Things you stumble across - soil blocks

[ysengrin]

Soil block makers are hand-operated presses that make a compacted soil cube. You start seeds directly in the cube of compressed soil; no container is necessary. Since the cubes' sides are in contact with air, roots will stop growing when they reach the side of the block. Contrast that with seedlings grown in the typical retail greenhouse's flimsy plastic tray, in which the roots wrap around the space between the soil and plastic, becoming pot-bound.

From Cool Tools; links from that article to several resources.