Spinach

Spinach isn’t just for cartoon sailors! This delicious member of the amaranth family can hold its own in your garden, on a window sill, or growing on a balcony. Cousin to beets, quinoa, and chard, spinach lives up to its reputation as a nutritional powerhouse, but not for the reason you think.

Cartoonists weren’t exaggerating when they showed how spinach pumped up our beloved sailor man, but iron isn’t the reason. A single cup of fresh spinach provides 56% of the RDA for Vitamin A, 15% folic acid, 14% Vitamin C, 13% manganese, and 181% Vitamin K, and all for less than 7 calories. Spinach only contains 5% of the RDA for iron, but it does provide high levels of carotenoids, which helps prevent cataracts, and many other important nutrients.

Spinach

As children, many of us cringed at the mere mention of spinach. Part of that was due to canned and frozen varieties being cooked into a stringy, slimy, green ooze. It also reflected the fact that a child’s taste buds are more sensitive to bitterness that an adult’s. Now that we are older and wiser, however, we can truly enjoy the crisp, refreshing, delicious flavor of a spinach salad. And freshness is the key. In fact, while working as a USMC Family Childcare Provider, I overheard a conversation that no one expects to hear: one toddler admonishing another toddler to not eat so many spinach leaves because it would damage the plant! You can read more about that here.

Spinach seeds & leaves

Much of the spinach sold in American grocery stores is the light to dark green, smooth, oblong- or triangular-shaped leaf variety. There are also varieties with distinctly crinkled leaves. This characteristic earns them the name ‘savoy’, after a cabbage with similar tendencies. Savoy spinach varieties produce thicker, more rounded leaves. There are also crosses between the two, called semi-savoy. Now, if you have ever planted spinach, you know that the seeds are rather large, especially when compared to other greens. Spinach seeds come in two forms: prickly and smooth. You might expect the smooth seeds to produce smooth leaves and vice versa, but it’s just the opposite. Smooth seeds tend to produce crinkled (savoy) leaves, while prickly seeds tend to produced smooth leaves. ​

​Spinach lifecycle

Spinach (Spinacia oleracea) is an annual that tends to bolt, or go to seed, as soon as temperatures rise. Bolting makes the leaves lose their flavor, but it can also provide you with seeds for your next spinach crop. You can collect your own seeds, as long as you do not plant hybrids. [Hybrids generally do not produce plants that look or taste like the parent.] You can also let them fall where they will, as I do. They always seem to find the spots that suit them the best.

Most varieties of spinach are dioecious, which means there are male plants and female plants. The ‘Bloomsdale’ variety is monoecious, which means each plant is both male and female and can self-pollinate. Spinach grows relatively fast. You can have harvestable spinach within 3 weeks, so you may want to stagger your plantings for a continuous crop. This is called succession planting. Or, you can allow your spinach plants to go to seed naturally, which can provide a perpetual bed of spinach for most of the year, plus the flowers provide nectar and pollen for many beneficial insects.

Spinach with flowers (Rasbak) CC BY-SA 3.0

Spinach pests & diseases

Spinach is susceptible to many fungal diseases, including downy mildews, rust, fusarium wilt, and Pythium. The Rhizoctonia parasite can also attack your spinach plants. Aphids, crickets, earwigs, flea beetles, cutworms, darkling beetles, bulb mites, leaf miners, loopers, nematodes, seedcorn maggots, slugs and snails, wireworms, whiteflies, rabbits, and chickens can also wreak havoc on your spinach plants. Personally, I conduct a weekly leaf inspection of my spinach and beet plants. A quick peek under each leaf makes it easy to wipe off whitefly eggs before they can hatch. These eggs look like clusters of tiny white rectangles.

How to grow spinach 

Spinach can be added to flowerbeds, next to walkways, at the base of peas and other climbing plants, and anywhere else these fast growing greens will look nice. As a cool season crop, spinach can be started directly in the ground anytime between late August through April in warmer regions. Spinach prefers sunny locations during cooler weather and some shade protection during hotter months. You can also grow it indoors, in containers, year round, if you have a sunny window or grow lights. Containers should be at least 8” deep.

Seeds should be planted 1/2” deep and kept moist until germination occurs. Seedlings should be transplanted at a time when they are most likely to survive, which means when temperatures are not scorching. Transplants should be spaced 8 to 10” apart. The same is true for seeds sown directly in the ground. You can make your soil more conducive to spinach by topping dressing the bed with some aged compost ahead of time. Spinach favors lighter, sandier soil than we tend to have here and it is a heavy feeder. You can add nutrients by side-dressing, which means placing aged compost around and next to plants once they are in place. As you water, the nutrients will leach into the root zone and be absorbed by the plants. Spinach prefers a pH of 6.5 to 7.5. Spinach plants have shallow roots, so be sure to water regularly, especially as temperatures begin to rise.

Some varieties of spinach perform better when grown in the fall, while others prefer spring. I keep seeds of several varieties handy so that I can maintain a constant supply of fresh spinach throughout most of the year. Be sure to read the packet before you start planting.

Spinach substitutes

Since spinach only grows successfully in hot regions during during the cooler months, you can grow other plants during the summer that provide similar taste and nutrition. These plants are:

• New Zealand spinach (Tetragonia tetragonioides)
• Malabar spinach (Basella alba)
• Lambs quarters (Chenopodium giganetum)

Spinach history & trivia

Spinach was first grown in Persia, around 500 B.C. The “Persian vegetable”, as it was called, was brought to China in the 7th century. Two hundred years later, spinach seeds made their way to Italy. Florence’s Catherine de’ Medici loved spinach so much that foods served on a bed of spinach became known as “Florentine”. Another five hundred years pass before spinach has a home in western Europe, appreciated for appearing in early spring, when food is scarce, and by not breaking any religious food rules. Spinach was even included in the first known English cookbook in 1390!