spinach (20796 bytes)

2002: Year of the Spinach

line4.gif (1411 bytes)

The National Garden Bureau Celebrates 2002 As The Year of The Spinach

Forget Popeye! Spinach contains many more nutrients than just iron. Actually, the amount of iron in spinach comes way down the list after vitamins A and C, thiamin, potassium and folic acid (one of the B complex vitamins). Dark green leafy vegetables, like spinach, contain lutein and zeaxanthin, both carotenoids. Studies show carotenoids help your eyes stay healthy as you age by preventing macular degeneration and the formation of cataracts. Vitamins A and C, both antioxidants, keep your cardiovascular system healthy, thereby reducing the risk of strokes and heart attacks. Folic acid is essential for the production of red blood cells and for normal growth, and may reduce the risk of certain cancers. It's particularly important for pregnant women.

All of that in a decorative vegetable that tastes great whether you eat it raw in salads or cooked in innumerable dishes. It is particularly tasty and has the highest nutrient levels when you harvest it from your own garden. The flavor has a sharp, almost peppery, overtone.


A BIT OF HISTORY

Spinach has been a diet staple for centuries. Originating so long ago in Asia that the exact location is unknown, the National Garden Bureau found it was introduced into Europe in the 15th century. Americans, such as Thomas Jefferson, grew it as far back as the 19th century. Then, as now, two types of spinach seeds exist: round and prickly. The seed type does not dictate whether the spinach leaf will be smooth or crinkled, and, interestingly, savoy (crinkled) spinach most often has smooth round seeds, while smooth-leaf varieties have prickly seeds. Asian types are primarily prickly seeded and have triangular shaped leaves. The worldwide volume of Asian type spinach is tremendous.

Breeding work with spinach began in earnest in the early part of the 20th century when breeders started selecting and hybridizing varieties with more disease resistance and those that would be slower to bolt (go to seed) in hot weather. One of the best-known varieties came from that period: 'Bloomsdale Long Standing,' a slow-bolting, savoyed plant still grown today. It is a monoecious plant, which means that the flower contains both male and female parts. By self-pollinating the plant over a number of generations, each time saving the seeds of the best performers and self-pollinating them, the breeders (the Dutch team of Zwaan and Van der Molen) eventually ended up with a pure, inbred line.

The search for varieties resistant to mildews and viruses, as well as to bolting, continued through the 20th century. Such varieties as 'Viking' in 1935 and 'America' in 1952 were successful enough to win All-America Selections awards, although they are seldom grown today. In 1955, researchers at the United States Department of Agriculture introduced the first hybrid spinach resistant to downy mildew, called by the uncatchy name of 'EH7.' One of the most popular hybrids of the time, 'Melody,' introduced by Royal Sluis, won an AAS award in 1977; the savoy-leaf hybrid grows very fast, is slow to bolt in hot weather, and does well as both a spring and fall crop. Don't bother to save seeds of F1 hybrids, such as 'Melody,' because seeds from the hybrids do not breed true; in other words, you won't get 'Melody' from those seeds if you sow them the following season or year.

WHAT'S IN A NAME?

The botanical name for spinach is Spinacia oleracea. Spinacia comes from the Latin word for spine and refers to the prickly seed coat. The species name, oleracea, refers to a plant that is edible. True spinach has varying leaf shapes and textures. There are two major types of leaf textures. Smooth-leaf spinach produces light to dark green leaves with an oblong shape. The leaves of savoy spinach are thicker, rounder, usually darker green, and range from very crinkled to only somewhat (the latter known as semi-savoyed). Breeders have crossbred both types so you may find a crinkled, savoyed leaf with the shape of a smooth-leaf type. An advantage one has over the other is that smooth-leaf types are easier to clean.

Because spinach goes to seed quickly in the longer, hot days of summer, gardeners can substitute two spinach-like greens that like hot weather. The leaves of both Malabar spinach (Basella alba) and New Zealand spinach (Tetragonia tetragonioides) taste similar to true spinach, although they are in completely different families. Malabar spinach is a vining plant, which grows quickly to about 20 feet; you need to start the seeds indoors if you live in a northern region. New Zealand spinach is a shrubby plant, which spreads up to 2 feet; soak the seeds overnight before sowing, indoors or out.

