Cress

Description

Garden cress, Lepidium sativum, is an herbaceous annual in the family Brassicaceae grown for its edible shoots and leaves which are grown as a salad green. Garden cress is a fast growing plant with many branches and narrow, oval leaves. The plant produces small pink to white flower which are 2 mm (1/12 in) in diameter and form a highly clustered inflorescence. It can reach a height of 60 cm (23.6 in) and although classed as an annual it can behave as a perennial as it may drop seeds before harvest that will grow the next year. Garden cress may also be referred to as pepper cress or Persian broadleaf cress and it originates from Persia (Iran).


Uses

The shoots and leaves of garden cress are used as a salad green or seasoning as they has a peppery taste. The seeds may also be ground and used as a seasoning.


Propagation


Basic requirements
Garden cress is a cool season annual and can grow in almost any type of soil as long as it is moist and rich in nutrients. Cress will grow best in a well-draining loam soil with a pH between 6.0 and 6.7. The plants should be grown in full sun or partial shade in areas where temperatures get very high. Cress plants will tolerate some frost.

Planting
Garden cress is propagated by seed and can be sown as soon as the soil is workable in the Spring. The seeds are sown either by broadcasting or arranging the plants in rows. Rows should be spaced 7-10 cm (3-4 in) apart. The seeds should be covered with a light layer of soil and kept moist. Cress will germinate in 2 to 7 days and the plants do not usually require thinning. The plants will grow best if the soil is kept moist.

General care and maintenance
Cress is very easy to grow and care for. The plants will grow best if kept moist so the plants should be watered regularly. Keep beds weed free to prevent competition with the developing plants. Due to its short growing period, cress has a low fertilizer requirement. Container grown plants can be fertilized with a liquid fertilizer if required.

Harvesting
Cress can be harvested 2 to 3 weeks after the seedlings emerge once the leaves have reached 3 cm (2 in) in length. Harvest older plants first by snipping with a pair of scissors and leave the younger ones to develop fully.


References

Anderson, C. R. (1995). Garden Cress. University of Arkansas Division of Agriculture Home Gardening Series. Available at: http://www.uaex.edu/publications/pdf/.... [Accessed 19 November 14]. Free to access.

Allan, B. & Drost, D. (2010). Garden Cress in the Garden. Utah State University Cooperative Extension. Available at: https://extension.usu.edu/files/publi.... [Accessed 19 November 14]. Free to access.




Common Pests and Diseases

Black rot
Xanthomonas campestris

Symptoms
V-shaped yellow or orange discoloration spreading from leaf edge to the center; black leaf veins; leaves falling off
Cause
Bacteria
Comments
Pathogen is spread via infected seed or by splashing water and insect movement; disease emergence favored by warm and humid conditions
Management
Primary method of controlling black rot is through the use of good sanitation practices; rotate crops to non-cruciferous crops every 2 years; plant resistant varieties; control cruciferous weed species which may act as a reservoir for bacteria; plant pathogen-free seed

Damping-off
Pythium spp.
Rhizoctonia solani

Symptoms
Death of seedlings after germination; brown or black rot girdling stem; seedling may remain upright but stem is constricted and twisted
Cause
Fungi
Comments
Disease emergence in seedlings favored by cool temperatures
Management
Plant pathogen-free seed or transplants that have been produced in sterilized soil; apply fungicide to seed to kill off any fungi; shallow plant seeds or delay planting until soil warms

Alternaria leaf spot (Brown spot)
Alternaria brassicae

Symptoms
Brown lesions on leaves; brown or yellow concentric rings developing from lesions
Cause
Fungus
Comments
Favors warm, wet weather

Anthracnose
Colletotrichum higginsianum

Symptoms
Small circular or irregularly shaped dry spots which are gray to straw in color on leaves; a high number of spots may cause the leaf to die; lesions may coalesce to form large necrotic patches causing leaves to turn yellow and wilt; lesions may split or crack in dry centers
Cause
Fungus
Comments
Fungus overwinters on leaf debris and on related weeds; disease emergence is favored by moist, warm conditions
Management
Control of disease depends on sanitary practices; treat seeds with hot water prior to planting; rotate crops; plant in an area with good soil drainage; remove all cruciferous weeds which may act as a reservoir for the fungus

Blackleg
Phoma lingam

Symptoms
Damping-off of seedlings; round or irregularly shaped gray necrotic lesions on leaves with dark margins; lesions may be covered in pink masses in favorable weather conditions
Cause
Fungus
Comments
Disease favors warm, wet weather; water splash contaminated tools can spread the disease
Management
Use disease free seed or treat with hot water to remove fungus prior to planting; remove and destroy crop debris after harvest or plow deeply into soil

Clubroot
Plasmodiophora brassicae

Symptoms
Slow growing, stunted plants; yellowish leaves which wilt during day and rejuvenate in part at night; swollen, distorted roots; extensive gall formation
Cause
Fungus
Comments
Can be difficult to distinguish from nematode damage; fungus can survive in soil for periods in excess of 10 years; can be spread by movement of contaminated soil and irrigation water to uninfected areas
Management
Once the pathogen is present in the soil it can survive for many years, elimination of the pathogen is economically unfeasible; rotating crops generally does not provide effective control; plant only certified seed and avoid field grown transplants unless produced in a fumigated bed; applying lime to the soil can reduce fungus sporulation

Downy mildew
Peronospora parasitica

Symptoms
White, fluffy mold on the underside of leaves; yellowing of the top side of the leaf; black lesions on leaves
Cause
Fungus
Comments
Disease favors cool, humid weather
Management
Remove all crop debris after harvest; rotate with non-brassicas; application of appropriate fungicides may be required if symptoms of disease are present

Flea beetles
Phyllotreta spp.

Symptoms
Small holes or pits in leaves that give the foliage a characteristic “shothole” appearance; young plants and seedlings are particularly susceptible; plant growth may be reduced; if damage is severe the plant may be killed; the pest responsible for the damage is a small (1.5–3.0 mm) dark colored beetle which jumps when disturbed; the beetles are often shiny in appearance
Cause
Insect
Comments
Younger plants are more susceptible to flea beetle damage than older ones; older plants can tolerate infestation; flea beetles may overwinter on nearby weed species, in plant debris or in the soil; insects may go through a second or third generation in one year
Management
In areas where flea beetles are a problem, floating row covers may have to be used prior to the emergence of the beetles to provide a physical barrier to protect young plants; plant seeds early to allow establishment before the beetles become a problem - mature plants are less susceptible to damage; trap crops may provide a measure of control - cruciferous plants are best; application of a thick layer of mulch may help prevent beetles reaching surface; application on diamotecoeus earth or oils such as neem oil are effective control methods for organic growers; application of insecticides containing carbaryl, spinosad, bifenthrin and permethrin can provide adequate control of beetles for up to a week but will need reapplied