Some Alisa Craig heirloom onions I grew from the garden.
Photo By Erin Nelson
Have you ever grown onions and wondered why they don’t look like the ones in the grocery store? Perhaps they were small or didn’t store well. Maybe they all went to seed and ended up with pithy or hard centers. These are all things that can be fixed with proper culture and growing techniques!
Choose the right onion for this area!
Onions come in many different sizes, shapes and colors, but successful growing can depend on the variety you purchase. Onions are light sensitive, and because of this, they are divided up into three basic categories: Long Day, Short Day, and Day Neutral.
- Long Day onions are best for the Northern States (or 37-47 degrees latitude) and, therefore, the best for the Deer Park, Washington area. Long Day onions require fourteen to fifteen hours of daylight to produce nice fat bulbs. Anything less than that, and the bulbs stop growing. This is also why starting your onions early in the year is essential. These onions can produce some of the largest bulbs and are the best for storage. We are also blessed because our soil is low in sulfur, growing sweeter onions such as Walla Walla, Alisa Craig, and Wethersfield Red.
- The Southern States (25-35 degrees latitude) have summers that are too hot to grow onions. So those folks grow onions in the winter and need onion varieties that will bulb in the shorter daylight hours. Hence Short Day onions they produce in only 11 hours of light. You would think that Short Day onions would do well here in Washington State, but these onions want less light. More than 11 hours of sunlight results in small, stunted onions.
- Day Neutral onions can produce a bulb with as little as 12 hours and as much as 14 hours of daylight. These onions can produce some of the sweetest varieties, but their high sugar content makes them poor contenders for extended storage. Candy and Red Candy Apple top the list for Day Neutral Onions.
Planting your Onions
Onions are bi-annual or produce flowers and seeds in the second year. I do not recommend dried onion sets. These were grown the previous year and want to flower before making a nice large bulb. Consider growing your onions by seed instead.
Take advantage of the lengthening daylight hours by planting the seeds early. I like to start mine indoors under lights in late January, but direct planting in the ground in early April is fine too. Plant by sprinkling seeds over moist potting soil. Onion babies like friends, so having a few in each pot is good. Cover the seeds with only a ¼ inch of potting soil and gently water them. Using grow lights directly over the soil prevents stretched and weakened growth.
It’s time to plant your seedlings in the ground when the soil is workable and not a mucky mess anymore. Generally, around the same time, dandelions start to grow. Pull the seedlings apart and plant them so each bulb will have room to grow to its full size, about eight inches apart. If space is an issue for you, plant them closer together, then consume every other bulb as they start to grow.
Water well in the morning so water evaporates by night. Cold and wet nights can cause onions to rot with bacterial and fungal infections that may not be noticeable until they mush in storage. Composting in the spring or even the previous fall is the best way to fertilize your onions. Organic fertilizer can be used too, but use these in early spring so the vegetable can best utilize the nutrients. Keep the weeds down with leave mulch. Once bulbs are 3 inches across, encourage even more significant bulb growth by using a method called ‘spooning’ to spoon or scoop soil away from the sides of the bulb. Lastly, continuously rotate your onion crop with a non-tuberous vegetable every two to three years. This will help keep the soil at its healthiest and therefore less disease to the plants.