Tips from the Potting Bench

“If you hear an onion ring, answer it.”

Onions! Easy to grow and indispensable in the kitchen and the medicine chest. Onions! What would the world’s cuisine be without them?  Onions!  Their use dates back over 7000 years, the ancient Egyptians worshiped them believing their spherical shape and concentric rings represent eternal life. Onions!

We are just finishing the last of the storage onions from last summer’s harvest and the overwintered onions are looking good. In the mean time it’s time to get them in for this year. There are two ways to go about it. You can buy sets, those little dried up bulbs, or you can grow from seed or transplants. Sets are produced from seed sowed too thickly so they grow stunted. They are easy to plant but honestly I have never had any luck with them, they always tend to bolt on me. It wasn’t until I tried growing from seed that I finally got a great crop of onions. I think they are hardier, they grow better and they store better than set grown.

There are many varieties available in many colors, each with a different level of pungency. The more pungent the onion the better it is for you. Historically, onions have been used and are still used in different parts of the world today to treat colds, coughs, asthma, bacterial infections and bronchial spasms. They are reputed to lower blood pressure and retard tumor growth and have anti-clotting properties.

In addition to color and pungency onions are classified as long, short or day-neutral length types. This refers to the length of daylight needed to initiate bulb formation. To get the largest bulbs possible it is best to grow varieties that match your day length. Day length is determined by the latitude where you live and can be roughly explained this way. Anything above 40 degrees is considered long day, bulb initiation takes place when the days reach 15 hours or more in length. Below 40 degrees is short day and bulb initiation begins once the day length reaches 9 or 10 hours. Remember, the closer you get to the equator the shorter the day light gets, until you’re at the equator and then there is always 12 hours of light and 12 hours of dark. Day neutral types are triggered when daylight is 12 or 13 hours. We are somewhere around 40 degrees so it’s best to grow day neutral varieties here.

Onions need similar conditions as garlic, loose rich, fertile soil that drains well. If your soil is like ours, rocky and hard, it’s a good idea to make raised beds. It doesn’t have to be very tall, 6 inches will do it. Add well-rotted manure or compost and turn it in well. We plant using the wide bed method. Each of our beds are 3 feet wide, this allows us to plant the onions on a grid 4 to 6 inches apart in the row and between the rows. The pathways between the beds are 2 to 3 feet wide. We have learned that cramming things in to get more planted doesn’t always work out. It’s really nice to have the space to walk down the rows with a wheelbarrow or bucket and not be stepping on plants. It also gives you enough room to weed without it being a nightmare.

We like to apply a good organic fertilizer that has high phosphorous, that is the second number in the NPK ratio. Phosphorous is needed for good root development so having enough especially at the time of bulb initiation really helps the bulbs size up. Nitrogen is important in the early growth stages when you are looking for fast and abundant growth of the green leaves. The number and size of the leaves at the time of bulb initiation determines the size of the bulb. Remember the leaves are photosynthesizing or making food that is stored as sugar in the bulb, so the more photosynthesizing the more food and the larger the storage unit, the bulb, is needed.

If you plant from sets use the same spacing, 4-6 inches in the row and push the set into the ground pointy side up until the tip is about an inch or two below the level of the soil. If planting from transplants poke a hole in the soil and set the plant down in it just covering over the white part of the plant. They don’t look like much and they seem pretty fragile but they do really well. It’s always a good idea to mulch as you plant. I have been using straw but it can be hard to get in between the plants without covering them over. I put the straw through a leaf shredder one year and that worked well but it was time consuming. Now a day I like to use rice hulls. We fill a bucket with them and walk down the row placing handfuls between the plants and spreading them around so that they are about 2 inches thick. Keep them well watered until the necks start to soften and fall over then stop watering until harvest. Withholding water these last few weeks will help the plants mature quicker and helps them store longer.

The fall planted onions will be ready sometime in May or early June and the early spring planted onions will be ready sometime in August. In the between times when we run out of one and the next haven’t come on we use Egyptian Walking Onions. These are perennial onions that are always available in the garden. All parts are edible too. These too are easy to grow and delicious, they are a bit more pungent though. When you plant these think about where to put them since they will live there for many, many years. Sets can be purchased on-line; we have plants her at the nursery as well. We space them 12 inches apart as they form clumps like shallots so need a bit more space.