by Jeannine Anderson

Created on: May 10, 2011   Last Updated: May 11, 2011

Onions are shallow rooted plants that grow best in light loams, sandy soils high in humus or high organic matter peat or “muck” soils.  Planting onions in raised beds allows the gardener to provide the preferred type of soil condition for growing onions, even if the main garden soils don’t offer ideal conditions.  Another advantage of raised bed gardening is the ease with which weeds can be pulled and water can be regulated.

Onions do best when they receive at least an inch per week of rainwater or irrigation.  This means that enough irrigation needs to be applied to penetrate down to one inch below the surface, and you can test for this by simply poking your finger into the ground and assessing the moisture of the soil.  Onions that don’t receive the necessary amount of water can become overly spicy, even if you are growing “sweet” varieties.  The loosely worked soil of raised beds enables the gardener to easily test soil moisture, and apply adequate watering that can easily penetrate to the root area of the onions.

Because onions are shallow rooted, they can get a lot of competition from weeds, which also tend to be fairly shallow rooted.  The light soil in a raised bed makes for easy picking when it comes to weeds as their roots don’t have to sink too deep to find the water and nutrient they seek.  Regular weed maintenance, before plants are allowed to gain much size, is the best way to reduce the onion’s competition for water and nutrient from invasive plants.  Preparing your onion bed several weeks ahead of planting will give some of the weed plants time to emerge so they can be pulled even before your onion sets, or seeds, go into the bed.

Using raised beds for growing onions ensures that the gardener is able to provide the right environment for producing dense, firm onions that will develop good size and keep well.  Storage onions that are grown well, in the proper soils and with proper nutrients and irrigation, can be put away for use throughout the winter.

When onions begin to develop skins and the top leaves start to topple over, they should be pulled and allowed to cure in the sun and fresh air.  This curing process takes at least a week, sometimes longer, if the garden is in an area with high humidity or frequent light rains.  Don’t allow the onions to remain uncovered during heavy rains; move them indoors or under a covered shelter if this is the case, otherwise they will not cure properly and will not last long in storage.  Storage onions that are properly cured keep best in onion bags or shallow boxes in a cellar or pantry with near freezing temperatures and humidity between 65-70%.

Reference:

Johnny’s Select Seeds, 2011 Catalog

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