The time flowering takes is strain dependent. It does look like they needed a little more time. If you are only using like a 400watt light, you don't want your plants to finish much taller than 24" or so. That is why the bottom of the plant barely has any nugs on it. There was not enough light to penetrate down that far. Flower your plants smaller, let them flower until 80% of your hairs are red, and you will have an even better plant to smoke next time.