Onion

Onions are grouped by day length. Short-day types bulb with ~10–12 hours of daylight and suit the South and Gulf Coast. Intermediate-day need ~12–14 hours for bulbing and thrive in mid-latitudes. Long-day require ~14–16 hours and perform best in the North. Generally, sweeter short-day types store briefly; pungent long-day types store longest.

• Short-Day (South): Plant in fall or winter for spring harvest as the onions begin bulbing when days reach 10–12 hours of daylight.

• Intermediate-Day (Middle): Plant in early spring as bulbing begins with 12–14 hours of daylight.

• Long-Day (North): Plant in spring for summer harvest as bulbing begins with 14–16 hours of daylight.

Soil Requirements:

Adjust soil pH between 6.0–6.5

Rich in compost or organic matter

Loose, well-drained soil. Heavy soil will put pressure on the bulbs as its developing and could inhibit growth.

Fertilizer Schedule:

Before Planting:
Mix 1½ cups of HOSS Complete Organic Fertilizer per 10 ft of row

2-3 Weeks After Transplanting:
Sidedress with 2 cups of HOSS All-In-One (10-10-10) per 10-15 ft row.

If using Fertilizer injector, 1 cup 20-20-20 Fertilizer and 1-2 cups microboost per 20 ft row.

3-4 Weeks after transplanting:
Sidedress with 2 cups of Ammonium Sulfate per 10-15 ft row.

6-8 Weeks after planting:
Sidedress with 2 cups of HOSS All-In-One (10-10-10) per 10-15 ft row.

If using Fertilizer injector, 1 cup 20-20-20 Fertilizer and 1-2 cups microboost per 20 ft row.

10-12 Weeks after planting:
Sidedress with 2 cups of Calcium Nitrate Fertilizer per 10-15 ft row.

If using Fertilizer injector, 1 cup Calcium Nitrate Fertilizer and 1-2 cups microboost per 20 ft row.

30 Days Before Harvest:
Stop All Fertilization.

Harvest: You need to stop watering your onion plants 1-2 weeks before you begin harvesting and curing them. It is time to harvest or pull up your onion plants when 50-80% of the tops start falling over. Check your weather to make sure you have at least 2-4 days with no rain. After 2-4 days gently shake off the dirt from the roots without bruising the bulb. It is usually best to harvest in the morning when it is sunny and temperature is between 75-80°F.

Curing: Once your onions have cured in the field for 2-4 days it is time to move them to a curing location that needs 3 factors. Good ventilation, shaded from direct sunlight, and space that is 75-80°F. While the onions are curing, the skin will constrict and become dry around the bulbs. The necks of the plant will also turn brown and brittle and have no moisture present. A good rule of thumb is if you’re not sure if the onions are ready, give them a little more time to cure before storing them. On average it takes 3-6 for onions to completely cure and become ready to store.

Storage: Sweet onions: Best eaten fresh, typically last 1–2 months. Stronger, pungent onions: Cure and store well for 3–6 months in a cool, dry place.

• Storage Life: Cure and store properly—long-day onions can last up to a year, while sweeter short-day onions keep 4–6 months.

• Natural Pest Deterrent: Plant onions along garden borders to help repel deer and rabbits; they also pair well with lettuce, tomatoes, beets, and strawberries.

• Maximize Yields: Plant closer (3") and thin early for a bonus crop of green onions before bulbs mature.

• Smart Storage: Keep onions and potatoes separate to prevent premature rotting from ethylene gas.