Growing Spinach All Season Long

With early planting and adding a few varieties, we can get you growing spinach all season long!

A few tweaks and tricks can strengthen our spinach growing skills and save us from buying those – very expensive and oh so wasteful – plastic bags of half-wilted greens shipped across the country.

Not to mention the multiple recalls for listeria and E.coli outbreaks…

And, as we know that produce loses around 30% of its nutritional value within days of harvesting, growing our own makes sense both to our personal health and the health of the planet.

Plus, crunching sweet spinach leaves is one of the joys of an early season garden.

Growing Spinach

But if you’ve grown spinach, you may have also felt frustrated with plants bolting from an early season heatwave. By starting seeds earlier and exploring different strains and species of what people around the world use as ‘spinach’ we can enjoy these slightly finicky, nutrient packed greens in our gardens – and salads, all season long.

Bolting is when a plant changes its focus from growth to seed production. This will quickly make plants taste bitter, tough and in general inedible.

Start Your Spinach EARLY

Spinach is a cool weather crop, with optimum growing temperatures between 50⁰F – 60⁰F. So, starting plants extra early will ensure you’re harvesting baskets of spinach before the first heatwave hits. Or try planting in the fall to overwinter, Giant Winter Spinach grows well this way.

Spinach seeds germinate well in 40-55⁰F soil. I usually find these soil temperatures in my Zone 4b/5a covered gardens by mid-March. Seeds, planted ½” deep, take a week or two to germinate though, so remain patient. Once sprouted, seedlings are truly cold hardy, tolerating temperatures as low as 15⁰F.

Plant up to nine seedlings per square foot if intensively planting, or 6” for traditional spacing. Most plants get 6-10” high and almost as wide. Keep the soil consistently moist and switch to a shade cloth when temperatures warm over 80⁰F to prolong harvests.

Spinach prefers to do most of its growing in our (rapidly diminishing) shoulder seasons, but simultaneously likes a lot of sun, making spinach a great choice for winter sowing.

More on Winter Sowing Vegetables HERE

I also love starting seeds in late summer for a fall harvest, the trick is keeping the seedlings happy in the heat, adding a layer of grass clippings helps.

So Many Spinach Varieties!

Here’s a list of varieties I’ve grown and what I’ve thought of them.

Bloomsdale
Spinacia oleracea
40-50 days

This variety is a garden staple, and for good reason. It has loads of fresh flavor in its big, crinkly leaves. This open pollinated heirloom variety was bred from a single monoecious plant (most spinach is dioecious).  The “Longstanding” Bloomsdale variety holds off on bolting better than most and grows a little larger to 10” tall.

Space F1
Spinacia oleracea
25-50 days

This variety boasts more resistance to downy mildew. It also matures quickly, but holds off on bolting while staying sweet a little longer. Deep dark green, smoother leaves grow from an upright stem.

Caucasian Mountain Spinach
Hablitzia tamnoides
45-55 days

This perennial (to zone 3) variety produces tasty shoots in early spring. Often described as earthy flavored, the heart-shaped leaves follow typical patterns of being most tender when smaller, with more mature leaves doing best in pesto or cooked.

If given full sun, established plants will vine from six to nine feet long, making a green edible screen. The seeds should be cold-stratified. Note that growth is slow the first year, but vines after.

Lamb’s Quarter’s
Chenopodium album –  Wild Spinach, Goosefoot
50 days

This sun loving variety is cultivated in much of the world as an edible but seen as a weed in America. It is an aggressive plant, but a fun way to forage for your salad as you weed. Harvest long before the plant reaches its three foot height. It also contains more vitamins and minerals than any cultivated spinach.

Malabar Spinach
Basella rubra (red stems) alba (green stems) – Ceylon and Vine Spinach
70-80 days

Malabar makes a great warm-season alternative to spinach as it thrives in heat and humidity. The vines grow to eight feet, making for gorgeous edible trellises. The leaves, which taste like baby beet greens are edible both raw and cooked, though typically used as a stir fry or soup ingredient.

Start seeds inside four to six weeks before last frost, waiting to transplant until well after chance of frost.

New Zealand Spinach
Tetragonia tetragonioides
55-70 days

New Zealand spinach is a unique warm-season spinach alternative. While New Zealand spinach is drought tolerant, it tastes best harvested young after consistent watering. It really gets quite bitter after midsummer.

Harvesting the tips often encourages new growth. High oxalate content is reduced with cooking. Start seeds inside three to four weeks prior to the last frost. Soak seeds in water for 24 hours for better germination. Transplant seedlings well after chance of frost.

This funky native edible is usually the first harvestable green from my garden. The real bonus of growing these are the bright pink to red seed heads that give the plant its name. The ripe seeds are slightly sweet and juicy and really do look like berries. They’re a great addition to salads, and one of my favorite ‘in the garden’ snacks. As a native, beware it wants to self-seed.

All varieties can be harvested as a cut and come again green. Harvest often and in the morning. You can also blanche and freeze all varieties of spinach. I hope you’ll add a few more shades of spinach to your spring garden this year!

Stretching the Seasons

I love playing with growing under cover and Elliot Coleman introduced the concept of ‘Double Coverage’. On a much smaller scale than his market farm, I have been placing winter sowing jugs inside my cold frames and low tunnels – using ‘Double Coverage’ –  to get an even earlier start. Coleman estimates this practice moves your garden a thousand miles south.

Salty Spinach?

Have you noticed an almost gritty feeling on your homegrown spinach leaves? Congratulations, you’ve found where the plant has deposited extra mineral salts from the soil. Finding these salts on leaves is an indicator of mineral-rich soil – and freshly harvested greens!

So which new spinach varieties do you want to try?

*A version of this article first appeared in the Spring 2024 issue of Northern Gardener*

Dig In,
Michelle