R2113 3.1 - 3.4 Vegetable crop production Flashcards
Quality and yield influences?
Base dressing
Top dressing
Thinning
Weed control
Support
Irrigation
P & D control
What are base dressings?
- Added before crop sown/transplanted
- Ideally done about one month before but can be raked in just before sowing/transplanting if soil is moist
Apply about one third of the crop’s total nutrient requirements as a base dressing and the remainder as a top dressing.
What are top dressings?
- Added to soil surface around the base of growing plants
- Foliar feeds
- Useful in correcting deficiencies
- Nitrogen frequently required as a top dressing. This is because nitrates are lost over the winter through leaching by rain. Therefore they must be applied in the spring to avoid being leached out by the spring.
- Nitrogen important for leafy crops. Can also be provided by fertilisers such as ammonium sulphate
Apply about one third of the crop’s total nutrient requirements as a base dressing and the remainder as a top dressing.
Veg with high nitrogen requirements?
Very high – cabbage
High – potatoes, beetroot, spinach
Amounts of ammonium sulphate needed: 110g/m2
Veg with medium nitrogen requirements?
Onions, parsnips, broad beans, lettuce, calabrese, turnips, French beans
Veg with low nitrogen requirements?
Carrots, radishes
Amounts of ammonium sulphate needed: 12g/m2
Watering for leafy veg?
- Frequent watering
- The most critical time between 10 and 3 weeks before maturity
- 22 litres/m2 in a single application
- Watering during dry conditions at 11 litres/m2 each week
Watering for fruiting veg?
- Critical watering time for fruiting vegetables is at flowering times when fruit is setting and swelling
- Watering during dry conditions at 11 litres/m2 each week
- Overwatering before this period will result in excess leafy growth and smaller fruits
Watering for root veg?
- A steady supply of water for steady growth
- In dry conditions water at 5 litres/m2 per week; increasing to 20 litres/m2 when the roots are swelling
Runner beans: site and soil?
- Half hardy, require a warm position to aid insect pollination
- Deep, fertile soil as the plants have deep roots
- Traditional method is to dig trenches in the autumn and fill them with manure
Runner beans: digging a trench
- Mark out with line and dig trench 90cm wide and 60cm deep.
- Loosen soil at base with a fork.
- Scatter well rotted manure or home-made compost into the trench and mix with soil from trench. Return improved soil to the trench. Add pelleted chicken manure at recommended rate.
- Leave soil to settle for at least 2 weeks before planting. Soil can be pre-warmed with cloches 4 weeks prior to sowing.
Runner beans: how and when to sow?
Cultivar: ‘White Lady’ AGM
- Station sow in situ from mid-May until July, 5cm deep, two seeds to a 2.4m bamboo cane, spaced 15cm apart; thin to one seedling per cane.
- Require temperature of 12°C to germinate
- Or start April/May under cover with modules (one seed per module, 5cm deep), hardened off and transplanted outside in late May/early June
- Protected cropping can be used
Runner beans: how and when to harvest?
- July–Oct (first frost)
- Pick regularly to maintain crop (when pods 15–20 cm)
Runner beans: how to support?
2.4m canes, sloping inwards for picking in rows or set using wigwams, crossed and firmly tied to cross members at the top
Runner beans: how to store?
- Storage – not applicable.
- Eat when picked, store for up to a week in fridge or blanch and freeze
Runner beans:
pest and diseases – symptoms and controls?
Slugs and snails:
- Symptoms:*
- Bite marks, yellowed edges to leaves and slime trails
- Controls:*
- Clear debris around individual plants that could harbour slugs
- Place gritty material around plant to deter
- Slug traps
- Hand picking
- Biological control with Phasmarhabditis hemaphrodita
Bean halo blight (a bacterial disease):
Symptoms:
- Small angular spots on leaves, changing from water-soaked appearance to a bright-yellow halo
- Leaves may die and yield reduced
Controls:
- Pick off affected leaves
- Avoid overwatering as this spreads the bacteria that causes it.
- Use seed from reputable source and do not save seed from affected crop as infection normally comes from infected seed, initially
Brassicas: site and soil?
- A fertile soil is needed
- Very high nitrogen requirement
- If using crop rotation, it is a good idea to plant brassicas after a crop of legumes or a green manure crop. Base and top dressings can also improve crop yields.