START YOUR CROP INDOORS OR OUT

Spinach, like lettuce, is a cool-weather crop; heat and long days cause the plants to bolt, which means they produce flowering stems and seeds. Plants that bolt lose their flavor. The cooler, shorter days of spring and fall are the best times to grow spinach. To plan your garden, sowing seed to harvest is from 30 to 45 days for spinach.

For a spring harvest, you should sow seeds as soon as the soil in the garden is workable, which means February, March, or April, depending on the region of the country in which you live. Unlike other vegetables that take a long time to mature, such as tomatoes and peppers, spinach does not need to get a head start on the growing season by being started indoors. However, the National Garden Bureau recommends sowing the seeds indoors for a few good reasons. First, if you plan to grow a crop in containers, it's easier to plant seedlings at the correct spacing than to thin out your sowing later. It's also easier to incorporate spinach in a flower garden if you set out transplants instead of sowing seeds. And, to start seeds for a fall harvest, you need to sow them near the beginning of August, which is notoriously hot in most areas; sowing seeds indoors provides them with cooler soil and temperatures in which to germinate.

SOWING INDOORS
Start seeds about 3 weeks before transplanting outdoors. Use flats or individual pots made of peat or plastic. There is a definite advantage to peat pots because they go right in the ground with the seedlings since they biodegrade.

Fill the containers with a germinating mix; water the mix and let it drain. Create one or two rows in the flats by making slight depressions with a ruler or your finger. Sow the seeds evenly about 1 inch apart and cover them with 1/4 inch of the mix. If you sow in pots, place two to three seeds in a shallow center hole and cover with the mix.

Settle the seeds by watering with a mister. To keep the mix moist while the seeds germinate, put the flats or pots in ordinary plastic bags, closed with twist ties.

When seedlings emerge in 7 to 10 days, remove the plastic bags and place the containers on a windowsill in direct sun or in a fluorescent-light garden.

Thin out the seedlings when they reach 2 inches in spread, leaving 2 to 3 inches between them in flats, or one seedling per pot. To thin, simply snip off the unwanted seedlings at soil level.

In about a week, transplant the seedlings outdoors into the garden or containers. Transplant on an overcast, calm day. Set the seedlings in the ground at the same level they were growing in the flat. Don't unpot seedlings sown in peat pots. Plant pots into soil and completely cover the rims, which dry out quickly. Space transplants 6 to 8 inches apart. Water well.

SOWING OUTDOORS

Whether you plant in a vegetable or flower garden, prepare the soil before sowing. Dig the soil to a depth of 6 to 8 inches and incorporate organic matter, such as compost or dried manure. Spinach prefers a light, rather sandy soil with a pH between 6.5 and 7.5; if your soil tests more acidic (pH below 6) add lime at the recommended rate to raise the pH. Since lime reacts slowly, it may take more than one growing season to raise the pH.

Spinach is not a long-lasting crop, so plan to sow a little every week to 10 days for three to four weeks. You want the last sowing to mature before long days and hot weather (above 75 degrees Fahrenheit) set in; count backwards from May, June, or July (depending on where you live) to determine when you should make that final spring planting. Most spinach varieties take 4 to 6 weeks to mature, but you can begin harvesting leaves when the plants are younger.

In the vegetable garden, sow seeds thinly in rows 12 to 15 inches apart. If you prefer to sow in square-foot blocks, scatter seeds across the surface. Sow seeds among rows of peas, if you want, to take advantage of the light shade the pea vines provide and to make good use of all your garden space. In a flower garden, to use as an edging, for example, sow in a row; to use as fillers or accents among young perennials, make a shallow hole and set two to three seeds in it. Cover seeds with 1/4 to 1/2 inch of soil or compost, firm it down to make sure the seeds are in contact with the soil, and water well. After the seeds germinate and produce a few true leaves, thin the plants as necessary to space them 6 to 8 inches apart.

