CAN I GROW SPINACH?
Spinach is one of the few vegetables with beets and chard that prefers a neutral to alkaline soil (pH 7.0 or above). If your garden soil is sandy and acid, be sure to get a lime recommendation based on a soil test before planting spinach. Spinach is also a heavy feeder. Start by working 2-4 pounds of a complete fertilizer per 100 square feet into the soil at planting time and then side-dress every two weeks or as necessary to keep the plants growing vigorously. Be sure to keep fertilizer 4-6 inches from the base of the plants so as not to burn the roots and water thoroughly immediately after fertilizing.
There is no such thing as putting too much compost in garden soil. Mix at least 2-4 inches of compost in the row before planting. Commercial compost is sometimes little more than slightly decayed wood chips. Check to see that the raw material used to make the compost is mostly unrecognizable before buying it or better yet, make your own.
Spinach thrives in cool weather and short days so it's best to grow it in the fall for most gardeners. Northern gardeners can plant an early spring crop followed by another in midsummer to mature before the first hard freeze. In southern gardens spinach easily tolerates a light frost, especially if it is acclimated. In case of a sudden or hard freeze (below 28 degrees), old blankets or polypropylene frost blankets can save the day and prolong the harvest.
Plant spinach seeds an inch apart in rows 14-18 inches apart and cover the seeds with a 1/2
inch of soil. Keep the soil moist and after the seeds germinate thin them to stand 3-5 inches
apart. Most gardeners like to do this in several passes to determine the strongest plants to
save. Thinning is very important and you must be ruthless in the final analysis or you will
have a congested row of plants that don't size up.
Spinach is thought to be of Persian origin (modern day Iran). It was introduced into Europe
about 1000 AD It wasn't until after the eighteenth century that it began to be cultivated in
the Netherlands, France and England with the Spanish eventually bringing it to the
SEEDS OR PLANTS?
Most gardeners start with seeds but transplants are often available at local nurseries.
Germinating the seeds in the heat of late summer/fall can be a real challenge. The best soil
temperatures for rapid germination (6-7 days) are between 68 and 86 degrees F. Keeping the soil
constantly moist and covering the row with fiber row cover will help to cool the soil and get
the seeds up. Be sure to remove the row cover as soon as the seedlings are visible. If its
still too hot use hoops made from 1/2 inch polyethylene irrigation tubing to lift the row cover
off of the small seedlings. A final spacing of 3-5 inches is best for most varieties. So either
transplant them directly to this spacing or thin them.
Spinach is grown commercially on deep, loam soils. If your garden soil is acid (pH below 7), then be sure to lime the soil based on a soil test to raise the pH to 7.0. Many gardeners opt for raised beds, 6-8 inches above the existing soil, especially if they have a heavy clay soil to deal with. Working 2-4 inches of compost into the soil prior to planting is always a good idea and while you're at it incorporate 2 pounds of a complete fertilizer per 100 square feet.
Make sure the plants are adequately spaced or you will end up with lots of very small leaves
and don't be afraid to side-dress the row with nitrogen to encourage a continual production of
leaves. Ammonium sulfate at 2 tablespoons per foot of row should keep the spinach producing all
season long if applied every two weeks or as needed. Similarly spinach needs lots of water but
it also needs good drainage. Finally just harvest a few leaves at a time from each plant. This
will allow the plants to continue producing all season.
The key to success with spinach begins with getting the plants off to a good start. Plant
the right varieties in a rich, organic soil. Supply lots of moisture and cool the soil
(especially with late summer plantings) and don't be shy about fertilizing. Side-dressing with
a nitrogen fertilizer will work and so will foliar applications of fertilizer like Dyna-Gro.
Check out the Organica Plant Growth Activator and Marine-Gro products, too. Vigorous spinach is
INSECTS & DISEASES
Aphids or plant lice are fond of spinach. Usually a high-pressure water spray will knock
them off or try one of the organic sprays like Burpee's K+Neem. Check with your local
Cooperative Extension Agent for other recommended pesticides.
