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Growing Greens

Welcome to the confusing world of greens.   Lettuce, Swiss chard, kale, collards, spinach, mustard greens, and, more recently, oriental greens and mesclun, belong to the generic category of greens.

The sign of an accomplished gardener,  or, for that matter, a local farmer, is to have lettuce available about the time the slicing tomatoes and cucumbers are ripened, and greens available throughout the growing season. 

One local greens grower seemed surprised to learn that this year.  He has been unable keep up with the demand!   For a Zone 4-5 gardener/farmer, greens and lettuce seeding should have started around mid-late June. 

Spinach (Chenopodiaceae) does not grow satisfactorily during continually wet weather. If your soil is somewhat heavy, plant on low ridges to provide extra drainage. Give enough space between seeds and save yourself -- and your back-- the rigors of thinning.

More cold-resistant lettuce (Compositae) like 'Winter Density' can be seeded before the butterhead types.  Mache, or Corn Salad, (Valerianaceae) also prefers cool temperatures and can be seeded 2 weeks before the frost-free date.  It's a nice addition to salads and can also be grown in containers or under plants that help shade them.

See also Growing Oriental Greens and Cole CropsConsult the monthly archives in Garden Tips for generic information on growing or Garden Links for sources. 

Source: Home Garden Greens, Revised 12/98 , Douglas C. Sanders, Extension Horticultural Specialist, Department of Horticultural Science, North Carolina Cooperative Extension Service

Leafy greens, such as turnips, mustard, collards, kale, and spinach are cool season crops. They should be grown during early spring or fall for maximum yields and quality, but this season can be extended if desired. Kale and spinach can withstand temperature into the upper teens and are often harvested through winter in the east. The other greens may withstand medium frosts.

Soils
Greens may be grown on a variety of soils. Loams will generally produce the greatest yields but for early spring growth and overwintering, sandy loams are best. Soils should be well drained, rich in organic matter and thoroughly tilled. A pH of 6.0 to 6.5 is desirable for all of the greens except spinach, which thrives best in a soil pH 6.5 to 6.8.

Fertilizers
Leafy vegetables require quick, continuous growth for best quality. They especially need nitrogen for good color and tenderness. Follow soil test
results. For the average soils, use 3 lb of 10-10-10 per 100 ft2 before planting. Sidedress with 3 oz of 10-10-10 per 100 ft of row 3 to 5 times after seeding or transplanting.

Culture
Weeds must be controlled by cultivation or with chemicals. Shallow cultivation is a must. Use a rolling cultivator or bunting cultivator. Irrigation is
essential, especially for the fall crop, since leafy vegetables require adequate moisture for continuous growth and high quality.

Insects
Cabbage worms, loopers, and aphids are major insect pests. Once aphids become established, they are difficult to control. A frequent program will be necessary throughout the production season. Insect problems are much worse in fall crops.

Harvesting
Harvest only healthy and well-formed plants, roots, or leaves. Remove all dis-colored or damaged leaves. Wash thoroughly in clean water to remove sand and dirt.

Turnips
Grow Purple Top White Globe variety when roots and tops are desired. Grow Seven Top or Shoegoin for tops only. Plant rows 12 to 18 inches apart. Space plants 1/2 to 1 inch apart for tops, or 2 to 3 inches apart for roots.Harvest turnips when tops are 4 to 8 inches high. Leaves may be cut above or below the crown. Pull roots when 2 inches in diameter.

Mustard
Grow Southern Giant Curled or Tendergreen (Mustard Spinach) varieties. Plant rows 12 to 30 inches apart, and plants 1 to 4 inches apart. The whole plant may be cut off or the individual leaves may be harvested.

Collards and Kale
Grow the Vates, Morris Heading, or Carolina collard or Winterbor or Toscano kale varieties. Spacing depends on how plants will be harvested. If seed is drilled in the row and the young collard plants are to be harvested, similar to turnip greens, the rows may be 12 to 18 inches apart and the plants 2 to 4 inches apart. If 'head collards' are grown, the rows should be 18 to 35 inches apart and plants set or thinned to 12 to 18 inches apart in the row. About 2 lb of seed are required for direct seeding for each acre. For spring collards, do not use young plants that have been in the open field all winter because they will often go to seed very early. Seed may be planted in protected beds in late winter for transplanting in early spring; seeded in the row in late winter and either cut as young greens or thinned; seeded in the row in late spring to mid-summer to be either transplanted, thinned, or left just as they were seeded and cut for young greens.

