But still dig them up to look at them so you can select for the best ones. Using only perfect roots will give you the best chance for a strong crop. There's such poetry in the culmination of the cycle, the innate desire to procreate and the bridge from one generation to the next. I think we should celebrate when a plant goes to seed, and be ever vigil to reap the rewards of a plant in its last hurrah. There are basically two types of seed, wet seed and dry seed.
Most biennials are dry seed.
Dry seed is either enclosed in a pod or is exposed. Examples of seeds in pods are bean, kale, and pea. Examples of exposed seeds are spinach, parsley, carrot and lettuce. If you hear the seeds rattling inside they are usually ripe for picking. Dump the seed into a container from the vents or shell them out of the pods.