I use a variety of containers, milk jugs, 2L, and 4" containers. The four inch containers are placed in a large plastic box with holes in the lid and bottom for rain and for drainage or the large plastic box is slipped into a large plastic bagwith slits for moisture and drainage.

i don't have any trouble with 2L bottles standing on their own. If concerned try placing 2Ls in between two rows of milk jugs.

Gallon milk jugs work best since the wind blows through my breezeway which is where I set the containers. I use patio blocks/bricks to keep them from getting tossed around when the wind kicks up. My neighbor goes to the town landfill every Monday so if I ask, he'll bring me the milk jugs. When I WS the first time (2007?), he howled with laughter at the idea. He wasn't laughing once they started sprouting. The pear & apple trees I grew from seed he asked me to WS for him are now taller than he is.

After years of having pots of numerous different sizes, shapes, I ordered 1000 4inch square pots. The uniformity has been a pleasure, (I also bought 1000 labels),and is the most economical use of space. Compared to trays (flats), the water retention is much better and siting the pots butted up against each other has offered extra root protection and insulation. Also, plants seem to like being grown right next to each other. Using a cold greenhouse or the protection of brick walls, I have not needed to maintain separate little biodomes...in fact, the milk jug/semi-closed container has always been the most bothersome and worrying method for me..

I use 16 0z. Styrofoam cups placed into a large milk crate. I have a picture but can't seem to upload it for some reason. It works great.

All year long I save my quart milk jugs and 3 and 2 liter soda bottles. I ask friends with large families to save me their gallon milk and water jugs, too. These containers are easy to cut and hold up well for two seasons.

jensyen--do you have trouble keeping soda bottle upright? I do.

I use small transparent plastic cups and medium ziplocs with expandable bottoms. You can disinfect and reuse them several times if protected from direct sun. The ziplocs are a bit more of a hassle to clean, so I normally buy more instead. I don't waste too many since several cups can be placed in each ziploc (4~5). For seedlings I use potting mix and for cuttings pure peat moss. I've had great results!

I use mostly gallon jugs. Really like 3 and 2 liter soda bottles but do not have access to many of these.