- Ground needs to be prepared well in advance to allow the ground to consolidate. A firm bed for transplanting is essential (wind rock). Earthing up is sometimes needed to provide extra stability.
- Brassicas either sown in seed beds or raised in modules
Winter cabbage: how and when to sow and transplant?
Cultivar: ‘Tundra’ F1 (AGM) (Winter Savoy)
- May – June [RHS: Apr – May]: sow in drills 1 cm (0.5in) deep leaving 20cm between rows; [RHS: sow to final planting positions, 30 – 45cm]
- Hoe regularly between rows
- Thin to 7.5cm when at least three true leaves. Spacing varies but in general compact cultivars should eventually be spaced 30cm apart and larger ones 45cm apart.
- Firm in and water
- Can also be sown in modules in cold frame – no heat needed
- Transplant the young plants 45cm apart, with 45cm between each row
- Transplant as above
Winter cabbage: how and when to harvest?
- Harvest when the hearts feel firm
- Cut as required with length of stem intact
- Oct – Spring
- The F1 Hybrids selections will all be ready to harvest at the same time
Winter cabbage: how to store?
- Cool conditions
- In cool cellar or shed, hung in nets or on racks
- Will stand in ground until required
Winter cabbage: pests and diseases?
Cabbage white (large white) butterfly:
Symptoms:
- Caterpillars of large white butterfly are yellow and black, hairy and up to 40mm long. Feed mainly on outer leaves
- Caterpillars of small white butterfly are green and feed mainly on hearts
- Holes in leaves
- Poo from caterpillars
Controls:
- A naturally occurring bacterium, Bacillus thuringiensis, kills only caterpillars and not the predatory insects, and is very effective when sprayed thoroughly above and below leaves
- Picking off by hand
- Enviromesh, to prevent butterflies from laying eggs
Clubroot:
Symptoms:
- Distorted, swollen roots and stunted growth with purple-tinted foliage, decreased yield
- Favours high temperatures, high soil moisture and acid soils
Controls:
- Rotation can help but…
- Lime the soil to bring the pH of the soil up to alkaline range (inhibits spore activity)
- Raise plants indoors in modules
- Control weeds since Capsella bursa-pastoris can be host
- Avoid compost made from infected brassicas
- Only buy from reputable source
Brussel sprouts: sowing and transplanting?
Cultivar: ‘Cronus’
Sow Feb – April, in trays in cold frame or earlier under glass at a depth of 1–1.5cm to encourage good tap roots. The seeds can also be sown outdoors in early spring in a prepared seed bed. They are sown thinly in drills 1cm deep and 15–30cm apart.
Transplant April – June:
- Transplant indoor module-grown plants in mid/late spring and outdoor-grown plants from mid spring to early summer
- The transplants should be approximately 10–15cm tall and have between 5–7 leaves
- Plant deeply up to the first pair of true leaves at a spacing of 60–75cm between the plants and between the rows and firm in well. A collar can be placed around the neck of the transplants to prevent cabbage root fly damage.
- Transplants should be watered in after planting.
Brussel sprouts: how and when to harvest?
- Sept – Feb
- Pick sprouts from bottom up
Brussel sprouts: how to support?
Can be prone to wind rock so earthing up and staking important
Brussel sprouts: how to store?
- Need cool conditions once picked
- Keep well if whole stalks are harvested
Brussel sprouts: pests and diseases?
As for winter cabbage:
Cabbage white (large white) butterfly:
Symptoms:
- Caterpillars of large white butterfly are yellow and black, hairy and up to 40mm long. Feed mainly on outer leaves
- Caterpillars of small white butterfly are green and feed mainly on hearts
- Holes in leaves
- Poo from caterpillars
Controls:
- A naturally occurring bacterium, Bacillus thuringiensis, kills only caterpillars and not the predatory insects, and is very effective when sprayed thoroughly above and below leaves
- Picking off by hand
- Enviromesh, to prevent butterflies from laying eggs
Clubroot:
Symptoms:
- Distorted, swollen roots and stunted growth with purple-tinted foliage, decreased yield
- Favours high temperatures, high soil moisture and acid soils
Controls:
- Rotation can help but…
- Lime the soil to bring the pH of the soil up to alkaline range (inhibits spore activity)
- Raise plants indoors in modules
- Control weeds since Capsella bursa-pastoris can be host
- Avoid compost made from infected brassicas
- Only buy from reputable source
Carrots: how and when to sow?
