I believe those trays are called plug trays. You may want to try Horticultural Products and Services (HPS)if you are looking for a large quantity.
Karen

Plug trays are generally all the same size, as they fit the equipment being used to handle them. The number of plugs per tray can vary in most cases from 144 to 512. Obviously the size of the plug must also vary in size. These plug trays are not practical for home production without the equipment required to fill them and seed them. Al

International Greenhouse Company also has many different supplies. Worth checking out. :)

- Steve

I respectfully have to disagree with Al about the practicallity for home production. I have been using 72 count plug trays for years. They are not hard to fill and you can start many plants in a small area. I love using them as it doesn't take large quantities of mixture. The sources quoted above are good. Just do a Google search for plug trays and you should be able to find anything you need. Just make sure that they are good quality and not the flimsy ones.

I had never heard of a "plug tray" of less than 144 which is what my supplier lists. Larger than that he skips to "liners". A 72 plug tray would be quite usable for the proficient home propagator. Al

McConkey lists plug trays of 50, 72, 98, 105, 128, 162, 288, 400, and 512 cells per a tray, with various depths available.
They are also much cheaper than most retail online sellers.

I wouldn't call myself a proficient home propagator but I do like my 50 cell plug trays. I've got two hundred tomatoes started in one. A like number of peppers in another. Right now I have over a thousand seeds started in a space about eighteen inches by five feet....and feel like I'm wasting a lot of space that could be starting even more seeds.

californian do you have a website for McConkey? Al

Calistoga, here is a link. But they sell wholesale so you would have to buy a one case minimum unless they happened to have an open case. I buy my plastic pots from their warehouse in Garden Grove, CA, and pick them up myself at their will call, but they have other locations.

Here is a link that might be useful: McConkey growers supplies

This is there web page

Here is a link that might be useful: McConkeys

Calistoga,

I recently placed a order with the GreenhouseMegastore. They are a division of International Greenhouse Supply. Thanks for the link-Steve.

They carry smaller hobby packs (10 count) of seed starting trays and inserts. Shipping was perhaps a little pricey but I liked the option of the smaller packs.

Karen

Thanks for the references. The more sources the better. Al