My onions have gone to flower. What can I do now? They are beautiful flowers, but I cannot help thinking that it is not good for the onions! Should I harvest them now? Some are a good size but most are small. Will they keep? What is the best way to keep them?
Members of the onion family are prone to bolting. Here is an article or two that you may find helpful: https://www.gardeningknowhow.com/edible/vegetables/vgen/what-is-bolting-what-it-means-when-a-plant-bolts.htm
Most people do cut the flower off because it will sap energy away from making the onion bulb. But, if you would like to have seeds to collect and grow, you can leave it on. If you want to collect the seeds, you do need to let the seed pod dry before collecting the seeds.
This article can help with storing suggestions: https://www.gardeningknowhow.com/edible/vegetables/onion/storing-onions.htm