GROWING IN THE GARDEN

Spinach is a heavy feeder and needs a lot of nitrogen while it grows. Nitrogen, which helps all plants produce abundant, healthy foliage, is listed first on packages of fertilizer; 6-4-1 (this refers to the grade or analysis of the fertilizer which is the minimum guarantee of the percentage of total nitrogen, available phosphoric acid, and water soluble potash in the fertilizer) for example, indicates the fertilizer contains 6% nitrogen, 4% phosphorus and 1% potassium (3-2-1 ratio). Fish emulsion and cottonseed meal provide organic, readily usable sources of nitrogen for the plants. Provide initial fertilizer by incorporating a fertilizer into the soil before planting. Then feed the plants after you thin them and again in a couple of weeks by side-dressing: Spread fertilizer around the base of the plants or along the length of the row and work it into the soil by digging very lightly or watering. If you use fish emulsion, simply dilute it in a watering can and pour it on the soil around the plants. (You may want to hold your breath to avoid the very pungent odor, which disappears after a day.)

Spinach grows on shallow roots, so don't dig vigorously around it. Cultivate gently to remove weeds, which compete for nutrients and water.

Water frequently to keep up with the fast growth of the plants.

EXTENDING THE HARVEST

Spinach is one of many vegetables you can grow for a fall harvest. (Others include lettuces, peas, turnips and radishes.) Select a slightly shaded area in the garden to sow the seeds, perhaps a row filled with bush or pole beans or tomatoes, or a row where you plan to sow peas. The shade provides some protection for the soil and the plants from the intense heat of summer. Near the beginning of August, sow seeds as you did for your spring crop or start them indoors. Keep the soil evenly moist and, after germination, water the plants regularly. Good varieties for fall crops include hybrids 'Avon,' 'Indian Summer,' 'Melody,' 'Razzle Dazzle' and 'Tyee.'

WINTER HEAD START

Take advantage of spinach being so hardy and such a cool-weather vegetable by starting it so that it winters over in the garden. In September, and up to November in mid-south or southern regions, sow seeds in an empty space in the garden or in a cold frame. The seeds will germinate and begin to grow before the ground freezes. If the weather stays mild, you may find yourself harvesting leaves and plants at Thanksgiving or even later. If the plants are small when cold weather arrives, however, do not pick leaves unless you grow the plants in a cold frame. You may be able to gather leaves all winter from plants in a cold frame.

When the ground freezes, cover the planting in the open garden with a row cover or a mulch of hay. As temperatures start to warm up in early spring, uncover the plants and care for them as you would any spring crop. Water and fertilize. Overwintered plants tend to be larger, with more spread, than those started in spring. 'Bloomsdale Long Standing,' 'Cold Resistant Savoy' and 'Tyee' make good winter plantings.

HARVESTING AND PRESERVING

Harvest spinach the way you do leaf lettuce, by cutting individual leaves starting with the outer ones, or by cutting the whole plant. If you want to incorporate only a few leaves in a mixed salad or a dip (delicious spinach-artichoke dip, for example), cutting leaves makes sense; the plant will continue to produce new leaves for awhile. To use as a side dish or in a main-dish recipe, harvest the entire plant; cut about an inch above the crown, where leaves join roots; the plant will put out new leaves to extend your harvest.

Wash spinach leaves well - soil is not tasty!

Spinach is highly ethylene sensitive. To reduce leaf yellowing do not refrigerate with apples, melons or tomatoes.

Now, about kids (and more than a few adults) and their notorious dislike for spinach! Entice them in a number of ways. First, get them to grow their own, either in a section of your main garden or in a couple of containers. Homegrown, freshly picked spinach tastes far better than store-bought, packaged spinach. Let the kids mix their own blend of salad greens, combining green and red leaf lettuces with smooth and savoyed spinach. Uncooked spinach often goes over better than cooked, so slip a few leaves into your regular salad recipe. Disguise the slightly metallic taste of cooked spinach by spicing it up with crumbled bacon, minced garlic or grated cheese. Put a few chopped leaves into soups just before serving. Spinach is about 90 percent water, which is the reason you don't need to put it in extra water to cook; the moisture left on the leaves after rinsing and cleaning them is sufficient.