Caterpillars love spinach, too. Use one of the biological worm sprays (Bacillus thuringiensis) to take out these pests without hazard to people, pets and beneficial insects.
Diseases are also a threat to spinach. White rust, blue mold (downy mildew) and the
soil-borne disease fusarium wilt are the primary pests in this category. White rust is a common
problem during cool, humid conditions. If only a few leaves are infected just remove them.
Where this disease is a common problem, as it is in many areas of the South, check with the
Extension Service for recommended fungicides.
Blue mold can also be treated by removing infected leaves (look for yellow spots on top of the leaf and a grayish-blue mold on the bottom of the leaf) or use a recommended fungicide.
Rotating spinach with unrelated crops for at least three years is the best control for
RECIPES & STORAGE
Fresh spinach is wonderful with blue cheese or ranch dressing, maybe a little bacon,
hard-cooked egg, etc, etc. It's also great sautÃ©ed with a little bacon grease, green onion and
a vinegar hot pepper sauce. Spinach makes a great quiche and also works well in an
Bright, vibrant-looking spinach leaves are not only more appealing to the eye but more nourishing as well. Recent research has shown that spinach leaves that look fully alive and vital have greater concentrations of vitamin C than spinach leaves that are pale in color. The study authors suggest that the greater supply of vitamin C helps protect all of the oxygen-sensitive phytonutrients in the spinach leaves and makes them looking vibrant and alive.
Many people are concerned about the nutrient content of delicate vegetables (like baby spinach) when those vegetables are placed in clear plastic containers in grocery store display cases and continuously exposed to artificial lighting. One recent food study has shown that you don't need to worry about the overall status of antioxidants in baby spinach that has been stored and displayed in this way. In this scientific study, the overall nutrient richness of the baby spinach when exposed to constant light was actually higher than the overall nutrient richness of baby spinach leaves kept in total darkness. The period of time in the study was 9 days, and the spinach was kept at 39°F/4°C (a temperature on the lower end of the scale for most home refrigerators). These findings are good news for anyone purchasing baby spinach in "ready-to-eat" containers.
One new category of health-supportive nutrients found in spinach is called "glycoglycerolipids." Glycoclycerolipids are the main fat-related molecules in the membranes of light-sensitive organs in most plants. They're indispensable for the process of photosynthesis carried out by plants. However, recent lab research in laboratory animals has shown that glycoglycerolipids from spinach can help protect the lining of the digestive tract from damage — especially damage related to unwanted inflammation. You can expect to see more studies about this exciting new category of molecules in spinach and its potential health benefits.
In a recent study on the relationship between risk of prostate cancer and vegetable intake — including the vegetables spinach, broccoli, cauliflower, cabbage, Brussels sprouts, mustard greens, turnip greens, collards, and kale — only spinach showed evidence of significant protection against the occurrence of aggressive prostate cancer. ("Aggressive prostate cancer" was defined as stage III or IV prostate cancer with a Gleason score of at least 7. Gleason scores are based on lab studies of prostate tissue and common tumor-related patterns.) The study authors did not speculate about specific substances in spinach that may have been involved in decreased prostate cancer risk. However, we know that certain unique anti-cancer carotenoids—called epoxyxanthophylls — are plentiful in spinach, even though they may not be as effectively absorbed as other carotenoids like beta-carotene and lutein. You can count on seeing future research on neoxanthin and violaxanthin — two anti-cancer epoxyxanthophylls that are found in plentiful amounts in the leaves of spinach.
Among the World's Healthiest vegetables, spinach comes out at the top of our ranking list for nutrient richness. Rich in vitamins and minerals, it is also concentrated in health-promoting phytonutrients such as carotenoids (beta-carotene, lutein, and zeaxanthin) and flavonoids to provide you with powerful antioxidant protection. Enjoy baby spinach in your favorite salads or make a salad made exclusively of baby spinach. Spinach is one of only three vegetables that we recommend boiling to help reduce its concentration of oxalic acid. We recommend boiling for just 1 minute to minimize loss of nutrients and flavor. For more on the Healthiest Way of Cooking Spinach, see the How to Enjoy section below.
