Agriculture Reference
In-Depth Information
flower until the spring. If they begin to look leggy early in the year, move them
to a sunny windowsill or provide extra light until the weather picks up.
Once established, sweet potatoes need little feeding and have only moderate
demands for water. They do not tolerate being waterlogged for long, which is
why we recommend planting them in mounds or ridges. If you decide to feed
them, use a balanced organic fertiliser or one marketed for tomatoes, as nitrog-
enous fertilisers cause them to produce lots of luxuriant leafy growth rather than
substantial tubers.
Being a member of the bindweed family, sweet potato sends out sprawling vines
which, if left unchecked, may limit the light available to nearby plants. They also
have an irritating habit of rooting from each leaf node, and this should be dis-
couraged by lifting the vines periodically - otherwise you get lots of tiny tubers
and fewer big ones. The vines can safely be pruned, but heavy pruning will
reduce the yield of tubers; the variety 'O'Henry' tends to be easier to control as it
has a bushier habit, but, as an alternative, consider providing a growing string
as described in Chapter 6 (page 51). Periodically scoop the vines up into a bunch
and run a loop of twine around them, then secure to one of the fastening loops
on the growing string. Unless you can give the plants all the room they want at
one end of your tunnel, this will need to be done several times.
Sweet potato shoots, young leaves and vine tips are also edible and can be served
raw in salads, stir-fried, or sautéed Taiwanese-style with fried garlic and a little
soy sauce. Be careful not to take too many shoots, as overenthusiastic harvesting
of greens can reduce the tuber harvest.
Harvesting and storage
Once the leaves have begun to yellow, but before the first frosts, carefully lift the
plants with a fork and shake them as you would with potatoes. There will be a
few sweet potatoes at the base, and although these will be smaller than the
imported ones sold at market, once cured they will be seriously tasty.
Sweet potatoes have a starchy flavour when freshly dug and should be cured for
a couple of weeks in a warm, dark, humid place before using. This curing process
also allows the skins to set and any wounds to seal, making them store better.
Once cured, move the roots to a cool (but not cold, 10-16°C) place with good air
circulation and preferably high humidity, where they will store well for several
months, provided that they do not get cold. Never store sweet potatoes in the
fridge, and resist the urge to wash them until you are ready to eat them.
Sweet potatoes can be also dried after blanching in boiling water for three min-
utes, or can be cooked and frozen whole, sliced or mashed. To stop the lovely
orange colour from deteriorating, dip the cooked pieces in a weak solution (one
