Yellow leaves while flowering

My plants are flowering now. The leaves are turning yellow. Is there something wrong or missing. Growing in a green house.

When your plants transition from veg stage to flowering stage then they need more potassium and phosphorous. You need to add bloom nutes to your base nutes. Even with the bloom nutes your plants will start to yellow on the bottom fan leaves. This is normal. Your plant is using the stored sugars to get through the flowering stage.
I hope this helps :sunglasses::us: