How Do You Set Onion Planting Dates?
You should always think ahead when planting a garden. It’s important that you set your onion planting date early enough to give the onions a chance to develop but not so early that they freeze. If you plan ahead and are methodical about setting your planting date, you improve your chances at having a fantastic crop of onions. Consider where you are planting. If you are in a warmer region (such as in USDA hardiness zones 8 and 9), you can get away with planting the onions in the autumn. If you are in a region with cold, frosty winters, look up the last frost date. Mark your calendar five to eight weeks before this last frost date as the optimal time to plant the seeds or sets. (Onions seeds will produce the better onions. Onion sets are tiny, dried second-year onion bulbs that will develop into big onions.) Mark your calendar 10 weeks before the last frost date as well, because that is when you can start onion seeds inside. You can then transplant them after six to eight weeks.
