Onion
Although onions take at least 6 months to
mature, they can be planted out thickly and used as shallots from the
half-grown stage onwards. Thin them out progressively until the
remaining plants are 7-10 cm apart and leave these to mature.
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Requirements to Grow Onion
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A well-drained limey soil in an open
sunny position because partly shaded plants tend to turn to seed.
Prepare soil as suggested for cabbages. Compost or animal manure should
be dug in a couple of weeks before sowing or planting, otherwise they
tend to attract onion flies.
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Planting time for Growing Onion
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Sow or transplant into double rows 15 cm
apart. If more than 2 rows are sown, allow 20-25 cm between each set of
rows. Scatter the seeds thinly along the rows and when the young
seedlings emerge from the hooked-over stage, thin out to about 2 cm
apart.
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Seedlings may be planted at the same
spacing then, from the time they each lead pencil thickness, thin and
use as shallots until about 10 cm apart, then leave remainder to
mature.
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Salad onions can be improved by watering
every 3-4 weeks with a complete water-soluble plant food.
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This treatment is not recommended for
keeping types as the extra nitrogen reduces both keeping qualities and
strength of flavor.
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When transplanting seedlings they will be
easier to handle and will establish better if the tips are trimmed to
half-length and the roots to about 4 cm.
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Cultivation for Onion
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Sow direct, spacing a pinch of 2-3 seeds
about every 10 cm along the row, then thin to the strongest one in each
spacing. If growing only 2 rows space only 15 cm apart. Once the
seedlings have established, water fortnightly with complete
water-soluble fertilizer.
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Special problems in Growing Onion
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Shriveling of the leaf tips can be due to
downy mildew which is controlled by spraying with Zineb or Mancozeb.
Leaf tip shriveling accompanied by a white streakiness of the remaining
foliage is usually due to attack by onion thrips. These pests develop
resistance to chemicals so it is better to alternate sprays, using
Thiodan or Carbaryl one week and Malathion or Lebaycid the next.
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