Had little luck with spring-sown spinach? Bust the slump by planting this brilliantly green, nutrition-packed vegetable at summer’s end.
Photo by David Cavagnaro
Spinach ranks as one of the most delicious and tender of all the leafy greens, yet this delightful crop is conspicuously absent from many gardens. The reason? Frustration likely settled in for growers who had planted spinach in spring and reaped only a small harvest of undersized, parched leaves before the spindly central flower stalk appeared, signaling the plant was starting to bolt or run to seed.
What’s the best remedy for the spring spinach blues? Plant a fall crop! By planting spinach at the end of summer, your crop will get off to a running start and mature to its luscious best during the cool, golden days of fall.
To appreciate why spring-sown spinach misbehaves, one must be familiar with the plant’s humble origins. Spinach is a cool-season vegetable originally grown in fall and winter in the fertile agricultural valleys of the Middle East. In spring, longer days and higher temperatures prompt spinach to finish its cycle and go to seed.
While many modern spinach growers deem early hot weather the villain behind spinach’s bolting, the true culprit is actually the increasingly long days of spring, which signal to the plant that it’s time to reproduce. Most present-day spinach varieties will initiate flowering when the daylight duration reaches 14 hours — as early as mid-May in the northern half of the United States.
The influence of hot weather, while more subtle, also has an adverse effect on the quality of spring-sown spinach. Even mildly hot days in the upper 70s can dramatically speed up the flowering of a spinach plant that has already been triggered to bolt by day length. Additionally, the tenderness and juiciness of spinach leaves diminish greatly after just a couple of days of hot spring weather.
Some gardeners can certainly boast success stories of spring-planted spinach, but any grower will be challenged by the one-two punch of longer daylight hours and early hot weather. Timing a fall crop properly can help you avoid the pitfalls of a spring one, resulting in a bumper harvest of huge, succulent, easy-to-pick spinach leaves.
Your Fall Spinach Target Planting Date
Seed catalogs and gardening guides often advise planting fall spinach crops four to six weeks before a hard frost. In my own experience in both coastal Washington state and southern Wisconsin, that means planting between Sept. 1 and 10. Unfortunately, this strategy delivers plants that are only about the diameter of a teacup and develop leaves the size of silver dollars before the days become too cool for continued growth. This teacup size is perfect for overwintering spinach (see “Overwintering Spinach” later in this article), but it doesn’t produce the yield a fall crop should.
Taking a tip from commercial spinach farmers who plant their fall crop eight to 10 weeks before the first hard frost, I tried planting a number of spinach varieties between the first and third weeks of August. That method has worked so well that I’ve been spreading the news to my spinach-growing friends in other parts of North America, and all of us have been amazed at our success.
Prolific Fall Varieties
I’ve grown a wide range of spinach varieties — open-pollinated and hybrid, smooth-leaf and savoy (wrinkled or curly) — in my fall gardens. The first thing I discovered was that varieties I knew well from spring planting performed differently in fall. For example, in spring, ‘Olympia’ grows more quickly than the bolt-resistant standard, ‘Tyee,’ but in hot August weather, ‘Tyee’ out-yields ‘Olympia.’ I’ve had similar success with the semi-savoy variety ‘Indian Summer,’ which, like ‘Tyee,’ quickly produces baby-leaf cuttings by the end of August and nice, full-grown leaves by mid-September.
Other varieties that do well from early-August plantings (Aug. 1 through 10) are the smooth-leaf varieties ‘Olympia,’ ‘Space’ and ‘Viroflay.’ While these are not as fast-growing in August as ‘Tyee,’ they seem to come into their own with the cooler weather of September, sometimes producing leaves that are 5 to 6 inches in diameter. In several regions, ‘Olympia’ performs superbly from August plantings, offering the largest yields of all the varieties tested. ‘Olympia’ and ‘Viroflay’ have also proved to be especially tasty varieties if harvested in late September and October. ‘Winter Bloomsdale’ doesn’t grow quickly but keeps turning out succulent savoy leaves into the cold days of October.
David Cavagnaro, a veteran vegetable gardener and photographer, has tried his hand at planting spinach in August in his gardens in Decorah, Iowa. Cavagnaro is enthusiastic about the tremendous yields he gets in late September from his early-August plantings. He says fall spinach is by far the best spinach he’s ever grown. “Even the big leaves are still succulent and juicy,” he says. Smooth-leaf ‘Olympia’ and ‘Space’ varieties are also the top yielders in my own garden in Bellingham, Wash. In late September, both grow to sizes most gardeners only dream about.
C.R. Lawn of Fedco Seeds in Waterville, Maine, had a similar experience, with ‘Olympia’ outperforming all other varieties in his fall garden. Lawn praises the whole concept of fall spinach. “There’s nothing like the spinach you harvest on those crisp fall days,” he says. “By the time it’s ready, the weather is cool and there’s plenty of moisture — that’s what spinach really likes.”
