Growing Spinach Successfully
By Susy Morris
One spring as I was showing a friend my vegetable garden, she said, “Your spinach looks wonderful. I can’t grow spinach. It bolts instantly. I gave up growing it long ago.” A month later, an online reader expressed the same sentiment, and asked me to share more on growing spinach. Spinach has the reputation of being a finicky crop, but it can be grown easily and successfully with attention to a few key details.
Perhaps our childhood memories of slimy canned spinach are what gives this veggie a bad rap and makes us reluctant to grow it in the garden. I’m guessing it has more to do with its tendency to bolt (send up a tall stalk to produce seeds) as soon as the temperatures warm up and the days get longer. I’ve had my share of experience with bolted spinach. Luckily, my chickens and pigs turn it into eggs and bacon. But since I enjoy fresh spinach in my bacon omelet, I learned how to grow it successfully in my own garden.
Spinach is cold-hardy, palatable, and a nutritional powerhouse, which makes it a valuable addition to the edible garden. It can survive temperatures as low as 19 degrees Fahrenheit, making it easy to grow during winter in Southern climates and possible to grow or overwinter in some Northern regions. For most gardeners, spinach can be seeded and harvested before lettuce, not to mention its leaves are sweeter and more tender when grown in colder weather. It can also continue growing longer into winter than lettuce can, allowing us to harvest food for our table over a longer time period.
The main thing to consider when growing spinach is its favored season. Spinach is a cool-weather crop. Thus, hot days and more hours of daylight increase the likelihood of bolting and bitterness, particularly if it was seeded or transplanted when the weather was still really cold. Spinach that’s planted very early in the season will bolt quicker than spinach that was planted later. Planting small amounts of seed every two weeks instead of all at once can increase overall yield. Overwintered spinach will bolt quickly in spring when the weather starts to warm up. While you can still grow it in hot weather, it’s much easier during the cool season. Plant in fall, winter and spring depending on your climate, and leave the hot summer season for the crops that love the heat.
Sun, soil and seeds
Spinach does not need full sun, and in fact, planting it in a shady corner of the garden will help keep it from bolting as quickly. Of course, it can take full sun if that’s all you have, and it does appreciate more sunlight in the spring and fall, but it isn’t necessary for growth. If your garden is shady, spinach will do just fine.
Since spinach produces a long taproot, it will appreciate deep, rich soil. It’s much more tolerant of dense soil than other greens, and in fact, it prefers soil that retains moisture. Clay soil will actually help keep spinach from bolting as quickly in hot weather. In dry or “lean” soil, mulching plants with compost will not only feed the plants, but it will keep soil cool and maintain moisture levels. Water spinach regularly, as the stress of dry soil encourages it to flower and set seed. Keep the soil moist, but not waterlogged.
Spinach grows well by either direct seeding or small transplants, but many gardeners get better germination rates with transplants. Sow spinach seeds in flats at a rate of four seeds per cell or soil block. Thin out to one plant per cell when seedlings have four true leaves. Transplant 6 inches apart in rows 12 inches apart. This may seem like more work than direct seeding, but spinach is sensitive to overcrowding. Allowing for more space reduces the risk of premature bolting.
Spinach is also sensitive to root disruption. If sowing directly into the garden, thin seedlings carefully so as to not disturb the soil more than necessary. If transplanting, water seedlings well before and after.
Starting spinach indoors also helps control issues with slugs, cutworms and wireworms, which can be problematic with direct sown spinach in spring. Working with transplants will help you get a jump on the season, and you can transplant young plants around the same time you would direct sow seeds.
For direct seeding spring spinach, seed four to six weeks before last frost. For fall and winter sowings, seed six to 10 weeks before first frost. Keep in mind that warm soil temperatures inhibit germination in fall plantings. Seed thickly and keep well-watered to encourage better germination.
For indoor seed starting, seed spring flats two to three weeks ahead of dates for direct seeding so plants are sized to transplant at direct sowing time. Seed fall flats six to 10 weeks before first frost. Place fall planted flats in a cool basement until seeds germinate. This will increase germination rates.
Mulch heavily to reduce weeds, and if a few weeds do pop up, pull them while they’re still small to reduce the risk of disturbing the spinach roots.
It is important to not overfeed spinach. Overloading with fertilizer will encourage premature bolting and increase the likelihood of pests like aphids. A little compost or light fertilizer mixed into the soil at planting time, and watering once during the growing season with a liquid kelp solution, is all spinach will need to thrive.
For the best of both worlds – young, tender leaves for salads and mature leaves for cooking – plant 4 to 6 inches apart, and harvest every other plant for baby leaves while leaving the remaining plants to mature to full size.
To keep spinach producing, cut outer leaves as needed, and allow the small inner leaves to continue growing. This will extend harvest and increase total yield from each plant, especially with fall plantings.
As soon as you see the telltale signs of bolting – lots of triangular leaves in the crown of the plant – cut the entire plant. You can still use the leaves when the spinach starts to bolt, but bitterness might be an issue. The hotter the weather, the more likely the leaves will be bitter.
Spinach comes in many varieties, shapes and textures. There are smooth-leaved and savoyed (crinkly) varieties. My personal preference is the texture of the savoyed leaves. There are varieties with colored veins, similar to chard. If you find one variety unappealing, try other varieties. We live in an era of choice, especially when it comes to varieties of vegetables to grow in our gardens, so take full advantage of the options available to you.
While heirlooms are appealing, newer hybrids will most likely increase your chances of success when growing spinach, especially when it comes to warmer weather or overwintering. Try a few different varieties, including heirlooms, and find which works best for your soil. You might find that one variety grows better in your microclimate than another. In my garden, the heirloom Bloomsdale Long Standing and the hybrid Catalina both do very well. Tyee produces a good fall crop, and Space from Johnny’s Selected Seeds is great for early and late plantings.
Spinach seed does not store well, so it is extremely important to start each season with fresh seed for proper germination. Old seed will be slower to germinate and have lower germination rates.
If you have dry, lean soil or live in an extremely hot area, don’t give up growing spinach altogether. Contact a seed source that specializes in farm seed like High Mowing, Johnny’s Selected Seeds, or a similar source in your region. They should be able to recommend a variety that’s more likely to succeed in your climate. Ask around at the local farmers’ markets when you see a stand with nice spinach. Farmers are often more than happy to tell you which varieties they grow.
Even with taking steps to reduce the risk of bolting, spinach will still bolt eventually. Plants want to set seed to ensure survival. In order to have spinach over a long season, continue to plant fresh seed in the garden or in flats every 10 to 14 days. If your spinach does happen to bolt, all is not lost. You can still eat the leaves – raw in salads or cooked. If you have a flush of it, cook, puree and freeze in ice cube trays to add extra nutrition to soups, stews
By following these tips, you can grow plenty of nutritious spinach all season long. As gardeners, eating spinach like Popeye should be a priority – think of how much you could accomplish in the garden with those beefy arms.
Susy Morris is a Maine-based blogger, photographer, and hobby farmer who loves to try new things and experiment with different techniques to make her farm and garden more sustainable.
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