Onion Seeds - Red Long of Tropea

Minimum Seeds per Packet: 200

Packet Weight: 1g

Planting Season: Spring or Fall

Sowing Method: Direct Seed or Transplant

Seed Depth: 1/2"

Direct Seed Spacing: 1"

Soil Temperature: 50-95 ℉

Days to Sprout: 6-16

Mature Spacing: 3-6"

Sun Requirement: Full Sun

Frost Tolerance: Frost Tolerant

Days to Harvest: 90

When to Seed Onions 

Onion seeds should be started eight to ten weeks before your last frost date. They can be transplanted outdoors once they reach pencil thickness. For varieties that overwinter well, you can direct seed them in early fall. 

Where to Plant Onions

Onions need plenty of sun in order to mature and bulb up. Choose a spot with well-draining soil that is rich in organic matter. 

Growing Onions

Most growers will start onions indoors and transplant them out in mid-spring. Onions do best in cool temperatures, but a little afternoon shade can help them to take some summer heat. Most varieties are somewhat frost tolerant, but none of them will tolerate long periods of below-freezing temperatures. Some type of season extension, like row cover or a cold frame, is a must for growers who want to overwinter their onions. Sow onion seeds ½ inch deep and one inch apart either if direct seeding or in holeless flats. Keep the soil moist but not soggy until germination. Onion seedlings are particularly sensitive to damping off so you’ll want to make sure they’re getting good air circulation. When you’re ready to transplant, gently separate your onion starts and plant them out (or thin them) at their mature planting distance of three to six inches. 

Harvesting Onions

Around the expected harvest date for your particular variety, check the bulbs for maturity regularly. Harvest once the bulbs size up and a skin has formed. Some varieties are also great harvested before the full mature stage for “baby” onions. These should be eaten quickly because they won’t keep like storage onions will!

Onions (Allium cepa) are biennial, meaning they flower in their second year after overwintering. If you live in an area where the ground freezes, you will need to dig up the plants you want to save seed from and bring them inside somewhere with temperatures between 40 and 50 degrees F, then plant them back out once the ground thaws. If the ground doesn’t freeze where you live, just cover your onions with row cover for the winter. They will send up flower stalks as the weather warms up in spring. Onions are insect-pollinated, so they need to be separated from other Allium cepa varieties by at least 800 feet in order to save pure seed. If you can’t be sure they are isolated by distance, you can place bags over the blossoms to prevent insects from reaching them, and hand pollinate by moving pollen from one flower to another with a paintbrush. Once the flower heads have turned brown, and black seeds are visible within, clip the heads and shake the seeds out into a container. Make sure the seeds are completely dry before storing in an airtight container in a dark, dry location. Onion seeds typically don’t remain viable more than 1-2 years, so use your seeds soon!