Potatoes

Question 1

What are the best temperatures to grow potatoes?

Answer 1

Between 16C and 18C.

They require 90 to 140 frost-free days to reach maturity.

Question 2

What are the advantages and disadvantages of early and second early varieties of potatoes compared to maincrop?

Answer 2

Early and second early potatoes:

• Generally do not suffer potato blight
• Crop when potatoes in shops are still expensive
• Require less space than maincrop and crop more quickly

Disadvantage:

• Smaller yields than maincrop.

Question 3

Explain site selection and soil for potatoes.

Answer 3

• Not terribly fussy
• Prefer an open site (especially earlies)
• Must be protected from frosts
• Slightly acid soil (pH 5 - 6)
• Rotate crop site.

Question 4

Explain soil preparation for potatoes.

Answer 4

• Dig in plenty of organic matter the autumn before planting
• Secondary soil cultivation two weeks before planting, including applying 100g/m2 of Growmore.

Question 5

Explain sowing of first and second early crop potatoes.

Answer 5

• First earlies sow March, second earlies sow early April
• 10cm deep in trenches
• 35cm between tubers
• 45cm between rows
• Chitting required
• Sow end of March (earth up once, when 15cm high).

Question 6

Explain sowing of maincrop potatoes.

Answer 6

• 15cm deep in trenches
• 40cm between tubers
• 70cm between rows
• No chitting required
• Sow end of April (and earth up twice).

Question 7

When do you harvest the various types of potato crops?

Answer 7

• First earlies: end of June
• Second earlies: July
• Maincrop: Mid September (in sunny, dry weather).

Question 8

What is important about selecting potatoes to sow?

Answer 8

Select certified, disease-free seed potatoes.

Question 9

What is chitting?

Answer 9

• Chitting is a process that prepares early and second early potatoes for sowing.
• Place seed potatoes in a seed tray, eyes-upwards, and place them in a dry, light, frost-free place.
• This encourages shoots to grow, giving them a headstart when planted
• Plant out when shotos 2cm long.

Question 10

Explain “earthing up”.

Answer 10

Earthing up is pulling the soil up around the potato plants

Do this when the plants reach 20cm in height. Always leave 10cm of leaves above the ground

Continue to earth up as the plant grows

Earthing up encourages tuber production and prevents tubers near the surface from turning green.

Question 11

Explain the irrigation of potatoes.

Answer 11

• Regular watering improves both yield and health
• Apply 20L/m2 every two weeks during dry spells
• Avoid overhead irrigation as this washes potato blight spores down into the soil.

Question 12

Name a pest and a disease of potatoes, including symptoms and control methods.

Answer 12

Potato Cyst Eelworm

• A nematode that turns the plant yellow, and it starts dying at the base. Tubers remain small and brown. Cysts present on roots.
• Use crop rotation; Choose resistant cultivars; Good hygiene; Remove and burn infected material.

Potato Blight

• Fungal disease leaves brown patches on leaves, with white fungal fringe underneath. Foliage eventually browns and dies off completely. Brown sunken lesions on flesh of tubers. Tubers may rot in ground
• Avoid overhead watering; earth up early; Choose resistant cultivars; avoid growing near tomatoes; use preventative fungicide.

Question 13

Name three first early crop potato cultivars.

Answer 13

• ‘Accord’
• ‘Rocket’
• ‘Swift’.

Question 14

Name three second early potato cultivars.

Answer 14

• ‘Lady Balfour’
• ‘British Queen’
• ‘Maris Peer’.

Question 15

Name three maincrop potato varieties.

Answer 15

• ‘Constance’
• ‘Cara’
• ‘Desiree’.