Steve Bellavia, a vegetable researcher at Johnny’s Selected Seeds in Winslow, Maine, also grew August-planted fall spinach a couple of years ago. While many of the varieties he planted were impressive for their tenderness and yield, Bellavia says he was most struck by the performance of ‘Spinner,’ which he says grew to a nice, full size, was dark green and flavorful, and was the best variety in the trial.
Many people think savoy spinach varieties taste better than smooth-leaf types, but that assessment doesn’t necessarily seem to hold true in the case of fall crops. In our trials, the smooth-leaf varieties ‘Olympia’ and ‘Viroflay’ both received rave reviews for flavor, while the standard savoy variety, ‘Bloomsdale Long Standing,’ and its modern semi-savoy cousin, ‘Tyee,’ both proved to be less flavorful.
Seeds: Keep Your Cool
Bellavia also reminded me of one of the drawbacks of planting fall spinach. When he planted a fall spinach plot in early August, the soil was somewhat dry and then received just one-third inch of rain, after which daytime temperatures hovered in the low 80s for a couple of weeks. Although the soil never became excessively dry, the spinach came up rather sparsely.
Of course, this can happen with any crop if you allow the seed bed to dry out after planting, but this is especially problematic for spinach when the weather is hot. Spinach seed doesn’t germinate well at temperatures above 75 degrees Fahrenheit, and it won’t come up at all if soil temperatures are above 85 degrees. One way to get a good stand of spinach when planting in late summer is to water it lightly on hot days. This will cool the soil enough to get your crop established.
We also found that not all spinach varieties planted in early August fared as well as some of our big winners, such as ‘Olympia’ and ‘Spinner.’ Cavagnaro and I have had early-August plantings of savoy varieties ‘Bloomsdale Long Standing’ and ‘Coho’ bolt by early September. Why? Presumably because, in our locations, the day length was long enough in mid-August to trigger flowering.
By trying a number of different planting dates throughout August, we’ve found that planting between Aug. 15 and 20 seems to be the best time for northern gardeners. You’ll bypass the hottest days of early August, which can be tough on spinach germination, and you’ll avoid possible bolting problems if you’re in the higher latitudes of the North. We’ve found that all of the best fall varieties did well when planted in mid-August.
Planting Spinach in the South
Growing fall spinach has a long legacy in parts of the southern United States. A large amount of fresh-market spinach was at one time grown for fall consumption in coastal Virginia and Maryland, near the Chesapeake Bay. These crops were traditionally planted for the fall crop from mid-August until mid-September. Long, warm autumns in this and other mid-Atlantic areas ensure bountiful crops that may yield until the new year.
In Arkansas and Oklahoma, spinach can be planted in the second half of September for fall salads that easily last into December. In southern Texas and in much of the Deep South, spinach can be planted anytime from early October until the middle of November for a fall crop that will grow through winter. In the desert Southwest, where there’s a wide range of environments based on elevation, planting from late August until late November is possible, but you’ll have to experiment to determine precisely what’s best for your location.
When you plant spinach in these hotter regions, it’s much like planting it in August in the North: Keep the seed bed cool with some irrigation water (or some shade) until the seedlings have emerged.
Spinach is one of the hardiest winter vegetables, sometimes surviving temperatures far below freezing if grown to just the right size before the most frigid part of winter. ‘Giant Winter’ and ‘Winter Bloomsdale’ are the standards for overwintering, and ‘Melody’ and ‘Tyee’ have been successfully overwintered in upstate New York and New England. Savoy varieties generally endure cold better than smooth-leaf types.
The general rule for getting the right-sized spinach for overwintering is to plant it four to six weeks before your average first hard frost date. This should produce a spinach plant about 3 1⁄2 to 4 inches in diameter — the best size for overwintering. As far as mulching the plants for protection, in my own experience in wet Maine and Washington winters, I’ve killed the plants, as they ended up rotting under my leaf mulch by the time I uncovered them in early spring. Perhaps porous row covers would work better.
Wilted Spinach Salad Recipe
Succulent fall-grown spinach is great for this recipe. Just tear the bigger leaves into bite-sized pieces after washing.
Wash, trim and dry 6 cups of spinach and place into a large salad bowl. Sauté 4 or 5 slices of bacon until crisp, remove from pan, and cut into bits. Drain off all but 2 tablespoons of fat and add 1 tablespoon of olive oil. (For a vegan or vegetarian alternative, skip the bacon altogether and start with 3 tablespoons of olive oil.)
Sauté 1 cup grated onion in fat or oil for just a minute before adding 1/2 teaspoon salt, 1 teaspoon sugar, 1 tablespoon balsamic vinegar and 3 tablespoons white vinegar. When sugar and salt are dissolved, slowly pour the hot liquid over the spinach and liberally grind black pepper over the salad. Toss. Garnish with chopped bacon and serve on warm plates.
Spinach Seed Sources
Territorial Seed Co.
Johnny’s Selected Seeds
J.W. Jung Seed Co.
Baker Creek Heirloom Seeds
William Dam Seeds
‘Giant Winter,’* ‘Space’