Spinach
Grow Chesapeake, Hybrid #7, Tyee, Melody, or Old Dominion varieties. Rows should be 12 to 18 inches apart. Plants should be 1 to 4 inches apart, if young plants are to be harvested. If older plants are to be harvested, plant 3 to 6 inches apart. Spinach may be harvested when 6 or more leaves have been formed. Cut the tap root with a knife or hoe just below the lower leaves or cut to 1 inch above the ground.

Specialty Greens
Arugula, cress, corn salad, New Zealand spinach, sorrel and specialty salad mixes all do well in North Carolina. One or more of those greens can be produced throughout the year. Try some of these greens to expand your culinary tastes.

 

2.  Lettuce and Other Salad Greens
This NebGuide discusses different salad greens, their uses and nutritional  value. G95-1268-A

Susan D. Schoneweis, Extension Coordinator--Home/Environmental hort

Lettuce has been an important part of human diets since ancient times. It was
customary for the Romans to precede their gargantuan banquets with refreshing
lettuce salads in the belief that lettuce enhanced the appetite and relaxed the
alimentary canal. It had other uses, too. Dried lettuce juice was used to aid
sleep in Elizabethan times and through World War II lactucarium, a sedative made
from wild lettuce extracts, was used in hospitals¹. Today, lettuce is used as
the main ingredient in most salads and it is joined by a variety of other salad
greens.


Salad greens are easy to grow in the home garden and are an important source of
vitamins and minerals in our diets. Dark green leaves are good sources of
vitamins A and C, iron, folic acid, and calcium. Iceberg lettuce is the most
popular salad green, but there are many other lettuces and salad greens that can
add interest and nutrients to everyday meals.


Lettuce
Lettuce comes in many forms--iceberg or crisphead, bibb or butterhead, Romaine
or Cos, leaf lettuce, and stem lettuce. Lettuce also grows in varying shades of
green, with darker-green leaf types containing greater quantities of vitamins.
Outer leaves of head lettuce are more nutritious than the blanched inner leaves.
There are also red lettuces in every type, although red iceberg lettuce is
rarely found in grocery stores. Red-pigmented lettuces contain more vitamin C
than their green counterparts. Unfortunately, the vitamin C in lettuce is lost
within a few days of storage. By growing your own lettuce, you can plan harvest
and consumption for maximum nutrition.


Many other greens are also good sources of vitamins and minerals. A few grow so
easily most people consider them weeds. Take revenge on their invading presence
in your garden by eating them.


Types of Lettuce and Salad Greens
Crisphead or "iceberg" lettuce with dense, firm heads and crunchy leaves is the
most important commercial type lettuce. Because lettuce is a cool-season crop,
most iceberg lettuce is grown in the cool coastal valleys of California.
Crisphead lettuce is seldom grown in Nebraska because it requires a long, cool
growing season not available here. Plant breeders, however, continually work to
develop shorticultureer season, heat-tolerant cultivars that can be grown in
home gardens. When reading seed catalogs or packets, look for crisphead
cultivars that are ready in about 75 days and tolerate hot weather. For more
nutritious iceberg lettuce, harvest it immature when the leaves are still dark
green, yet crisp.


Leaf lettuce matures quickly, is easy to grow, and is a good type of lettuce for
home gardens. There are hundreds of cultivars available including `Black-Seeded
Simpson', `Oak Leaf', `Grand Rapids', `Ruby Red', and `Red Sails' all of which
mature about 45 days from planting. In contrast to the bright green leaves of
other cultivars, All-American Selections `Ruby Red' and `Red Sails', have
frilled, glossy red leaves.


Bibb or butterhead lettuce, developed by Kentuckian John J. Bibb and often
served at Kentucky Derby breakfasts, produces a loose, soft head². The inner
leaves have an oily or buttery feel. Butterhead cultivars produce high-quality
lettuce that matures slightly earlier than crisp-head cultivars but are less
tolerant of warm weather. `Big Boston', `Bibb', and `Butter Crunch', an
All-American Selection, are popular cultivars. Butterhead lettuce does best in
Nebraska when started early indoors or in coldframes and later set in the garden
as transplants.


