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Sweet Potatoes

Ipomoea batatas

INTRODUCTION

Sweet Potatoes, often confused with Yams, are native to central and southern America and have been in existence for over 5000 years. A tender perennial, they should never be exposed to frost.

Sweet Potatoes are not related to standard Potatoes but are related to common bindweed. Colours can vary from purple to gold or white, as well as the more usual orange. It is a highly nutritious vegetable and a staple diet in Polynesia. The Sweet Potato is high in carbohydrates, rich in beta-carotene and vitamins A, B, and C. They are also low in fat and high in dietary fibre.

Soil Preparation

Sweet Potatoes require rich fertile sandy soils that can retain water without being waterlogged.

This crop thrives in subtropical climates and suits polytunnel growing well. The growing area must be maintained at 24oc and above with relatively high humidity.

If covered growing is not an option, ensure the site is south facing and in full sun.

Soil pH should be slightly lower than many crops, ranging if possible 5.5-6.5

Sowing & Planting

Unlike normal Potatoes, Sweet Potatoes are not grown from tubers or even seeds, but from cuttings or 'slips'.

Slips or cuttings can be taken from your own homegrown stock plants or purchased from a specialist supplier.

If taking your own cuttings, plant Sweet Potato tubers in a mixture of moist compost mixed with sand or perlite and wait for shoots to appear. Take cuttings at about 5cm in length and root in a propagator.

As an alternative, you can find a list of seed suppliers in the GrowMad Seed Directory, many of whom will carry a range of ready-to-plant Sweet Potato slips.

Growing & General Cultivation

Plant Sweet Potato slips into ridges (slightly raised soil level) as soon as temperatures are high enough. Ensure all risk of frost has passed.

Plant the slips 30cm (12 inches) apart, with 75cm (30 inches) between each row.

As an alternative, plant into containers or Potato grow bags.

Keep well watered, especially during dry weather, ensuring crops never dry out.

Maintain temperatures above 24oc. Sweet Potatoes perform at their best in hot humid conditions with 14+ hours of daylight.

Sweet Potatoes have a trailing habit. If they become unruly, reduce the length of shoots.

Keep plants weed-free.

Pests & Diseases

Aphids can feed on growing foliage and be unsightly as well as responsible for spreading virus. Biological control is available. See GrowMad Product Directory.

Whitefly can infest crops of Sweet Potato, particularly on indoor grown plants. The Whitefly feed on the plant's sap and in turn secrete a sticky honeydew which will lead to black sooty moulds being present. Biological control is available. See directory for details.

Red Spider Mite shows up as yellow mottling on the foliage. On the underside of leaves, webbing will become obvious in severe cases, with mites clearly visible. The pest is normally more of an issue on indoor crops, particularly during hot, dry weather. Biological control is available. See directory for details.