GARDENING FACT SHEET:
Click to View Printable PDF file: “Growing Onions”
When to Plant Onions
- Plant onion sets in the spring, usually mid to late April.
- Onions can take a frost, but will not tolerate a hard freeze. Mulching your bed will help keep the soil warm.
Where to Plant Onions
- Onions require a sunny location; ideally at least 8 hours of sun a day.
Soil Preparation, Fertilizer and Mulch for Onion Plants
- Prepare the soil by working some aged compost and an all-purpose fertilizer into your soil to a depth of at least 4-6 inches.
- Onion bulbs will not be able to grow in compacted soil.
- Onion sets should be planted no deeper than 1 inch below the soil line, 3-4 inches apart.
- Onions prefer moist, but not soggy, soil.
- Onions are shallow rooted, so will benefit greatly from a 1-2 inch layer of mulch.
- Onions are heavy feeders so side-dress with an all-purpose fertilizer once a month.
Harvesting and Storing Onions
- Onions are ready to harvest when their leaves are starting to turn brown, or the tops are falling over; usually mid to late August.
- Stop watering several days before harvest to allow the soil to dry out.
- Dig up the onions, and let them cure in a warm, ventilated area for about 2 weeks.
- Once the stems have fully dried, cut them off about an inch above the onion and move the onions to a cool, dark area for storage.
Click to View Printable PDF file: “Growing Onions”
