Q.growing parsley
I grew parsley from seed and when big enough I planted it out in new compost. After several weeks it is turning yellow on the outside of the plant. Would it be better to plant seeds directly into the ground?

Planting directly into compost can be problematic.
These articles will help you.
https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/planting-in-pure-compost.htm
https://www.gardeningknowhow.com/edible/herbs/parsley/tips-on-how-to-grow-parsley.htm