Potatoes - Common Pests and Problems
A wealth of information about the basic techniques for growing potatoes.
Preparing the site
Choose an open position in full sun on fertile, well drained soil. Avoid soil where potatoes have grown for two years in succession as this will increase the risk of disease. A slightly acidic soil is preferable but not essential. When growing potatoes on more alkaline soils, apply sulphur to the top of the potato ridge after planting. This maximizes the yield and deters skin blemishes like Common Scab that are particularly troublesome in alkaline conditions.
Prepare the planting site in November/ December to allow the soil to settle. Remove all weeds and large stones, dig the site thoroughly, incorporating plenty of well rotted organic matter and high potash fertiliser.
Early and second early seeds, benefit from 'chitting' prior to being planted. This process encourages strong shoots to sprout over several weeks which promotes faster growth and heavier crops once they are in the ground. From late January/ February, ‘chit’ your seed potatoes by setting them out in seed trays, shallow boxes or empty egg cartons in a cool, bright, frost free position (10C/ 50F) to allow them to sprout.
You will notice that the immature 'chits' are all at one end (called the rose end). Place the rose end upwards. Sturdy 'chits' will form and should attain up to 25mm (1") in length.
Cutting Seed Potatoes
Seed potatoes will often vary in size. Don’t be concerned, they will all grow equally well. In fact, during the 2nd World War it was common practice to cut larger seed potatoes in half or even smaller divisions to make the seed potatoes go further. The cuts should be left to dry out for 3 or 4 days before planting in the usual way. Provided that each piece has an eye or two for the new growth to develop, these tuber divisions will still crop well.
Nowadays, seeds are cheap and widely available so there is generally no need to do this unless you receive particularly large seed potatoes with lots of eyes.
How to Plant Potatoes
Planting times are largely dependent on weather, soil conditions and regional variations, but the table below is a general guide to when to plant potatoes.
Dig a trench to a depth of about 10cm (4") and place the seed potatoes into the trench with the rose end facing upwards. Fill the trench with soil to cover the potatoes. An application of potato fertiliser can be scattered along the top of the trench if required.
|Crop Type||Planting Time||Planting distance in row||Distance between rows||Approximate harvest time|
|First early potatoes||From end of February||30cm (12") apart||60cm (24") apart||10 weeks from planting|
|Second early potatoes||From mid March||37cm (15") apart||75cm (30") apart||13 weeks from planting|
|Early maincrop potatoes||From late March||45cm (18") apart||75cm (30") apart||15 weeks from planting|
|Maincrop potatoes||From late March||45cm (18") apart||75cm (30") apart||20 weeks from planting|
|Second cropping potatoes||Early August||30cm (12") apart||60cm (24") apart||11 weeks from planting|
It is important to ‘earth up’ potato crops as the shoots emerge above ground, to protect them from frosts which blacken the shoots and delay production. Simply draw some soil over the top of the shoots to cover them again. First early and second early crops particularly require plenty of water during prolonged dry weather especially when tubers are starting to form. When the stems reach a height of 23cm (9") above ground they should be earthed up again to prevent tubers near to the soil surface from turning green.
Lifting times vary depending on the growing season, weather conditions and size of tuber you want. The table above provides a rough guide for each crop type. Harvest first earlies as 'new potatoes' when the plants begin to flower. Tubers will generally become larger the longer their growing period. Main crop varieties are usually left for at least two weeks after the leaves and haulms (stems) have withered, to allow the skins to set. Cut down the stems with secateurs to just above soil level as the leaves wither and yellow, or if they show signs of blight.
After harvesting, leave the tubers on the soil surface for a few hours to dry before bagging.