Agriculture Reference
In-Depth Information
a worthwhile harvest. But it is reasonably reliable when grown in a polytunnel
- provided that you have room. Sweet and spicy with a creamy texture, this ver-
satile root is traditionally baked, roasted or mashed but can be substituted for
ordinary potato in pretty much any recipe to give an interesting twist to many
winter dishes.
Sweet potatoes are not grown from seed, but are commercially available as 'slips'
(cloned cuttings) or young plants. Both options are relatively expensive, but
resist the urge to grow from tubers bought with your groceries as the varieties
used are unlikely to do well in the British climate, even under cover. Besides,
once you have some plants on the go it is easy to root some stem cuttings every
August, giving them just enough time to establish themselves in pots for the
winter. This gives a strong plant that will need potting up before planting in May,
and if the plants don't survive the winter you can still use one of your stored
tubers to provide a supply of root cuttings in February.
Preparation
Add a top dressing of 5-7.5cm of compost and fork it into the top layer. If your soil
is not naturally free-draining, create a 15cm-high ridge for the plants, or a row of
mounds 45cm apart.
Stem cuttings
In early August, use a sharp, sterile knife (a Stanley or craft knife is ideal) to cut
the tips off strong stems from a part of the plant that receives good light, making
sure that they have at least three leaf nodes. Remove the lower leaf and any flowers
and place the cuttings in a jar of water, then put the jar in a shady place. Within
a few days roots will be developing and the cuttings can be planted into large
pots of a 3:1 mix of seed compost and sharp sand or horticultural grit, leaving
only the top set of leaves exposed. If conditions are very hot, supply some shade
and water regularly until the plants are established.
Root cuttings (slips)
In February, place a sound tuber in a large clear glass-lidded jar (or a large glass
bowl covered with cling film), add water to a depth of 1cm, and close the lid
before placing it in a warm, dark place. After between a fortnight and a couple of
months the tuber will first begin to root and then to send out lots of strong
shoots. As soon as the first of these appears, move the jar to a sunny spot indoors
or a warm windowsill. Once each shoot reaches 10-15cm long, gently rub it off the
tuber and pot up as described for stem cuttings, above. Put the tuber back in the
jar, where it will continue to produce shoots for several months.
Growing
Pot up as necessary, and plant into the soil beds or 50-litre containers once the
soil has warmed up. In the case of stem cuttings, be careful not to let them
