Page 41 - SV 3 2024

Sweet Potato
Ipomea batatas
This is a less unusual vegetable these days as it is more widely available from seed suppliers usually as slips (unrooted cuttings). With the effects of climate change, it is likely it may be easier to grow in the U.K in the future as it prefers a warmer climate than the normal U.K summer. It will produce better crops in polytunnels or cold greenhouses. If grown in a polytunnel they will produce a decent sized crop here in the U.K and if trained upwards do not take up too much space.
The sweet potato’s natural environment is tropical to semi- tropical areas, and it is thought
to originate from Mexico / South America where it was grown by the Incas; it has also been grown in Asia for centuries and was found in New Zealand being grown by the Māori’s when Captain Cook landed.
They can be propagated by softwood cuttings if you have a tuber or plant to provide them, but they are usually purchased as slips in early spring. These need potting up or
put into seed trays and then into a propagator with bottom heat of 24°C. once rooted pot up into 9cm pots and grow on in a warm environment. When established plant out into a polytunnel, greenhouse or warm sheltered sunny position into good fertile (well composted) soil. The plant produces vigorous vines which should be trained up canes, strings
or trellis which gives more light and stops them spreading too far and rooting into the ground. Do not cut the vines back during the growing period as this can cause the tubers to sprout in the soil and reduces storage time.
Keep the plants growing vigorously and feed with a liquid feed weekly, when the vines die back in the autumn lift the large tubers being careful not to damage them which reduces the keeping quality. To store them it is recommended that they are “cured” by putting the tubers in a temperature of 24 to 28°C with high humidity for 10 days and then move to a dark store at 10 to 15°C.
Salsify
Tragopogon parvifolius
It also goes under the other common names of vegetable oyster and oyster plant. Scorzonera hispanica
Commonly called scorzonera, black salsify or Spanish salsify.
The seed for these two vegetables are available from a number of seed suppliers and I have grown them on two occasions but never got around to using them! So, I must try again sometime, third time lucky!
Salsify and scorzonera are often lumped together as they are grown and used in similar ways as well as both being in the family Asteraceae (formerly Compositae). Both are hardy and will survive outside overwinter in the U.K. salsify is a biennial and will flower and die in its second
Salsify ‘Sandwich Island’
As the growing is the same for both vegetables I will cover them together, they both prefer a deep (45 to 60cm)
well drained soil to produce good long roots. The soil should be reasonable stone free and not freshly manured which can cause forking of the roots. Sow the seeds
year after going to seed. Scorzonera is
a perennial so will overwinter and grow each year, they can be harvested any time over the winter period so are useful winter croppers. It has broader leaves than salsify and the roots are black skinned with a white flesh inside, they tend to be larger than salsify. The roots can bleed if cut or broken so lift carefully to
avoid any damage; they
can be washed and cooked
in the skins and then
peeled before eating or
wash in salt water before
cooking. Scorzonera is
more widely grown in
Holland, France, and
Belgium than here in the
U.K.
Salsify is also more
widely grown in Northern
Europe than in the U.K; it has long thin roots and looks like a long thin parsnip. The flavour is said to be similar to both asparagus and oysters and is delicate! They can be left in the ground overwinter, and the young shoots blanched then used in early salads as can also the flowers.
in-situ in March / April
at 1cm deep and rows
30 to 40cm apart; sow thinly or in stations of two seeds every 10 to 15cms. Germination takes 12 to 15 days if the soil temperature is 12 to 15°C, longer if a lower temperature. Once germinated thin out to one seedling per station or 10cm apart, hoe regularly to control weeds and water
in dry periods although in good soil they should obtain water from deep in the soil. Mulching can help conserve moisture and reduce weed germination and saves watering.
The roots can be harvested from mid- October onwards, but they are fully hardy so can be left in the ground until needed
or harvested in April before they start to regrow. Take care when lifting as the roots are long and easily broken. The roots tend to dry quickly once lifted and shrivel (I speak from experience!) so use quickly
or store in old damp compost in boxes or crates, they will store for 2 to 3 months using this method. They will keep in a fridge for up to a week in a damp polythene bag.
If salsify is left in the ground overwinter and the leaves cut off approx. 25mm above the soil and then earthed up to about 15cm the new shoot growth is blanched and can be used in salads. There are a few cultivars of each plant and the two most common are scorzonera ‘Mammoth Sandwich Island’ and salsify ‘Black Giant Russian.’
They are easy to grow and suffer few pests or disease so are worth a try if you like something different.
The roots can bleed if cut or broken so lift carefully to avoid any damage
Salsify
Simply Vegetables 41