The best way to preserve spinach for winter use is to freeze it. Rinse the leaves well, place them in a resealable plastic bag and blanch them in the microwave (600-700 watts) for 1 minute, then place in the freezer. Spinach loses too much of its vitamin content if you blanch it in boiling water.

RAISING SPINACH IN CONTAINERS

The number one reason for growing spinach in containers is so you actually get the harvest. Rabbits and other four-footed creatures like spinach but they cannot reach it if you grow it in pots up on a deck or steps. The second reason is space; if you live in a townhouse or apartment, in suburb or city, a balcony or rooftop may be your only access to a garden.

Grow spinach in 6-inch to 12-inch diameter containers, in windowboxes or rectangular planters. Because the soil in small pots dries faster, select larger containers to cut down on how frequently you need to water.

To plant spinach with decorative, flowering plants, combine it with annuals or herbs that prefer or can survive in fairly moist soil. Plant it with summer-blooming annuals, such as petunias or marigolds, which keep the container attractive through midsummer after you have harvested the spinach. To do that successfully, space the spinach plants far enough apart that you can tuck in young, small transplants of the summer-bloomers as the weather warms up. The transplants take over as your spinach harvest comes to an end. Contrast the large, somewhat coarse leaves of savoyed spinach with more delicate-looking curly-leaf parsley, which grows well in cool weather. Set up a tepee for pole beans in a large container and plant spinach around it; by the time the weather is warm enough to sow the beans, the spinach season will be waning.

Some of the smaller spinach varieties, such as 'Baby's Leaf Hybrid' and 'Melody,' are particularly good in containers.

DISEASES AND PESTS

Downy mildew (Blue mold), in many forms, is the primary disease you need to watch out for. A fungal disease, downy mildew produces slightly yellow or chlorotic lesions of irregular shape on the top surface of the leaves and purplish sporulation on the underside. To prevent it, space plants for good air circulation and, when you water, wet the ground around the plants not the foliage itself. To help avoid soil borne diseases such as Rhizoctonia, Pythium or Fusarium, rotate the plantings each year; in other words don't sow spinach in the same row or bed every year. Look for resistant varieties such as 'Melody,' 'Nordic IV,' 'Olympia,' 'Tyee' and 'Wolter' (a Dutch hybrid).

Viruses can also be problems. Aphids spread them, so to protect your crop, be on the lookout for these small, flying green or black insects; wash them off with a hard spray of water from the garden hose.

Other than aphids, pest problems are negligible, unless, of course, you include rabbits!


The 'Year of the Spinach' is provided as a service from the National Garden Bureau. The use of this information is unrestricted. Please credit the National Garden Bureau as the source. The National Garden Bureau is a non-profit organization and recognizes the seed company members that generously donate funds for this educational program. 2003 will be the 'Year of the Bean and the Poppy'.

Information and Photograph courtesy of National Garden Bureau.

Back to National Garden Bueau Selections

Back to What's New

Back to Home

 

 

Ask a Colorado Master Gardener | Calendar | Children | Container GardeningCSU Fact Sheets
Credits | Diseases | FAQ | Flowers | Fruits | Gardening | GlossaryHouseplants | Insects & Pests
Lawn & Grasses | Links | New to Colorado | PHC/IPM | Soil | Shrubs | Trees
Vegetables | Water Gardening | Weeds | What's New | Who We Are | Xeriscape

Search

line4.gif (1411 bytes)

Contact Us | Disclaimer | Equal Opportunity

CSU/Denver County  Extension Master Gardener 2010
888 E. Iliff Avenue,  Denver, CO 80210
(720) 913-5278

E-Mail: denvermg@colostate.edu  

Date last revised: 01/05/2010