My seedlings have been in toilet paper rolls for about 3 1/2 weeks. One roll unraveled on me, but the other 15 still seem sturdy. The roots of some are starting to grow out the bottoms. I'll keep you posted.
I actually just did a project with my after school group where we planted veggie seeds in t.p. roll pots. We looked at the little stickers on fruit from the grocery store and then looked at a map to see how far it has to travel to get to us. The girls got REALLY into planting the seeds. Hopefully, the pots hold up long enough for them to get them in the ground.
My local greenhouse business sold me flats with cells for a $1 each. Each flat of cells holds 4 doz. seedlings. I also purchased the potting soil that they use on their plants at $15 a big bag. Expensive, yes, but very light and loamy and went a long, long way.
With potting cells that cheap and which can be re-used next year, I find them to be the best starter pots for seedlings. Can all those greenhouses be wrong?
With the proper care, these plastic cells should last me a good long time and will pay for themselves over and over again down the years.