Cultivar: ‘Nantes’ (Early, 9 weeks), ‘Autumn King’ (Main crop, 11 weeks). RHS: Carrots are ready about 12–16 weeks after sowing.
- Sow Feb –July thinly in drills – depth of 1cm, 30cm between drills (RHS: 15–30cm)
- Thin once large enough to handle; final spacing 10cm, 5cm for baby carrots (RHS: 5–7.5cm final spacing)
- Hand weeding required until leafy growth is large enough to suppress weeds
Carrots: pests and diseases?
Carrot root fly:
- The carrot fly larvae and pupae over-winter in the soil and in any roots left in the ground. The black adults emerge in May to June and the females lay eggs in the soil near the carrots or other hosts. See https://pireco.eu/en/spring-2018/monitoring-and-controling-carrot-fly/
- After a week the eggs hatch and larvae start to do damage by feeding on roots.
- A month later the larvae pupate in soil to produce the second generation of adults in August to September. These again feed on the roots, causing damage in winter months, before they pupate and start the cycle again.
- Symptoms:*
- In early summer, reddening of the leaves. Later, cream larvae up to 10mm can be seen tunnelling in roots.
- Control measures:*
- Resistant cultivars – ‘Flyaway’, ‘Resistafly’
- Horticultural fleece or Enviromesh to prevent female laying eggs; raised beds (flies don’t fly)
- Clear plot well of roots in winter
- Dig to expose pupae
- Delay sowing until late May/early June to avoid first generation (and crop before Aug to avoid the second)
- Intercrop – plant carrots between rows of onions to deter fly
- Garlic spray (to confuse pest)
- Sow thinly to avoid the smell released when thinned
Sclerotina rot (fungus):
Symptoms:
Affects carrots in store. Roots are attacked near crown by infection from soil or base of leaves. Covered with white threads of fungus and rot.
Control measures:
- No roots that show symptoms should be stored
- Good ventilation will discourage development of fungus
Onions: pests and diseases
Onion fly:
Symptoms:
- Leaves wilt and young plants collapse
- Maggots can be seen tunnelling in base of bulbs
Control measures:
- Grow under fine nets
- Lift and destroy affected plants
- Plant sets as these are less likely to be attacked by first generation.
Onion white rot:
Symptoms:
- Leaves turn yellow/black
- White fluffy mould appears at base of bulbs with small black round bodies developing later. This is the resting stage which enables it to persist in the soil.
Control measures:
- Rotation of crops can help but this is limited as can persist for up to 8 years in the soil
- Remove & dispose of affected crops
Beetroot: pests and diseases
Beet leaf miner:
- Symptoms:*
- A white maggot causing large brown areas on leaves
- Control measures:*
- Remove affected leaves or crush maggot inside
- If minor, it causes little damage to the roots so may be left
Downy mildew:
- Symptoms:*
- Discoloured areas on upper leaf surfaces & fuzzy grey fungal growth in lower leaf surfaces
- Control measures:*
- Remove infected leaves & dispose
- Improve air circulation
- Control weeds
Radish: pests and diseases
Lettuce root aphids:
- Symptoms:*
- Older plants suddenly wilt and die back, usually in mid- to late summer (may see as they feed on the honeydew that the aphids produce)
- Control measures:*
- Damage is worse in dry conditions, so keep lettuces well watered
- Carefully dig them up, wash off the aphids and replant in fresh compost
- Pull up and destroy affected plants
- Cover lettuces with insect-proof mesh (such as Enviromesh) from June until August, to prevent aphids getting to the roots
- Plant resistant cv
Flea beetle:
- Symptoms:*
- Small round holes in leaves of seedlings. If attack severe, growth is stunted and seedlings killed.
- Control measures:*
- Cover with Enviromesh
- Sow seed in modules indoors and transplant
- Provide good growing conditions with adequate moisture
- Grow plants under horticultural fleece and keep the soil moist. Water in nitrogen-rich fertilser to help the crop outgrow the pest. RHS
Downy mildew:
- Symptoms:*
- Discoloured areas on upper leaf surfaces & fuzzy grey fungal growth on lower leaf surfaces
- Control measures:*
- Remove infected leaves and dispose of
- Improve air circulation
- Control weeds
