Garden Tips From the Micro Farm: Growing Onions
One of the most useful parts of my garden is definitely my onion bed.Onions are used almost daily in my kitchen, and growing them is like having an onion bank in the backyard that I can visit any time that I need one.There is no need to put onions on the grocery list, and trips to the store for an emergency onion are eliminated!
I recently came into approximately 200 onion sets, thanks to my friend Steve from The Style Nursery.In red, yellow and white, all three varieties are short day onions, meaning that they will grow and make bulbs when the days are short, less than 12 hours in length, as opposed to long day onions that require at least 14 hours of sunlight daily to form bulbs.
In addition to being sensitive to day length, onions also require temperatures between 55 degrees and 75 degrees Fahrenheit to set bulbs.These optimal temperatures occur where I live in Phoenix during the winter months, when the days are short.I have in the past made the mistake of not paying attention to the day length requirements for the onions that I planted, resulting in inadvertent long day plantings that never set bulbs because the days were too short when the temperatures were right.After a season or two of disappointment, during which I blamed the heavy clay soil in my garden for the lack of bulb development, I did some research and FINALLY realized that I MUST plant short season varieties in our particular climate if I want anything more than plants of “green onion” size.
I am crossing my fingers for a bumper crop this year.
I planted onions from seed in the fall, but recent events that included the sheep escaping from the pen and rampaging through the garden, very few have survived.We also brought home a couple of puppies, one of which loves to eat onions, so I decided to replant in the front yard, away from marauding animals.It is now January, and the temperatures are too cold to grow from seed.However, the weather is perfect for setting bulbs. So I was very happy to receive onion sets, which have already grown leaves and are ready to put energy into growing bulbs.
I was not expecting to plant onions in the front yard, and so I did not save any room for them in my garden beds.A new bed needed to be built, during which time I soaked the onions in water so that they would not dry out, and to promote root growth.I also found a stick that was the same width as the bed, a useful tool for planting onions.I plant onions densely, and have always used a stick to ensure even spacing between rows.It occurred to me that the stick could make the actual planting much easier.Here’s how:
1. Starting at one end of the bed, I line up onions on top of the soil, with their greens leaning against the wall. The stick is placed in front of the onions, and a second row of sets is placed, leaning against the stick.
2. Soil is placed in the bed, covering the onions and the stick to a depth of about one inch.
3. The stick is then removed by lifting it carefully so that is raises the green onion tops out of the soil, leaving the bulbs buried.
4. The stick is placed against the planted onions and a third row of sets is leaned against it. This row is buried, and the stick is lifted, raising the onion greens. The pattern is repeated until all of the onions are planted, no need to press each onion into the soft soil individually. The rows are spaced evenly, and planting is quick!
5. I planted all 200 onions densely in a 6ft X 4ft bed and placed markers where each variety starts and ends. I will systematically pull green onions from the bed, as needed while they are growing, moving down the rows and marking where I have last harvested so that spacing remains even. Removing some of the onions for green onions makes room for the bulbs of the remaining onions to grow larger in size.
The size of an onion bulb is a reflection of the number and size of the green leaves at bulb maturity. For each leaf that is growing on top, there will be a ring of onion; the larger the leaf, the larger the ring size.
Besides providing proper spacing between onions, large bulb growth can be encouraged by adding phosphorous to the soil at planting, followed by additions of nitrogen every three weeks until the onion stalk grows soft, signaling that harvest is just a few weeks away.
Onions are mature and ready to be harvested when their tops have fallen over. Allow pulled onions to dry, clipping the roots and the tops back to one inch. To preserve them, handle them carefully to prevent bruising, and keep them cool, dry and separated. Onions wrapped separately in paper or foil can be preserved in the refrigerated or cold storage for as long as a year. Aromatic or pungent onions will store longer than a sweeter onion varieties. Onions that have bolted, or flowered, do not store well, so use them quickly.