Many of my onions are blossoming or going to seed, preventing a bulb from forming. Is there a way to prevent this?
This means they have bolted. These article can help: https://www.gardeningknowhow.com/edible/vegetables/onion/find-how-to-grow-onions-in-your-garden.htm
https://www.gardeningknowhow.com/edible/vegetables/onion/onion-info-tips-for-growing-big-onions.htm
https://www.gardeningknowhow.com/edible/vegetables/vgen/what-is-bolting-what-it-means-when-a-plant-bolts.htm
When do you pick the seed pods from the onion tops?
Once the tops have gone to seed, you can remove and store them until ready for planting.
Can you plant onions next to lettuce?
I have been looking for a seller of onion sets. Scallion or spring onions. I have not been able to find a retail seller of these products. Can you be of any assistance?
Perhaps a search for local farmer's markets can help. Most garden centers also sell scallions.
While we do not sell scallions, we can provide information on how to grow them. These articles will help: https://www.gardeningknowhow.com/edible/vegetables/onion/growing-scallions.htm
https://www.gardeningknowhow.com/edible/vegetables/onion/harvesting-scallions.htm
Someone gave me the biggest and sweetest onion ever, two pounds easy. What am I doing wrong with mine?
The key to onions is soil. They need very rich soil. Have your soil tested and amend as needed to grow big and sweet onions.
I planted my red onions from bulbs on Mother's day (May 8th), but now the stalks are 12 to 14 inches tall and getting yellow buds on the end of some of them. What should I do?
These are just flower buds. Many people just cut them off so that the onions focus their energy on the bulbs. Here is some information to help you keep them from flowering in the future:
https://www.gardeningknowhow.com/edible/vegetables/onion/onion-bolting.htm
I want to grow big onions, if possible, and this year's weather in New York seems good for them. My problem is the stems are about 18 inches tall and they are starting to seed, but the bulb isn't very big yet. Can I cut the stems back to prevent this without bothering the growth?
The following articles should be of some help to you:
https://www.gardeningknowhow.com/edible/vegetables/onion/onion-info-tips-for-growing-big-onions.htm
https://www.gardeningknowhow.com/edible/vegetables/vgen/what-is-bolting-what-it-means-when-a-plant-bolts.htm