a)

Has anyone ever used the 20-narrow-rows-per-tray things? I thought they might be good for alyssum and lobellia: sow thickly in a line, sprout to a tangled strip, pop out the whole row, then tear off 2-3 inch pieces for each pot.

"20-row seedling flat"

Everett, WA(Zone 8a)

I recntly found some super-deep, small plug cells. Each is a tall, narrow cone that fits into a holding rack.
One is explicity for starting tree seedlings.

"Cone-tainers" 1.5" diam and 5 or 8" deep

Deepots: 2.5" diam and 10" or 14" deep! For trees

They also have very small, nicely deep cheap plastic pots:
"SQV0064": 2.5" square , 3.5" deep.
32 pots for $2.80, 9 cents each

Here's a nice pictorial over-view of all kinds of gadgets:

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