How To Grow Potatoes & Sweet Potatoes

Potatoes

Potatoes will grow in a wide range of soils, though they do best in moisture-retentive ground. Prepare the ground in autumn by digging in plenty of manure or compost.

When you receive your tubers, chit them by placing each potato 'eye' face up' in egg boxes or shallow trays. Stand them in a warm, light location.

Once small green shoots (or chits) appear (this can take several weeks) move the trays to a cooler location for a few weeks before planting out. First Earlies are best planted out mid March - April. Later plantings will be fine but the yield may be smaller.

To plant your tubers, dig trenches approximately 5" (12 cm) deep. For First Early potatoes, space the trenches 2 feet (60 cm) apart. For Second Early/Maincrop Potatoes, space the trenches 2'6" (75 cm) apart. Press tubers into the base of the trench 12" (30 cm) apart with chits facing up and then cover with soil. Water in.

Weed regularly, and keep the crop well watered in dry spells. When the haulm (top growth of the plants) reaches 9" (23 cm) earth up around the plants leaving just the top 4" (10 cm) showing. Repeat again later if required.

Pentland Javelin should be ready to harvest approximately 10 weeks after planting. Forest Gold, Home Guard and International Kidney should be ready for harvest approximately 10-15 weeks after planting. Nicola and Pink Fir Apple should be ready to harvest approximately 16-20 weeks after planting.

Sweet Potatoes

Sweet Potatoes like a sunny position and need a moisture-retentive, free-draining soil.

Ideally they need to be grown under protection, in a greenhouse, polytunnel or something similar for best results. Grow in large tubs, growbags or in the greenhouse border. Plant 12-18" (30-45 cm) apart. The foliage can be trained up strings, canes or a trellis. Sweet Potatoes crop best at temperatures between 70-80ºF (21-26ºC).

Keep well watered and feed fortnightly with a high-potassium liquid feed.

Sweet Potatoes can also be grown outdoors, in a sunny position, in which case the soil should be warmed up, using black polythene, for several weeks before you intend to set out the plants. Plant in late March-April. Harden off plants before putting them out. Plant through slits cut in the polythene, and cover with horticultural fleece to keep up the temperature.

Tubers take 90-120 days to mature, and should be lifted once the leaves turn yellow and start to die back.