Tip: Prune vertical roots regularly
Regularly prune the vertical roots of your bonsai. Make sure your bonsai tree has an evenly distributed, spherical and superficial root ball. This will stimulate an even sap flow through your tree and improves the development of nebari.
Tip: Contain your seedlings!
Use multiple smaller containers when you plant a bunch of seeds, instead of one bigger container. This way, you will have more control over watering conditions and positioning of your individual bonsai.