Yellow onion: Sowing, planting and harvest calendar
How do you sow yellow onions outdoors?
Sow your yellow onions outdoors in spring when the soil warms up and becomes workable. Choose a sunny position and prepare a fine, weed-free, well-drained seedbed, without fresh manure. Adjust the timing to your climate and the seed packet instructions.
Sow thinly about 1–1.5 cm deep, in rows 20–30 cm apart. Cover with fine soil, firm gently and water without dislodging the seeds. Keep the surface moist until germination, without soaking it. Thin progressively to leave about 10 cm between plants intended to form large bulbs: final spacing is not a compulsory distance between individual seeds.
Weed by hand near young plants to protect the shallow roots. Water during dry spells while they are growing. Direct-sown plants can stay in place; transplanting is not needed to enlarge the bulbs. For a storage crop, let them mature before drying them.
How do you plant yellow onions?
Plant your yellow onions in sun, in loose, well-drained soil when it is workable. Spring suits most spring-planting sets; only plant in autumn with varieties intended for overwintering in your climate. Avoid frozen or waterlogged soil. Adjust feeding to the soil, without fresh manure or excess nitrogen.
Place sets pointed end up and press them in lightly, with the tip just visible at soil level. Leave about 10 cm between them and 20–30 cm between rows. Do not cover the bulbs with an extra layer of soil or earth them up.
If you have sown under cover, harden off the young plants and transplant them into the outdoor bed. Spread their roots and plant shallowly, without burying the base of the leaves; replant pot-grown plants at their original depth. Water to help them establish, then according to the weather. Weed gently near the roots; mulch can reduce weeds, but does not guarantee protection against disease.
How to care for this plant
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Weed
Remove weeds around young bulbs, especially if they shade them. Close to the plants, weed by hand to protect the roots and avoid damaging the bulbs.
How do you harvest yellow onions?
Harvest your yellow onions when the leaves turn yellow and fall over naturally, usually in summer or early autumn depending on variety and planting date. Autumn-planted varieties may ripen earlier. Do not bend the leaves to force ripening. In dry weather, loosen bulbs with a fork if the ground is firm, without bruising them or pulling hard on the tops.
Dry them in a single, airy layer, outdoors if the weather stays dry or under ventilated cover if it rains. Wait until the necks and outer skins are dry: a few days may not be enough. Cut the foliage only after drying and leave a few centimetres of dry neck, without cutting into the bulb.
Store only healthy, thoroughly dried bulbs in nets or on slatted trays, somewhere cool, dry and frost-free with good airflow. Storage life depends on variety and conditions; well-prepared storage varieties can keep for several months. Use injured or bolted bulbs promptly, discard rotten ones and check your stored crop regularly.
Yellow onion
- Type : Vegetables
- Subtype : Bulb vegetables
- Botanical Family : Liliaceae
Characteristics
- Lifecycle : Annual
- Exposure : Full Sun
- Frost Hardiness : Frost Resistant
- Cultivation Difficulty : Easy
- Mature height : 30 cm
Sowing & Planting
- Greenhouse Growing : Not Required
- Sowing Depth : 2 cm
- Plant Spacing : 10 cm
- Row Spacing : 20 cm
Maintenance
- Maintenance : Low
- Water Requirements : Moderate
Other characteristics
- Soil Type : Humus-rich
- Soil pH Preference : Neutral
- Pest Sensitivity : Moderate
- Disease Sensitivity : Moderate
- Weed Sensitivity : Moderate
- Pollination : Insect-pollinated
- Propagation : Sowing