I sow tomato seeds in small square pots, about 10 - 15 per pot. When they have their first true leaves starting to appear I pot them on individually. I plant them so that quite a lot of the stem is buried, in the hope that roots will come from the buried stem.
However, I've found that when it's time to pot on, there are never any roots in the top part of the soil, the roots are always in the bottom part of the pot.
So, do the 'stem' roots only develop once the plants are mature and growing in their final position? If so, it would probably be better for little plants to be potted on near the top of the pot which would give more soil underneath for roots to develop.
Anyone have any thoughts on this?