How to manage Welsh onions in summer? A full breakdown of the key techniques
How should Welsh onions be managed in summer? Please advise. Welsh onions prefer a cool, moist environment, with an optimum growing temperature of 15-25°C; above 26°C, growth becomes thin and slow, and above 30°C they enter a semi-dormant state. The first stage generally runs from planting the onions to the start of the dog days, a period when the temperature rises from 15°C to 25°C, which is relatively...
How should Welsh onions be managed in summer? Please advise.
Welsh onions prefer a cool, moist environment, with an optimum growing temperature of 15-25°C; above 26°C, growth becomes thin and slow, and above 30°C they enter a semi-dormant state. The first stage generally runs from planting the onions to the start of the dog days, a period when the temperature rises from 15°C to 25°C,
which is relatively suitable for Welsh onion growth. So after planting and recovering from transplanting, they quickly enter the first growth peak, producing one leaf every 4-5 days. At this time, strong seedlings should be selected, planting should be done early, and fertilizer and water management should be strengthened. The second stage runs from mid-July, when the dog days begin, to early August, when the dog days end, right in the hot summer. At this time Welsh onions grow slowly, producing one leaf only every 8-10 days, their disease resistance weakens, and they enter a semi-dormant period, so cultivation and weeding should be strengthened, with attention to drainage and pest and disease control. The third stage runs from mid-August, at the end of the dog days, to mid-October; temperatures drop, the day-night temperature difference widens, and Welsh onion growth speeds up, producing one leaf every 3-4 days, with the white stalks elongating and thickening rapidly, entering the second growth peak. At this time, fertilizer should be applied promptly and cultivation and earthing up strengthened to promote white stalk growth and increase yield.
The main diseases of Welsh onions are purple blotch, downy mildew, and rust. Purple blotch and downy mildew are mainly controlled by spraying the leaves with chlorothalonil, metalaxyl, or oxadixyl after rain. Rust appears as small brown raised spots on the onion leaf surface,
and should be controlled by promptly spraying triadimefon after rain.
The main insect pests of Welsh onions are root maggots, leafminers, and onion thrips. To prevent root maggots, spray trichlorfon once every 10-12 days after the Start of Autumn, which has a good repellent effect on adults; after they appear, drench with a 90% trichlorfon 800-1000 times dilution. Leafminers and onion thrips
can be controlled by spraying the leaves with dimethoate, cyhalothrin, or imidacloprid.
Onion leaves have a waxy powder layer, so no matter what pesticide is sprayed, 1% neutral laundry powder must be added to the spray solution as a spreader so that the pesticide can adhere to the leaf surface and take effect; otherwise the spraying will be ineffective.
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