I haven't tried soil blocks yet.
But I'm thinking about experimenting on part of one 8x16 propagation tray. The cells are square (and tapered) and have big square ridges down each side - I assume to reduce root-circling, althoguh I've heard them called ventilation ribs.
But it means that each cell has not 4 corners, but 12, that roots ought to be channeled into.
If I made a series of holes up and down each "corner", maybe roots would be guided to those corenrs, out the holes, and dead-end due to root pruning. But it might require the "puckered", "sticking-out" hole illustrated in the ad.
If they did p[rune, and if that stimulated roots to branch, it might be A Good Thing.
