Onions are a common garden plant that grow year-round in most frost free areas. Plant red and yellow onions varieties using the same method with either a dry or green onion transplant. Verify the number of days it takes the variety of onion you are planting to reach a mature harvest size before planting, which ranges from 50 to 150 days depending on the type of transplant. A little planning guarantees you will have fresh onions available when you want them.
Prepare the soil six months before planting by spreading 3 inches of composted manure over the area. Work the compost into the soil with a tiller and smooth the area with a rake. Let the soil rest until the desired planting date.
Dig 1-inch-deep planting rows with a shovel. Place the onion bulbs 4 inches apart along the row with the sprout side facing upward. Back fill soil that was removed from the row and lightly pack it around the bulbs to hold them in place. Set the rows 24 inches apart to provide walking access for harvest.
Apply a nitrogen-based vegetable fertilizer to the soil around the onion bulbs three weeks after planting to promote strong growth. Dampen the soil with water after the fertilizer application to assist with absorption. Repeat the fertilizer application every three week until the neck on the onion bulb softens, about one month before harvest.
Provide supplemental water to the onions when the weekly rainfall is less than 1 inch of water per week. Attempt to keep the soil evenly moist without creating standing water around the onions. Well-hydrated onions tend to have a sweeter taste.
Things You Will Need
- Composted manure
- Nitrogen-based vegetable fertilizer
- Plant ground cover vegetables, such as tomatoes, zucchini, cucumbers or herbs, in the prepared onion planting area during the six month rest after amending the soil.
- Choose manure that has composted for a minimum of one year for best results with planting onions.
- Plant short-day varieties in late fall and early winter and long-day varieties in early spring and summer for best results.
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