Starting Onion Seeds Outdoors
Sowing onion seeds outdoors can allo you to skip some transplanting steps. Here's how.
Combine the onion seed with some radish seed (about 5% radish seed) and sprinkle or "broadcast" this mixture in a wide row about 15 inches across. Don't worry too much about spacing - as you harvest the fast-growing radishes (they also serve as row markers) and young onions for early eating or pickling, you'll create plenty of space between the remaining onions for them to grow to full size.
To make sure the seed has good contact with the earth, spread a light layer of soil on top of the seed and firm it into the soil by tamping it down with a hoe or rake.
Young Plant Care
When the plants are about 1/4 inch high, thin out some of them with a steel garden rake. You may feel cruel doing this the first time, but do it. The end results will be worth it. Just drag the rake lightly through the onion row. The teeth thin out some of the plants, and also cultivate within the row, uprooting many little weeds as well.
When the bulbs reach the size of a marble or walnut (1/2 to 1/4 inch in diameter), you can pull some of them to use right away for pickling or boiling. The small white onions are best for canning, pickling and boiling. 'Crystal Wax' and 'White Portugal' are two good small white onions to grow. Sow them close together in April or May after preparing the soil as you would to grow big onions.
For storage onions, try growing 'Early Yellow Globe', a convenient, all-around cooking size. Plant the seeds fairly thickly and give the seedlings a really good thinning by dragging a rake through the row once they've sprouted. When the onions have developed a good top growth, pull up some and eat them as scallions. Your aim is to harvest enough to eat as scallions to leave the remaining plants at a spacing of three to four inches apart.
You can gain a week or more on the onion season by soaking the seeds in lukewarm water for a few hours before planting them.
Another way to sprout the seeds is to spread them on a wet paper towel and roll up the towel. Then put it on a damp terrycloth towel and roll that up. Put the towels in a plastic bag and seal it. Check it after four or five days. When the sprouts are tiny, plant them just as you would onion seeds.