Leafy Vegetable Crops

Quick Facts...

• Leafy vegetables contain more vitamins and minerals and fewer calories than any other vegetables.
• They are ideal for summer lunches when heat dulls the appetite and the desire to cook.
• Leafy vegetables do well under cool conditions and can be eaten at any stage of maturity, which makes them ideal for regions with a short growing season.
• With proper selection, culture and storage, leafy vegetables can be available most of the year.

Leafy vegetables are easily grown, rich in vitamins and minerals, contain relatively few calories, and are enjoyed most when harvested fresh. They are ideal for the cool temperatures and short seasons of high altitudes because they can be eaten at any stage of maturity.

When properly selected, planted, grown and stored, leafy vegetables can be available year round. This is achieved with an April planting of spinach, lettuce and cabbage, a May planting of Swiss chard, and an August planting of lettuce and spinach. Harvest cabbage in October and store in a pit for winter use (see fact sheet 7.601, Storage of Home-Grown Vegetables). In November, mulch spinach; remove the mulch in March. Harvest the leaves after growth resumes.

Black plastic mulch is helpful to warm the soil in the spring, conserve moisture and control weeds. A winter mulch of straw and soil over spinach and parsley helps bring them through the winter for production of early spring greens.

Soil Fertility and Plant Growing

Leafy vegetables, in general, do not have extensive root systems. Therefore, Gardeners must concern themselves with the conditions in the top 6 inches of soil. Supply the soil well with organic matter, nutrients and water. Leafy vegetables, like lawns, require high nitrogen levels. A general recommendation is to apply 1 pound of nitrogen and 1 pound of phosphate before planting and another pound of nitrogen on July 1, per 1,000 square feet.

Seed size among leaf Crops varies widely. A good rule is to plant seed to a depth of eight times its thickness and keep the soil in the seed zone moist until the seedlings emerge. Plant two or three seeds for each plant desired. These extra seeds are not necessarily wasted, because when the seedlings begin to crowd they may be thinned and used for salad. The row spacing varies from 1 to 3 feet, and the spacing in the row varies from 2 to 24 inches, depending on plant size at maturity.

Harvesting

Commercially, whole plants are harvested mechanically. However, it usually is best for the home Gardener to harvest individual leaves. In this way, the plant is left in the Garden to regenerate more leaves for successive harvests. Consider regeneration when deciding between head and loose-leaf varieties. When a head variety matures, the whole head is harvested.

Pests

Expect to find weed, insect and disease pests whenever a Garden is planted. These may be controlled manually: the weeds with a hoe, the diseases by removing the affected leaf or plant, and the insects by picking or washing them off the plant. When manual means are not practical, use a general Garden insecticide (malathion) at 2 teaspoons per gallon of water. Remember, the leaves will be eaten, so use chemicals cautiously. Wait the required number of days before harvesting and wash leaves thoroughly before eating. Store chemicals properly and always use them according to label directions.

Varieties

Brussels sprouts. (Rider.) May be direct-seeded or transplanted. Sprouts will form in the axils of the leaves, beginning with the lower leaves. Harvest sprouts at 1 inch in diameter to keep plants productive. Harvest extends from August to November.

Cabbage. (Green: Grand Prize, Polar Green, Grenadier, Quick Step. Red: Red Rookie. Savoyed: Savoy Chieftain. Chinese: Yoko.) Cabbage is used in salads or coleslaw, boiled, baked, processed into sauerkraut, or pit stored. Schedule storage or sauerkraut cabbage to mature in the fall.

Celery. (Dwarf Golden Self-Blanching, Utah 52-70 R Imp.) Transplants should be 10 weeks old when planted during June. Earlier transplanting may encounter cold weather that can cause bolting. Celery is one of the more difficult Crops for a home Gardener.

Chard, Swiss chard. (Light green: Lucullus. Dark green: Fordhook Giant. Red veined: Rhubarb.) Desirable because of its heat tolerance. Provides greens and salads from July to October.

Chicory. (For greens: Radichetta, Gold Lace. For overwintered greens or forcing: Witloof.) To force, harvest mature roots and replant in sand to produce blanched heads in darkness.

Collards. (Flash, Vates.) Like mustard and kale, it is a member of the cabbage family. It will stand more heat and cold than other members of this family and therefore is a valued long-season green. Plants remain productive if the growing center remains untouched while harvesting only the outer leaves.

Dandelions. Cultivated dandelions have been developed to produce on a par with other greens. Instead of planting dandelions, dig those in the lawn, which improves the appearance of the lawn and provides greens. The lawn, of course, should be chemical-free.

Endive, escarole. (Plain leaf: Bossa, Race Salanca. Ruffled leaf: Salad King, Tasos.) Leaves are used for garnish, salads and greens. The blanched white hearts are a delicacy.

Garden cress. A cool-season crop more popular in Europe than the United States. Leaves are ready to harvest six to eight weeks from time of sowing.

Kale. (Light green ruffled: Bona. Dark green ruffled: Winterbor. Dark green, purple veins: Red Russian.) Kale holds up well in cold weather and is a dependable green until the ground freezes.

Lettuce. (Loose leaf dark ruffled: Black-seeded Simpson. Loose leaf light ruffled: Simpson Elite, Slobolt. Loose leaf red: Rouge Salad Bowl, Sierra - tinged. Oakleaf dark: Royal. Oakleaf red: Brunia, Dapple. Butterhead dark, flat: Sudi, Optima. Butterhead light: Cindy - flat, Nevada - ruffled. Romaine dark: Romulus, Verte Mar. Iceberg not recommended.) Sow lettuce in April and again in late July. Keep soil surface moist until seedlings emerge. Leaf lettuce is most practical for a home Garden because leaves can be harvested as needed, leaving the plant to regenerate more leaves.

Mustard. (Dark ruffled: Green Wave.) Plant for early summer or fall crop. Goes to seed in hot weather.

New Zealand spinach. Not really a spinach, but tolerates warm weather and continues to produce all summer. Harvest by breaking off 2 inches of the growing tips and use like spinach.

Pak choi. (Mei Oing Choi, Joi Choi.) Pak choi is recognized by its rounded green leaves with white petioles. It is a popular green in oriental cooking.

Parsley. (Dark, cut, curled leaves: Garland, Krausa.) Parsley is a cool-season crop that does best in spring and fall. Use as a garnish and as a flavoring. Overwinter for early spring production before it bolts.

Radicchio. (Dark red/green, ovate leaf: Chioggia Red, Prima Rossa. Green, upright, strap leaves: Verona. Small red head: Medusa.) Use in salads.

Spinach. (Carambole, Tyee, Marathon, Long Standing Bloomsdale, Indian Summer, Medania.) Spinach bolts in warm weather, although these varieties are slower to bolt than others. Plant the spring crop in April and the fall crop in August.

Watercress. Not related to Garden cress. Water cress beds usually are established around limestone springs in clean, running water. Few Gardeners can produce it because it requires such a unique aquatic habitat.

¹ J.E. Ells, Colorado State University Extension vegetable crop specialist and associate professor, horticulture (retired); revised by D.E. Whiting, Extension ornamental horticulture specialist; horticulture and landscape architecture. 10/99. Reviewed 11/03.

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