Why are my buds so small

Why are my buds so small? Currently week 8 of flower. Hydroponic dwc buckets were flushed once a week. Nutrients were added once a week. Ph was set to 6.2 once a week. I'm using a 400 watt hps light on a 12 12 cycle. I added 2x75 watt equivalent bulbs on the sides two days ago.

Picture with my thumb is the main cola

Because they need more time

Nick is correct. Those don’t look like their in week 8. But either way they’re no where close and should fill out.

Bud size depends a lot on strain, all else equal. Plants that stack calyx vertically like yours don't get as plump, just the way it is. I agree that you have a long ways to go still. Quality is what matters most, not size. There are some very popular strains that yield terribly relative to others.

Thank you for the replies, I will definitely keep them growing out longer. It's just the plant the right behind the one in question is budding up fine.

The strain is s.a.d. f1 for those interested