Foods belonging to the chenopod family—including beets, chard, spinach and quinoa—continue to show an increasing number of health benefits not readily available from other food families. The red and yellow betalain pigments found in this food family, their unique epoxyxanthophyll carotenoids, and the special connection between their overall phytonutrients and our nervous system health (including our specialized nervous system organs like the eye) point to the chenopod family of foods as unique in their health value. While we have yet to see large-scale human studies that point to a recommended minimum intake level for foods from this botanical family, we have seen data on chenopod phytonutrients, and based on this data, we recommend that you include foods from the chenopod family in your diet 1-2 times per week. In the case of a leafy food like spinach, we recommend a serving size of at least 1/2 cup, and even more beneficial, at least one full cup.
We all know that Popeye made himself super strong by eating spinach, but you may be surprised to learn that he may also have been helping to protect himself against inflammatory problems, oxidative stress-related problems, cardiovascular problems, bone problems, and cancers at the same time.
Even though virtually all vegetables contain a wide variety of phytonutrients—including flavonoids and carotenoids—spinach can claim a special place among vegetables in terms of its phytonutrient content. Researchers have identified more than a dozen different flavonoid compounds in spinach that function as anti-inflammatory and anti-cancer agents. (Some of these substances fall into a technical category of flavonoids known as methylenedioxyflavonol glucuronides.) The anticancer properties of these spinach flavonoids have been sufficiently impressive to prompt researchers to create specialized spinach extracts that could be used in controlled laboratory studies. These spinach extracts have been shown to slow down cell division in human stomach cancer cells (gastric adenocarcinomas), and in studies on laboratory animals, to reduce skin cancers (skin papillomas). A study on adult women living in New England in the late 1980s also showed intake of spinach to be inversely related to incidence of breast cancer.
Excessive inflammation, of course, typically emerges as a risk factor for increased cancer risk. (That's why many anti-inflammatory nutrients can also be shown to have anti-cancer properties.) But even when unrelated to cancer, excessive inflammation has been shown to be less likely following consumption of spinach. Particularly in the digestive tract, reduced inflammation has been associated not only with the flavonoids found in spinach, but also with its carotenoids. Neoxanthin and violaxanthin are two anti-inflammatory epoxyxanthophylls that are found in plentiful amounts in the leaves of spinach. While these unique carotenoids may not be as readily absorbed as carotenoids like beta-carotene or lutein, they still play an important role in regulation of inflammation and are present in unusual amounts in spinach.
Decreased risk of aggressive prostate cancer is one health benefit of spinach consumption that should not be overlooked when talking about the anti-cancer properties of spinach. "Aggressive prostate cancer" is defined as stage III or IV prostate cancer which carries with it a Gleason score of at least 7. (Gleason scores are prostate cancer rating measurements that require lab studies of prostate tissue and evaluation of common tumor-related patterns.) Interestingly, in a recent study that evaluated possible prostate cancer-prevention benefits from a variety of vegetables including spinach, broccoli, cauliflower, cabbage, Brussels sprouts, mustard and turnip greens, collards, and kale — only spinach showed evidence of significant protection against the occurrence of aggressive prostate cancer.
Most of the flavonoid and carotenoid nutrients found in spinach that provide anti-inflammatory benefits provide antioxidant benefits as well. Given the fact that spinach is an excellent source of other antioxidant nutrients — including vitamin C, vitamin E, vitamin A (in the form of carotenoids), and manganese —as well as a very good source of the antioxidant zinc and a good source of the antioxidant selenium—it's no wonder that spinach helps lower risk of numerous health problems related to oxidative stress. Our blood vessels, for example, are especially susceptible to damage from oxidative stress, and intake of spinach has been associated with decreased risk of several blood vessel-related problems, including atherosclerosis and high blood pressure. (Interestingly, the blood pressure benefits of spinach may be related not only to its antioxidants, but also to some of its special peptides. Peptides are small pieces of protein, and researchers have discovered several peptides in spinach that can help lower blood pressure by inhibiting an enzyme called angiotensin I-converting enzyme.)