The cos or romaine type of lettuce produces an elongated head of stiff, upright
leaves ready about 60 days from planting. Cos lettuce is important in Europe and
is popular in Caesar salads in the United States. In addition to green
cultivars, red cultivars `Rosalita' and `Rouge d 'Hiver' are available from mail
order sources.


Stem lettuce is often listed in catalogs under the name of Celtuce
(CELery-letTUCE). It is grown for its fleshy, elongated stem. The young leaves
are high in vitamin C and are used as "boiling greens". The stem is peeled and
may be eaten raw or it may be cooked like celery.
Spinach (Spinacia oleracea L.) is a cool-season crop used fresh and as a cooked
green. Complete cultural instructions are given in NebGuide G92-1123, Spinach
and Swiss Chard. Spinach grows best under cool temperatures and shorticulture
days, so it should be planted very early in the spring and again in the fall as
temperatures cool.


Other Salad Greens
Cress (Lepidium sativum) comes in four types--common, curled, broadleaf, and
golden. Curly cress, or peppergrass, germinates quickly and is ready to eat in
about 10 days. It forms little stems of frilly green leaves and has a peppery
taste to add zip to dishes. Because it grows so quickly, it is a good plant to
let children grow in pots or flats. It prefers cool weather or a slightly
shady spot. It can also be grown on a sunny window sill in the winter. To
harvest, snip stems with scissors while it is young and tender, as mature
plants tend to become pungent.


Corn salad (Valerianella locusta), also known as Māche, lamb's lettuce, or
fetticus has a mild, nutty flavor. It has rounded leaves that grow slowly into
small rosettes of soft, buttery leaves. It needs a long, cool growing season
and may do best as a fall crop in Nebraska. Since it is quite cold tolerant,
it should overwinter easily in the garden to provide early spring salads.
Harvest whole rosettes if plants need thinning or individual leaves for repeat
harvests.


Endive and escarole (Cichorium endivia) are two popular salad vegetables in
Europe. Endive has curly, deeply cut, lacy leaves with creamy inner leaves.
Escarole has broad, coarse, crumpled leaves that blanch the inner leaves so
they are crunchy yet tender. Cultural practices are the same as for lettuce,
making it an easy crop to grow in the home garden. Like lettuce, they should
be planted early in the spring or as a fall crop as hot weather can make them
bitter.


Arugula or Rocket salad (Eruca vesicaria sativa) leaves have a peppery/sweet
tangy flavor. This green is easy to grow, but the young leaves need to be
harvested frequently for best flavor. It becomes bitter in hot weather, so
plant successive crops early in spring and then again in the fall. If the
plants bloom, harvest the flowers and add the remainder of the plants to the
compost pile as they become bitter. The flowers can be added to salads for a
bit of color.


Mesclun is a mixture of many different salad greens grown and harvested
together for an instant mixed salad. Seed can be purchased from mail order
sources or you can mix your own. Mesclun is harvested when individual leaves
are bite-sized and immature lettuce is usually the main ingredient. Cultivars
in a particular seed mix are chosen for their color, texture, flavor, leaf
size, and shape. Other ingredients, which vary by seed company, include
endive, arugula, oriental greens, radicchio, māche, mustard, and cress. Beet
and chard thinnings may be included. Herbs, such as fennel, sorrel, tarragon,
basil and mints are sometimes included in very small quantities.


Some companies blend their mesclun mixtures for different flavors, such as
tangy or mild. Generally the ingredients need cool growing temperatures and
should be planted in early spring or for a fall garden.


Chicory terminology can be confusing because the same plant is used in three
different ways and cultivars have specific uses. Chicory (Cichorium intybus)
is native to Europe but was brought to the U.S. in the 18th century. It has
naturalized over much of the U.S., including Nebraska. Young plants resemble
dandelions but later the flower stem becomes bristly and bears rigid branches
reaching 18 to 24" tall. The flowers are dandelion-like, sky blue, 1-1 1/2"
wide and close by mid-day. The roots can be dug and roasted and substituted
for or mixed with coffee. Commercially, chicory grown for dried roots is
planted in deep, rich soil in rows 18" apart. The parsnip- like roots are dug
in the fall, roasted and ground.


