Q.Cabbage Seeds Germinate Well But Then Stop. Warmth And Water Ok
Is this due to poor soil? People say should grow in compost?

Certified GKH Gardening Expert
Most of the time, this is due to soils that remain too wet for too long. Unfortunately, your photos did not come through, so I cannot see the state of the soil and plants in question.
Seedlings need very little nutrients to get started, and starting them in compost will burn them before they even germinate fully.
Likely, it is due to infected soils from overwatering, or saturated soil from the same.
Here are some articles that will help:
https://www.gardeningknowhow.com/garden-how-to/propagation/seeds/when-to-start-seeds.htm
https://www.gardeningknowhow.com/garden-how-to/propagation/seeds/soilless-seed-mix-info.htm
https://www.gardeningknowhow.com/garden-how-to/info/using-fungicides-in-garden.htm