Two of the carotenoids that are especially plentiful in spinach — lutein and zeaxanthin — are primary antioxidants in several regions of the eye, including the retina and the macula. Although we haven't seen specific studies on spinach intake and prevention of eye-related problems like macular degeneration, we have seen studies showing that human blood levels of lutein can be increased by consumption of spinach in everyday amounts. We've also seen at least one group of researchers suggesting that spinach has a likely role to play in prevention of eye problems, including age-related macular degeneration.
The wealth of vitamin K provided by spinach is important for maintaining bone health. Vitamin K1 helps prevent excessive activation of osteoclasts, the cells that break down bone. Additionally, friendly bacteria in our intestines convert vitamin K1 into vitamin K2, which activates osteocalcin, the major non-collagen protein in bone. Osteocalcin anchors calcium molecules inside of the bone. All of these vitamin K-related mechanisms point to the importance of vitamin K-rich foods for bone health, and it is difficult to find vegetables that are richer in vitamin K than spinach. (On our World's Healthiest Foods list, only kale provides more micrograms of vitamin K per cup.) Spinach is also an excellent source of other bone-supportive nutrients including calcium and magnesium.
So while spinach probably won't make you super strong the minute you eat it, as it did for Popeye, it will promote your health and vitality in many other ways. It seems like Popeye was pretty smart after all.
Calorie for calorie, leafy green vegetables like spinach with its delicate texture and jade green color provide more nutrients than any other food. Although spinach is available throughout the year, its season runs from March through May and from September through October when it is the freshest, has the best flavor, and is most readily available. Spinach belongs to the same family (Amaranthaceae-Chenopodiaceae) as Swiss chard and beets and has the scientific name, Spinacia oleracea. It shares a similar taste profile with these two other vegetables, having the bitterness of beet greens and the slightly salty flavor of Swiss chard.
Popeye popularized spinach, but it's too bad he ate it out of a can. Fresh spinach retains the delicacy of texture and green color that is lost when spinach is processed. Raw spinach has a mild, slightly sweet taste that can be refreshing in salads, while its flavor becomes more acidic and robust when it is cooked.
There are three different types of spinach generally available. Savoy has crisp, creased curly leaves that have a springy texture. Smooth-leaf has flat, unwrinkled, spade-shaped leaves, while semi-savoy is similar in texture to savoy but is not as crinkled in appearance. Baby spinach is great for use in salads owing to its taste and delicate texture.
Spinach is thought to have originated in ancient Persia (Iran). Spinach made its way to China in the 7th century when the king of Nepal sent it as a gift to this country. Spinach has a much more recent history in Europe than many other vegetables. It was only brought to that continent in the 11th century, when the Moors introduced it into Spain. In fact, for a while, spinach was known as "the Spanish vegetable" in England.
Spinach was the favorite vegetable of Catherine de Medici, a historical figure in the 16th century. When she left her home of Florence, Italy, to marry the king of France, she brought along her own cooks, who could prepare spinach the ways that she especially liked. Since this time, dishes prepared on a bed of spinach are referred to as "a la Florentine."
Spinach grows well in temperate climates. Today, the United States and the Netherlands are among the largest commercial producers of spinach.
Choose spinach that has vibrant deep green leaves and stems with no signs of yellowing. The leaves should look fresh and tender, and not be wilted or bruised. Avoid those that have a slimy coating as this is an indication of decay.