Witloof chicory, root chicory, or Belgian endive is the same plant treated
differently. There are improved cultivars of Belgian endive/Witloof chicory
available from seed companies. The plants are grown in well-drained, deep,
rich soil. In the fall, the tops are cut off and the roots dug and put into
cold storage for at least three months. After this dormancy period, the roots
are planted in containers 18" deep at 55°F. For high quality white buds or
chicons, keep the newly planted roots in absolute darkness. In about three
weeks the pale yellow leaves will form cone-shaped buds about 6-8 inches long.
Cut off the chicons, discard the spent roots and start another batch. Since
the chicons are grown in the dark, they, like blanched asparagus, have few
vitamins and should not be considered a good source of nutrition.


Radicchio/ Italian chicory is also Cichorium intybus. The beautiful red and
white heads grow to orange- to grapefruit-size. The leaves are slightly bitter
like endive, but sweeten slightly with cooler day temperatures. In the past,
only a portion of radicchio plants made tight heads, but new cultivars,
including some hybrids, have improved uniformity in color and heading.
Radicchio is grown much like head lettuce and needs a long, cool growth
period. Spring crops should be started very early and transplanted to the
garden when 3-4 weeks old. In Nebraska, a fall crop is likely to be of higher
quality than a spring grown crop. Direct seed it in the garden about 85 days
before the first average fall frost. Cover the row with a board or very light
mulch to keep soil temperatures cooler while it germinates.


Long days and/or high temperatures can cause radicchio to bolt, increase in
bitterness and develop tip burn. If temperatures are especially hot in your
area, you may want to start transplants for a fall crop indoors where it is
cool. Radicchio is frost tolerant, but growth will be slow in cold weather.


Edible Salad Weeds
While most people pull and compost weeds in the garden, some exact their revenge
on edible culprits by eating them. Never eat edible weeds which have survived
herbicide treatment. Ask about chemical use before you harvest greens from
locations other than your own lawn or garden.


Purslane (Portulaca oleracea) is one common edible weed that can add valuable
nutrients to the diet. It is high in omega-3 fatty acids and vitamin E. Some
seed catalogs sell cultivated purslane seed that is reported to have better
flavor than the common weed form found in gardens. Purslane has a cool,
citrusy-green flavor. When mixed with other greens, purslane adds crunch and
texture to an otherwise routine salad.


When planting cultivated purslane, wait until the soil has warmed and the
danger of frost has passed. Purslane is a succulent plant with fleshy,
drought-tolerant leaves. It does best in hot weather and full sun.
Dandelions (Taraxacum officinale) are an early spring weed that which are a
good source of vitamins. Instead of spraying dandelions in your lawn, try
eating them. Young leaves can be used raw in salads while older leaves are
usually steamed or braised. The yellow flower petals can also be added to
salads, butters, or sauces to add color and interest. In some parts of the
world, dandelion roots are roasted and used as a coffee substitute.


Improved dandelion seed can be purchased through some seed catalogs. One
French cultivar, `Montmagny', has 8 to 9" leaves that taste like mild chicory.
Commercial cultivars are selected for their large, tender leaves.
Lambquarters (Chenopodium album) can grow more than 4' tall and can be very
difficult to pull or hoe when large. You can save much time and energy by
harvesting it when young and tender. The leaves taste like spinach and the
plant is related to the common cultivated spinach. The undersides of the
leaves have a slightly rough texture so you may prefer it cooked rather than
raw in a salad.


Other Greens
Many other plants, cultivated as well as wild, can be used as greens either
cooked or in salads. Never eat wild greens unless you can positively identify
them as a safe, edible plants.
Seed catalogs are a good source for information on growing and using greens from
the garden. Some companies sell seed for uncommon greens from all around the
world.


General Growing Requirements and Culture
Lettuce and other salad greens have similar cultural requirements. Methods
discussed for growing lettuce can be applied to most other salad greens
discussed in this NebGuide.


Lettuce germinates and grows best at low temperates and will withstand a
moderate freeze. Because of this, it should be planted as soon as the ground can
be worked in the spring. It also does well as a fall crop and can be planted in
August. However, high soil temperatures in the summer can inhibit germination.
You can improve germination of cool-season plants in summer by shading newly
planted seed with a board or light covering of mulch.
Hot weather causes the milky sap to become bitter. High temperatures and long
day lengths also cause lettuce plants to "bolt" or flower and go to seed.
Butterhead and crisphead varieties are especially sensitive to bolting.
Conditions in western Nebraska are more favorable for growing lettuce than in
eastern Nebraska due to cooler night temperatures throughout the growing season.
Suggested periods for planting spring and fall lettuce for different regions in
Nebraska are:

SpringFall

EarliestLatestEarliestLatest
East3/255/17/258/15
Central3/305/57/208/5
West4/55/157/157/25

With the use of floating rowcovers and/or coldframes, salad greens can be
planted in late August and early September and protected from hard freezes in
the fall.


