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Garden Journal

New Zealand spinach variety is rich in Vitamin K

July 30, 2014

Where would we be without chickens? In 1929, Danish scientist Henrik Dam fed chickens a cholesterol-depleted diet that made the birds very sick. Even when purified cholesterol was added back into their diet they remained sick. Henrik Dam realized that along with the cholesterol, he had removed a second compound with a coagulant effect on the body.  Oddly this vitamin was called “Vitamin K” simply because it was first reported in a German journal where it was called “Koagulationsvitamin.”

Luckily there is an easy to grow garden vegetable that delivers 278 percent of our daily requirement of elusive Vitamin K. This is Tetragonia (Tetragonia tetragonioides), better known as New Zealand spinach.

Tetragonia was discovered in Queen Charlotte’s Sound, New Zealand, during the 1770 voyage of Capt. James Cook.  He used it cooked and pickled to help prevent scurvy.

Although the triangle-shaped leaves of New Zealand spinach taste remarkably like regular spinach (Spinacia oleracea) the two plants are unrelated.  And that’s a good thing, because regular garden spinach tends to become bitter and bolt or go to seed during warm weather, but New Zealand spinach actually thrives during hot summers.

Few pests bother New Zealand spinach.  The only possible downside to growing this is that New Zealand spinach, like many greens, has oxalic acid in the leaves, which does not appeal to every taste.

New Zealand spinach is a large, spreading plant with small, two-inch pointed leaves. And it is the leaves that hold the vitamins. You can cut entire bunches of leaves or hand pick individual young leaves without killing the plants.

Since you are growing this for its leaves you can really plant it any time after the danger of frost has passed. July and August are not too late to put some New Zealand spinach into bare spots in the garden.

The plants flower at the base of the leaves.

You can save seeds for next year because the flowers are self-pollinating and the seeds will grow true to type.

Plant New Zealand spinach in full sun in well-drained soil. It does best with a soil pH of 6.8 to 7.0. For best results, soak seeds for 24 hours before planting.

Sow the seeds one-half inch deep and two to four inches apart in rows two feet apart. Once your plants are three to four inches tall, thin them to stand 12 to 18 inches apart.

Keep the seedbed moist, but not soggy, until the seeds germinate. If you don’t want rows, you can plant New Zealand spinach in hills the way some gardeners plant corn or squash. Plant four or five seeds per hill and thin to just one or two plants. Space the hills two to three feet apart.

For best flavor, keep picking the leaves throughout the season. Never let the soil dry out, because even though New Zealand spinach is drought tolerant, the leaves will not be as tender or flavorful if the plants are stressed for water.

To hold in soil moisture, you can lay down a thick mulch of straw or grass clippings.

After a few weeks of growth you may want to side dress the plants with a good organic fertilizer. Like all greens, they respond well to compost tea or liquid seaweed fertilizer.

For a vitamin-rich vegetable, plant New Zealand spinach in the heat of summer. The leaves can go right into a tossed salad or be sauteed with cannellini beans in olive oil and garlic for greens and beans. Or even put the leaves on the barbecue, or as they almost certainly don’t say “Put some greens on the barbie.”   New Zealand spinach is, after all, one of the few cultivated vegetables originating in Australia and New Zealand.  Enjoy the warm weather New Zealand spinach, discovered with the help of Captain Cook, filled with Vitamin K, discovered with the help of chickens.

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