Vegetable Crops PLSC 451/551 Lesson 22, Salad Crops Instructor: Stephen L. Love Aberdeen R & E Center 1693 S 2700 W Aberdeen, ID 83210 Phone: 397-4181 Fax: 397-4311 Email: slove@uidaho.edu Salad Crops General Information Wide range of species, from many families Grown for large or succulent edible leaves Usually eaten uncooked, but occasionally as potherbs Production systems vary widely Dandelion Species: Taraxacum officinale (aster family) Origin: Eurasia More commonly known as a weedy pest Often gathered rather than cultivated (subsistence) Some varieties exist-europe, Asia (market gardens) Flowers and roots also edible 1
Paracress Species: Acmella oleracea (aster family) Origin: Brazil Mostly used in Brazil and Malaysia Seldom cultivated (subsistence gathering) Adds sharp flavor to salads, moderates capsaicin Flower buds used to treat toothaches Rocket Salad Species: Eruca vesicaria (mustard family) Origin: Southern Europe/Western Asia Partially domesticated, often cultivated Leaves make a sharp-tasting addition to salads Flowers are also edible Seeds produce a hot-flavored oil Coriander Species: Coriandrum sativum (carrot family) Origin: Western Asia Small-scale production worldwide Production: from modern-intense (cilantro seed) to market-garden/subsistence (salad coriander) Common in Asian and Mexican cuisine Annual growth but harvested multiple times 2
Parsley Species: Petroselinum crispum (carrot family) Origin: Mediterranean region Traditionally used for medicinal purposes Leaves used as garnish/flavoring, soups, stews Biennial or perennial harvested multiple times Small-scale modern production for processing, market-garden production for fresh use Amaranth Species: Amaranthus tricolor Native of Central and South America Greatest diversity in India Mostly subsistence production Leaves edible in uncooked salad dishes One species important for seed grain (quinoa) Basella Basella Species: Basella rubra Native to tropical Asia Native to tropical Asia Perennial vine to 12 feet tall Leaves edible in salads (tastes like spinach) Pigment in leaves and fruit used as edible dye 3
Purslane Species: Portulaca oleracea Native of India or Iran Common weed throughout the world Often gleaned from uncultivated sites Some domesticated forms cultivated (subsistence) Succulent leaves edible, high in iron Borage Species: Borago officinalis Origin: Mediterranean Foliage, tender stems and flowers edible Salad use in Germany, flavors pickles in Poland Most common use is for seed oil Subsistence or small market-garden production Good companion plant to deter insect pests Other Minor Salad Crops Upland Cress (Barbara verna) western Europe Garden Cress (Lepidium sativum) - Europe Salad Chervil (Anthriscus cerefolium) Europe, US Asiatic pennywort (Centella asiatica) - Indonesia Garden sorrel (Rumex acetosa) Europe, Africa New Zealand spinach (Tetragonia tetragonioides) Water cress (Nasturtium officinale) - worldwide Corn salad (Valerianella locusta) - Mediterranean 4
Endive Description Species: Cichorium endiva (sunflower family) Native to the Mediterranean region Important salad crop in Europe, increasingly in U.S. Edible portion is a loose head of leaves Many types with broad, curled or fringed leaves Can be bitter and harsh, differential sensitivity in humans Chicory Description Also known as French endive, witloof chicory Species: Cichorium intybus (endive Genus) Native to the Mediterranean region Important salad crop in Europe, some in U.S. Edible portion is apical bud, roots eaten in some types Forcing commonly practiced (second-year growth of biennial type forced the first year) Spinach Origin and domestication Species: Spinacia oleracea (beet family) p p ( y) Native of southwest Asia (Iran) Cultivated for about 2000 years Grown in Europe around 1000 AD Brought to North America by European settlers 5