One problem many gardeners have is too much lettuce at one time. Production time
can be extended by making a series of small plantings 10 to 15 days apart.
Crisphead and Romaine lettuces take much longer to reach maturity than leaf
lettuce. Start them from transplants to avoid the hot weather. If transplants
are used, they should be started indoors or in coldframes about March 10 in
eastern, March 15 in central, and March 20 in western Nebraska. They should be
ready for transplanting approximately April 15, April 20, and April 25
respectively. Iceberg lettuce can also be direct seeded like any other lettuce.
As it grows, harvest the crunchy, immature plants to add to salads and to allow
space for the remaining plants to fill in and mature.


Lettuce seed should be sown thinly in rows or wide- row bands about 1 1/2 to 2
feet apart and covered with not more than one-half inch of fine soil. Keep the
soil moist for 10-14 days for good germination. Wide-row planting will use your
garden space more efficiently than traditional narrow rows. It is important to
thin the plants to allow good air circulation between the plants. Thinning also
will help prevent foliar diseases. Leaf lettuce should be thinned to about 3"
between plants in all directions. Allow 6 to 8" between butterhead plants and
10-12" between crisphead and Romaine lettuce plants. An average packet of seed
will sow 50 feet.


Insects and Diseases
Most leafy greens share the same insect pests, including aphids, leafhoppers,
and leafminers. Slugs and sowbugs may also pose problems. Diseases such as downy
mildew and rots brought on by hot, wet weather are also problems. Floating
rowcovers made of spunbonded polypropylene can be used to exclude insect pests.
The fabric comes in varying weights. Heavier types can be used to retain heat
for frost protection while the lightest can be used into the summer to exclude
insects.


To reduce diseases, select cultivars bred to resist or tolerate disease causing
pathogens. Practice good sanitation in the garden and space plants so air can
circulate between them.


Harvesting
In the home garden, lettuce will usually require thinning. You can use the
thinned seedlings in salads from the time they are about 2" tall. When thinning,
pull up entire plants to leave space for others to fill in. If you have more
space and can use more lettuce, transplant the thinnings to another location in
the garden.


Commercially, crisphead lettuce is harvested when the heads are solid and the
tops become yellowish green. However, it also can be harvested when quite young;
before solid heads are formed. Small lettuce plants and mini-heads often have
more crunch than leaf lettuce and more vitamins than the full-size dense heads
of mature lettuce.


Butterhead cultivars are harvested when a loose head is formed. Heads should be
cut at or slightly below the soil surface. Avoid damaging the outer wrapper
leaves. Generally, these are the most nutritious.
Large leaf lettuce plants can be harvested by cutting the leaves off about 1"
above ground. The plants will continue to grow and produce leaves for repeat
harvests. Keep in mind, though, that hot weather will soon make the lettuce
bitter.


Wash all greens in cool water and shake them dry or use a salad spinner. Wrap
lettuce in a damp paper towel and store in a lettuce crisper or plastic bag. Try
to harvest frequently and consume rapidly, as stored lettuce loses much of the
vitamin C content after just a few days in the refrigerator.


References
Sources for less common salad greens
1. Shepherds Garden Seeds, 30 Irene St., Torrington,
CT 06790, phone: (203) 482-3638
2. Stokes Seeds Inc., Box 548, Buffalo, NY 14240-0548,
phone: (716) 695-6980
3. The Cook's Garden, P.O. Box 535, Londonderry,
VT 05148, phone: (802) 824-3400
4. Seeds of Change, 1364 Rufina Circle #5, Santa Fe,
NM 87501, phone: (505-438-8080
5. Johnny's Selected Seeds, Foss Hill Road, Albion,
Maine 04910-9731, phone: (207) 437-4395
¹Rupp, Rebecca, 1987, Blue Corn and Square Tomatoes, Storey Communications,
Inc., Pownal, VT 05261
²Ibid.