Growing Malabar and New Zealand Spinach

Vegetable crops are broadly defined as being either cool season or warm season. Spinach (Spinacea oleracea) is a cool-season crop that just won't produce in the heat of our Pennsylvania summers. If you like spinach, there are two alternatives that will actually thrive in the heat. New Zealand spinach and Malabar spinach are heat-loving alternatives with very different growth habits.

New Zealand spinach

New Zealand spinach (Tetragonia tetragonoides) does well in sunny, hot, dry conditions. It prefers well-drained sandy soils, rich in organic matter, with a pH from 6.8 to 7.0. Seeds can be directly sown in the garden when all danger of frost has passed. Plant seeds 1/2 inch deep and 2 inches apart. Germination may take two to three weeks but is hastened by soaking the seeds for twenty-four hours before planting. This plant is much larger than traditional spinach, so rows should be 3 feet apart. Thin the plants to twelve inches apart when the seedlings reach 2 inches high. Each plant can grow up to 2 to 3 feet long and the planting area will eventually develop into a spreading mat of leaves. You can also start the seeds indoors three to four weeks before the last frost and transplant outside after the danger of frost.

Mulching is recommended as it will suppress weeds and retain moisture in the soil. Although New Zealand spinach is drought tolerant, its growth and flavor are dependent on an adequate supply of water. New Zealand spinach is also a heavy feeder. It is of interest to note that this plant does not bolt (flower and set seed) with drought, but rather from a lack of nitrogen. When it sets seed, the flavor of the leaves becomes more bitter. To avoid bitterness, start with a nutrient-rich soil and apply additional nitrogen fertilizer monthly throughout the growing season. One quarter cup of 20-0-0 fertilizer per 10-foot row is recommended.

Days to maturity is between fifty and seventy days. Harvest the smaller leaves and growth tips. New Zealand spinach will regrow well and continue until the first hard frost. Cutting the plant back to a node low on the stem will result in branching and regrowth.

Although the leaves feel more succulent-like than traditional cool-season spinach, it is a good substitute in the kitchen. Young leaves can be added to other salad greens. It can be chopped and steamed. New Zealand spinach is high in vitamins A, B1, B2, and C. It has, however, a high oxalate content in its leaves. Oxalates can be reduced by blanching for three minutes, draining, and then immersing in an iced water bath. New Zealand spinach freezes well and is a flavorful and healthy addition to soups and pasta dishes throughout the winter. To freeze, blanch, drain, and immerse in a bowl of iced water to cool, drain, and place in an airtight container. Double bagging in freezer-quality ziplock bags works well.

Malabar spinach

Malabar spinach (Basella alba), also known as Ceylon or Indian spinach, is a tropical vining plant that thrives in hot, humid conditions. There is also a red or burgundy-leaved variety (Basella rubra). Malabar spinach will require support. Trellising also provides for ease of accessing its leaves when harvesting. It is an attractive vine with glossy leaves that can be incorporated into your edible landscaping design.

Direct sow seeds two to three weeks after the last frost date in well-draining soil rich in organic matter and in full sun. It prefers soil with a pH between 6.5 and 6.8. Ideal soil temperature for germination is 65° to 75°F. This is about the time that spring-sown peas are done for the season and the perfect time to reuse that pea trellis. A minimum growing temperature 80°F, but it grows rapidly above 90°F. Seeds should be sown one-half-inch deep, one to two inches apart. Seeds may take up to a month to germinate but scarifying the seeds will hasten germination. Scarification is the process of modifying the outer hard coating of a seed so that water can penetrate. It is accomplished by rubbing with sandpaper, gently hitting with a hammer, or using a metal file to thin the coating. Seeds can also be started inside to be transplanted outside when conditions are favorable. When plants are 1 to 2 inches tall, thin to 6 inches apart. Malabar spinach will grow 3 to 6 feet tall and 2 to 3 feet wide.

Mulching is recommended for Malabar spinach as it suppresses weeds and also helps retain soil moisture. This is a tropical plant and needs adequate and consistent moisture. It will flower prematurely when stressed by drought. Flowering will reduce the quality of the leaves as they will become bitter.

Days to maturity is seventy to eighty days. Malabar spinach is extremely frost-sensitive. The growing season ends with the first frost.

Harvest young leaves often as they will have the best flavor. The leaves are mild and can be used, as traditional spinach is, in salads and cooking. Malabar spinach is nutritious: high in calcium and in vitamins A and C. Its leaves are slightly mucilaginous. Do not overcook it or it will become slimy. Store Malabar spinach in the refrigerator crisper as you would other salad greens.

Choose either New Zealand spinach or Malabar spinach (or both) and you will be rewarded with healthy greens in your garden and kitchen this summer.