Margaret Lauterbach

Margaret Lauterbach: Like spinach? If you’re in the Treasure Valley, plant now.

Trails left by leaf miner maggots inside spinach leaves. Planting strategies can help you minimize, if not avoid, this.
Trails left by leaf miner maggots inside spinach leaves. Planting strategies can help you minimize, if not avoid, this.

Did you know some spinach plants are male and some are female? Some male plants remain shorter than others of that species, and all male plants go to flower before females, emitting small clouds of pollen.

I think gender identity of spinach is really only important for seed savers, and gender differences mainly show up when flowering and setting seed, not obviously on foliage. If males are in short supply, some females may develop male blossoms and pollen to complete their cycle.

Spinach is definitely a cool weather crop. Some of my favorite varieties bolt to flower then seeds when weather begins topping 70 degrees or day length exceeds 14 hours. Spinach is very light sensitive, so some say you should not plant it where it will receive light from street lights, for example. Other than that, it does need full sun exposure and fairly abundant water, but doesn’t like standing water.

Spinach is loaded with nutrition, although not as heavy in iron as the old Popeye tales indicated. It’s a good source of vitamins K, A, B2, B6, E and C, plus manganese, folate, protein and several minerals. It also packs a punch of fiber.

Plant now

I think here in the Treasure Valley it’s time to plant this wonderful vegetable if you didn’t sow its seeds last fall. You could “winter sow” seeds in transparent jugs, or mix seeds with planting mix and refrigerate for a week to speed germination. Sprouting usually takes six to 14 days in soil at least 35 degrees F. temperature. If your soil is wet, don’t walk on it, lest you compact the soil. You can usually lay boards down to spread your weight and walk on those, without compacting. This is another case of raised beds advantage, for you can walk on established paths between beds.

If you planted spinach seed in fall, it should be coming up now, or beginning to grow. In about one week our daylight hours will surpass 10 hours per day assisting green growth.

Do not plant spinach where you had planted spinach, beets or Swiss chard last year, for our worst pest on spinach is the leaf miner. Eggs are laid by a tiny fly, usually on the backs of leaves in tiny strips next to one another so they appear as a white blob unless you look closely. When these eggs hatch, the maggots burrow into the leaves, between the top and bottom cells of the leaf. As they feed their route looks like a wandering tan trail on the leaf. Sprays will not reach those maggots. In our valley there are two or three generations per growing season, at least, before the fly parent drops to the soil to pupate. They are flies, and can find where you planted spinach the next year, but why make it easy for them?

Leaf miner flies are attracted to sticky blue cards (and so are thrips), so you can control at least some of them by posting cards near crops that attract them. Cards are available at garden supply stores.


Spinach seeds are of two types: prickly and round. Prickly spinach seeds produce smoother leaves than round seeds. Leaves of round-seeded spinach usually are heavily savoyed (crinkled). Some regard this crinkling as harder to clean, but tepid water and sloshing around, changes of water, etc., will remove grit and tiny insects other than leaf miners. You can tear off those “mined” leaf sections if enough of the leaf is intact. For washing leaves, I prefer to use a light-colored enameled tub so I can see when the bottom is clear of grit after changes of water.

Bottom leaves of spinach are largest, and may be pulled off, leaving the interior to continue growing and producing new leaves. I love spinach raw in salads, but it’s better for you when it’s cooked. The only cooked spinach I like is cooked with sweet and sour sauce (my grandmother’s Pennsylvania Dutch sauce). Spinach contains oxalic acid that interferes with calcium intake when eaten fresh, but cooking dilutes that acid, so one can take advantage of the calcium in the vegetable.

Spinach botanically is known as Spinacea oleracea. Hot weather substitutes include perpetual spinach, also known as spinach beet, botanically identified as a different genus, Beta vulgaris var. cicla. Orach, also called “mountain spinach,” is Atriplex hortensis. New Zealand spinach isn’t spinach either, it’s Tetragonia expansa, and another hot weather spinach substitute, Malabar spinach, is Basella alba.

Spinach was native to Persia (Iran), introduced to India then China (via Nepal) in the 7th Century AD, and to Sicily in the 9th century by Muslims. It was later imported to America from Europe. Breeders have worked to tweak the crop into darker and larger green leaves, earlier growth habit and delayed bolting. Spinach is fairly greedy for nitrogen and potassium, but beware of too much nitrogen. Concentration of nitrates in leaves can reach toxic levels, especially after using ammonia fertilizers. Better to use fish fertilizers and/or kelp.

Send garden questions to or Gardening, The Statesman, P.O. Box 40, Boise, ID 83707.