My basil is yellow

Question

It’s inside

Answer 1

Basil needs sunlight for the process of greening of the leaves. It also requires soil fertility with adequate nutrients for healthy green growth.

If your basil is inside and not in a window area where it can get several hours of sunlight each day, you may need to consider a grow light, and fertilization.

https://www.gardeningknowhow.com/edible/herbs/basil/yellow-leaves-on-basil.htm