My tomatoes survived 5 sunny days without watering thanks to my tray-in-tray solution. They were just dipped in water all the time. When I came yesterday it was high time to refill the water. I noticed also that their roots were hanging below the tray bottom like some seaweed. It happened because they had grown very long during those 5 days and went out through holes that are in the bottom the the tray. I pulled them up carefully and put all the roots in the cubes tray. Some of roots ends broke and I hope it did not cause shock to the plants and does not affect their growth. So far they look strong.
I am impressed how fast seeds sprout in the propagation cubes and how fast roots grow. It happens much faster than in a regular soil. On the other hand though the whole process needs too much attention. Growing plants in regular pots with soil maybe is not so effective and it takes longer time for seeds to sprout but they really need only regular watering (not too often).
Now I try to keep the water level not too high so it only reaches the bottom of the tray. The cubes absorb water very well so they stay moist.
Long roots of the plants
Tomatoes one month after sowing
Next step will be transplanting my tomatoes to bigger pots. I am looking forward to doing it.