Growing Cresses and mustard
This group of cruciferous salad plants containsand land —which are grown into the mature state before harvesting—and and cress, which are used as . The methods of growing the different plants are so dissimilar that they will be considered separately.
This British native plant grows wild in ditches and streams but is also cultivated on a commercial scale. It has a distinctive mustard-like flavour and is eaten raw as a salad vegetable or used for decoration with other dishes. Watercress is a more or less hardy perennial of which two forms are grown. The green-leaved type is easier to establish but is frost susceptible while the bronze or winter watercress is hardier. Production
The best environment for this plant is in an uncontaminated stream of gently running water. It is important to ensure that sewage or detergent do not pollute the watercourse. Watercress is easily propagated from young shoots—in fact purchased material will frequently develop roots within a few days if stood in a jar of water. Rooted10cm (4in) long should be planted into the banks and bottom of the stream at 15-cm (6-in) intervals. Growth will be rapid and cutting should begin after about 6 months of active growth. Watercress can be grown in the absence of running water provided a constantly moist environment is maintained. Choose a shaded site and prepare a trench
which is 15cm (6in) deep and 40cm (16in) wide and thoroughly soak it before planting rooted cuttings as before. Keep the trench regularly watered to sustain the plants. Never allow the plants to flower as this reduces vegetative growth. Small-scale production is possible in sub-irrigated pots and sunken sinks while winter supplies can be maintained by coveringor water beds with cloches, polythene tunnels or frames.
American or Land cress
An uncommon biennial salad plant which we grow as an annual for the watercress-like leaves. When plants are protected by cloches, frames or polythene tunnels they produce useful supplies of winter cress. Production
From mid-March onwards sow seed thinly in drills which are 1cm (1/2in) deep and 30cm (12in) apart. After emergence thin the plants to 15cm (6in) apart. Sowings made in spring and summer will be ready in 8 to 10 weeks. Protect late summer sowings with cloches or polythene during the winter.
Mustard and cress
Sinapis alba and Lepidium sativum
This should more accurately be called rape and cress since white mustard (Sinapis alba) is usually replaced by the greener, longer-standing and better flavoured rape (Brassica napus). Curled and plain cress cultivars are available. These annual plants are grown into seedlings which are then cropped at 5cm (2in) long for use in salads and sandwiches. It is possible to have year round production if a minimum temperature of 10°C/50°F can be maintained. There are one or two specialist mustard and cress nurseries which produce all this country’s requirements. Production Mustard and cress is very easy to grow at home on the windowsill. Cover the bottoms of shallow plastic dishes with blotting paper or kitchen towel and give them a thorough watering. Cress takes between 2 and 3 weeks to reach maturity and requires 3 or 4 days longer than mustard/rape.
Sow the containers of cress first and the companion containers a few days later. Weekly sowings are necessary to ensure continuous supplies. Scatter the seed thickly on the damp pads and keep in the dark—in an airing cupboard or under black polythene— until germination takes place. Then keep the containers in full light and well watered until the seedlings are ready for cutting.
Pests and diseases
None of the cresses are particularly prone to pest and disease attack.