Do not wash spinach before storing as the exposure to water encourages spoilage. Place spinach in a plastic storage bag and wrap the bag tightly around the spinach, squeezing out as much of the air as possible. Place in refrigerator where it will keep fresh for up to 5 days.
Avoid storing cooked spinach as it will not keep very well.
Spinach should be washed very well since the leaves and stems tend to collect sand and soil. Before washing, trim off the roots and separate the leaves. Place the spinach in a large bowl of tepid water and swish the leaves around with your hands as this will allow any dirt to become dislodged. Remove the leaves from the water, empty the bowl, refill with clean water and repeat this process until no dirt remains in the water (usually two to three times will do the trick). Do not leave spinach soaking in the water as water-soluble nutrients will leach into the water.
Spinach sold in bags has been pre-washed and only needs to be rinsed. If you are going to use it in a salad, dry it using a salad spinner or by shaking it in a colander.
Spinach is only one of three vegetables we recommend boiling to free up acids and allow them to leach into the boiling water; this brings out a sweeter taste from the spinach. Discard the boiling water after cooking; do not drink it or use it for stock because of its acid content.
Use a large pot (3 quart) with lots of water and bring to a rapid boil. Add spinach to the boiling water and boil for 1 minute. Begin timing as soon as you place the spinach in the pot if you are using 1 pound or less of spinach. If you are cooking larger quantities of spinach bring the water back to a boil before beginning timing the 1 minute. Do not cover the pot when cooking spinach. Leaving the pot uncovered helps to release more of the acids with the rising steam. Research has shown that the boiling of spinach in large amounts of water helps decrease the oxalic acid content.
Remove spinach from pot, press out liquid with a fork, place in a bowl, toss with our Mediterranean Dressing, and top with your favorite optional ingredients.
Virtually all municipal drinking water in the United States contains pesticide residues, and with the exception of organic foods, so do the majority of foods in the U.S. food supply. Even though pesticides are present in food at very small trace levels, their negative impact on health is well documented. The liver's ability to process other toxins, the cells' ability to produce energy, and the nerves' ability to send messages can all be compromised by pesticide exposure. According to the Environmental Working Group's 2014 report "Shopper's Guide to Pesticides," conventionally grown spinach is among the top 12 fruits and vegetables on which pesticide residues have been most frequently found. Therefore, individuals wanting to avoid pesticide-associated health risks may want to avoid consumption of spinach unless it is grown organically.
Several national recalls of spinach-containing products between 2006-2013 have raised consumer concerns about the risk of spinach contamination with E. coli bacteria. Of special concern have been Shiga toxin-producing E. coli (STEC), including E. coli 0157:H7. Thorough washing of contaminated spinach cannot remove E. coli 0157:H7. However, as summarized by the U.S. Food and Drug Administration (FDA), "Cooking fresh spinach at 160°F (71°C) for 15 seconds will kill any E. coli 0157:H7 present." The cooking method we recommend on our website for spinach—a quick boil for approximately 1 minute—greatly exceeds this safety standard.
Because many people enjoy spinach in raw form (especially baby spinach), we are often asked about the level of risk involved with consumption of raw spinach. While we have not seen enough data to provide you with an exact risk level here, there is definitely some level of risk involved—although it might be very small—with consumption of raw spinach. If your goal is to remove this risk entirely, your best approach is to follow our quick boil cooking method for spinach.
In the case of certified organic raw spinach (and other certified organic raw vegetables), there is one regulation working to help lower contamination risk: raw animal manure cannot be used less than 120 days prior to harvest of a certified organic food if the food (like spinach) has an edible portion that comes into contact with the soil or soil surface. This restriction on the use of raw animal manure can help prevent crops like spinach from being contaminated with bacteria like E. coli 0157:H7. In the case of non-organic raw spinach, there can also be reduction of risk due to irradiation of the spinach—a practice allowed by the FDA since 2008. (Since irradiation is a prohibited practice in the production of certified organic foods, however, certified organic raw spinach is not irradiated.)