Onions Flashcards
1
Q
What are the temperature preferences of onions?
A
- 13-24C
- Many are frost tolerant and can overwinter outside
- There are two main types, autumn and spring.
2
Q
Explain the soil and site selection for onions.
A
- Open, sunny site
- Well-drained, fertile soil
- Prepare well in advance, digging over and incorporating plenty of well-rotted organic matter
- Do not like freshly manured ground
- Low nitrogen requirements.
3
Q
What are the two times for sowing and harvesting onions?
A
- Spring sown are harvest in late summer (take 12-18 weeks to mature)
- Autumn sown are planted in late summer or early autumn, overwinter outside, and take up to 42 weeks to mature.
4
Q
Explain sowing of onion seeds.
A
- Secondary cultivation of soil two weeks before sowing
- V-shaped drill, 13mm deep
- Rows 30cm apart
- Once germinated, thin to 5cm apart.
5
Q
What are onion sets?
A
Specially raised small onions ready for planting out.
6
Q
What are the advantages and disadvantages of onions from sets and seeds?
A
Sets
- Mature before those from seed
- More resistant to mildew and onion fly
- Tend to bolt
- More expensive than seeds.
Seeds
- Take longer to mature than sets
- More susceptible to mildew and onion fly
- Less likely to bolt
- More cultivars to choose from
- Cheaper option than sets.
7
Q
Explain sowing spring-sown onions from sets.
A
- Plant sets in well-prepared seedbed in April
- Place so nose is just above ground
- Space sets 30cm apart
- Cover with mesh to avoid birds pulling them up
- Weed regularly.
8
Q
Explain the harvesting of onions
A
- Onions can be harvested at any time once they’re ready.
- If you’re storing them, let the foliage die down naturally.
- Spring sown onions keep better than autumn sown ones.
- Once ripened, lift and dry for storing (plait or place in single layers in wooden boxes and store in a dry shed).
9
Q
Name a pest and a disease of onions, including symptoms and control methods.
A
Onion Fly
- White burrowing larvae eats bulbs
- Yellowing leaves, tunnels in bulbs, death of plant
- Place collars around plants in May and August; Grow sets instead of seeds; Destroy infected plants; Grow resistant cultivars; fleecing.
Onion White Rot
- Fungal disease that can last in soil for 15 years
- Plants suddenly die, leaves yellow, roots rot off; white cottony-looking fungal growth with black poppy seed-like sclerotia at base and sides of bulb
- Grow from sets rather than seeds; buy from reputable source; use long rotation and avoid infected ground for at least 8 years; grow resistant cultivars; good hygiene.
10
Q
Name:
- 2 autumn seed onions
- 2 autumn sets
- 2 spring seed onions
- 2 spring sets
A
Autumn Seeds
- ‘Senshu Yellow’
- ‘Keepwell’ F1
Autumn Sets
- ‘Radar’
- ‘Autumn Gold Improved’
Spring Seeds
- ‘Caribo’
- ‘Red Baron’
Spring Sets
- ‘Sturton’
- ‘Stuttgarter Giant’.