Spinach Use and production Traditionally a potherb, now important salad crop Considered of high value nutritionally Important in the U.S and some parts of Europe Major producing states: California, Colorado, Texas, New Jersey, Maryland Total U.S. production 15,000 acres Spinach Harvest and Storage Fresh spinach hand harvested whole plant pulled, trimmed harvest done late day, less turgidity Processed spinach machine harvested cut at the top of the petiole, bulk handled Cooled with crushed ice, generally not stored Celery Origin and domestication Species: Apium graveolens (carrot family) Biennial grown as an annual Native to Mediterranean region, North to Sweden Cultivated before 850 BC First used for medicinal purposes Domestication increased size, decreased bitterness 6
Celery Use and production Edible portion is the leave petiole, roots are used and known as celeriac Consumed raw or cooked in soups and stews Important vegetable in North America and Europe California, Texas, Michigan, Ohio major producers U.S. total production 27,000 acres Celery Varieties Green types Utah, Pascal, Ford dhook Self-blanching types Golden Self Blanching, Sanford Superb Celeriac Prague, Delicacy Smallage (minimal use, few varieties) Celery Management techniques Environmentally demanding crop Mean temperatures 60-70 degrees Sensitive to freezing Bolts following cool temperatures (50 degrees) Shallow rooted, requires irrigation Heavy feeder, high use of N 7
Celery Management techniques Slow seed germination (15 days minimum) Exhibits thermodormancy above 75 degrees Far-red light helps eliminate thermodormancy Seed often pelleted Transplanting often practiced to overcome germination problems Taxonomy Family: Asteraceae (Compositae) Family: Asteraceae (Compositae) family with 20,000 species, few cultivated Genus and species: Lactuca sativa Related species: sunflower, dandelion, globe artichoke, endive 8
Taxonomy Subspecies capitata head lettuce crispa leaf lettuce longifolia Cos or Romaine lettuce aparagina stem or asparagus lettuce Origin and Domestication Native to the Mediterranean region Wild types are prickly and contain latex Grown in Egypt as early as 4500 BC Early use medicinal and for seed oil Domestication resulted in slow bolting, lack of spines, non-shattering seed, large leaves Head lettuce first described in 1543 Latex production in wild types 9
Importance Most popular pp salad crop In U.S., value among vegetables second to potatoes Considered a pleasure food High in vitamin A, calcium, iron Low in calories and other nutrients World Production World acreage 700,000000 acres Grown throughout the temperate regions Amenable to all production systems Common subject for organic production Consumer use Used almost entirely as a raw vegetable alone Used almost entirely as a raw vegetable alone or in salads Heavily used by the restaurant industry Produced and marketed throughout the year 10
Climate and soils Require a cool climate optimum 70 degree day, 50 degree night Seedlings resistant to moderate frost Maturation rate temperature dependent Varieties are mostly daylength neutral, but: Long days encourage bolting under high temps Stand Establishment Mostly direct-seeded, thinned Planted shallow (light requirement) ¼indeep Soil must be well-worked, smooth Compacted soil severely limits emergence Phosphoric or sulfuric acid anticrustants Irrigated regularly during germination Mulches commonly used Thinned 10-12 in apart on raised, double beds (36 in) Physiological problems Tipburn necrosis of inner leaf margins local calcium deficiency, more N helps Russet spotting reddish spots on midrib interaction of ethylene and temperature avoid ethylene (lower than.5 ppm) maintain temperatures at 32-35 degrees 11
Physiological problems Tipburn necrosis of inner leaf margins local calcium deficiency, more N helps Russet spotting reddish spots on midrib interaction of ethylene and temperature avoid ethylene (lower than.5 ppm) maintain temperatures at 32-35 degrees Production - Harvest Harvest indices Head of adequate size Head firm Leaves green No bolting Production - Harvest Multiple harvests (small production) Hand harvested (machine assist) Common to harvest, trim, pack in the field Limits handling Reduces injury Eliminates waste disposal 12
Handling and Storage Field packed in marketable cartons Vacuum cooled to <50 degrees within 1 hour Not hydrocooled (pathogens) Usually not stored Can be at 33-34 degrees, 90-95% RH, 1-2 weeks Not stored or shipped with ethylene producers 13