How to Select Onion Sets

by Michelle Valenzuela

Overview

Onions are cold-weather crops that grow close to the surface. You can grow onions from plants, seeds or sets, which are also called bulbs. Using sets is the easiest way to grow all types of onions. The key is to plant them in early spring and keep them watered. Green onions planted from sets can be ready to harvest in about 30 days, while other types can take about 100 days or more to mature.

Step 1

Check with your nursery to find out when it will get onion sets. Buy them as soon as possible, before they can be exposed to warm temperatures in stores.
Step 2

Choose sets that will produce the types of onions you want to grow. If you want round onions, choose torpedo-shaped sets. For flatter onions, get round sets.
Step 3

Sort your onion sets. Sets smaller than a dime will usually produce large onions. Because sets that are bigger than a dime go to seed earlier, they are best used for green onions, which can be harvested before the plants go to seed.