Plant nutritious spinach in the fall for the best harvest.
Spinach is one of the most tender and delicious of all the leafy green vegetables. Yet in many gardens this delightful crop is absent. The reason? Many gardeners have been frustrated because they plant spinach in spring and get only a small harvest of undersized, parched leaves before the spindly central flower stalk appears, signaling the plant is starting to bolt or run to seed.
What's the best remedy for the spring spinach blues? Plant a crop of nutritious spinach in the fall! By planting spinach at the end of summer, you'll get your crop off to a running start and have it mature to its luscious best during the cool, golden days of fall. After several years of trialing spinach varieties and gathering information from other spinach aficionados around the country, I'm convinced spinach can have a jump in popularity if we just keep it cool.
To appreciate why spring-planted spinach misbehaves, one must know its 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 warmer temperatures trigger spinach to finish its cycle and go to seed.
While many modern spinach growers blame early hot weather as the villain causing spinach to bolt, in actuality it is the increasingly long days of spring, which signal the plant to reproduce. Most modern spinach varieties will initiate flowering when the days reach 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 spinach sown in spring. Even mildly hot days in the upper 70s can dramatically speed up the flowering of a spinach plant that's already been triggered to bolt by day length. Also, the tenderness and juiciness of the leaves is greatly diminished after just a couple of days of hot spring weather.
Certainly some gardeners claim success stories of spring-planted spinach, but any gardener will be challenged by the one-two punch of longer daylight hours and early hot weather. Timing a fall crop properly can help you easily avoid the pitfalls of spring, resulting in a bumper harvest of succulent, huge, easy-to-pick spinach leaves. Just look at the size of those leaves in the picture above!
Your Fall Spinach Planting Target Date
Seed catalogs and gardening guides often advise gardeners to plant their fall spinach crops four to six weeks before a hard frost. In my own experience in both coastal Washington state and southern Wisconsin, this means planting between September 1 and 10. Unfortunately this strategy produces plants that are only about the diameter of a teacup with 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 a full eight to 10 weeks before the first hard frosts, I tried planting a number of spinach varieties between the first and the third weeks of August. This method has worked so well I have been spreading the news to my spinach-growing friends in other parts of North America, and all of us have been amazed at our shared success. We've been comparing notes on what varieties work the best, and here's what we've found.
Bountiful Fall Spinach Varieties
I've grown a wide range of spinach varieties, both open-pollinated and hybrid, smooth-leaf and savoy (wrinkled or curly), in my fall gardens. The first thing I learned was that varieties I knew well from spring planting performed differently in fall. For example, in spring "Olympia" grows faster than the classic bolt-resistant standard "Tyee," but in hot August weather, "Tyee" out-yielded "Olympia." I've had similar success with the semi-savoy-leaf variety "Indian Summer," which, like "Tyee," quickly produced baby-leaf cuttings by the end of August and nice full-grown leaves by mid-September.
Other varieties that did well from early August plantings (August 1 through 10) were the smooth-leaf varieties "Viroflay," "Space" and "Olympia." While these are not as fast-growing as "Tyee" in August, they seem to really come into their own with the cooler weather of September, sometimes producing leaves that are 5 to 6 inches in diameter by late September. In several regions, "Olympia" performed superbly from August plantings, producing the largest yields of all the varieties tested. "Viroflay" and "Olympia" also proved to be especially tasty varieties when harvested in late September and October.
"Winter Bloomsdale" didn't grow fast, but chugged along and kept producing succulent savoy leaves into the cold days of October. David Cavagnaro, a skilled vegetable gardener and photographer, has also tried his hand at planting spinach in August in his gardens in Decorah, Iowa. David is very enthusiastic about the tremendous yields he gets in late September from his early August plantings. He says it is by far the best spinach he's ever grown. Some leaves are the size of his outstretched hand. Even the big leaves are still succulent and juicy and are really fun to pick, he says. Smooth-leaf "Olympia" and "Space" varieties were also the best yielders in my own garden in Bellingham, Washington. In late September both grew to sizes most gardeners only dream about.
Out on the East Coast, C.R. Lawn of FEDCO Seeds in Waterville, Maine, had a similar experience, with "Olympia" outperforming all others in his fall garden. C.R. praises the whole idea of fall spinach. There's nothing like the spinach you harvest on those crisp fall days. By the time it's ready, the weather is cool and there's plenty of moisture that's what spinach really likes.
Steve Bellavia, trials manager at Johnny's Selected Seeds in Albion, Maine, also grew fall spinach a couple of years ago, planted in August. While many of the varieties he planted were impressive for their tenderness and yield, Steve was most struck by the performance of "Spinner." [It] grew to a nice full size, was dark green and flavorful, and was the best variety in the whole trial, he says.
Many people believe savoy spinach varieties taste better than smooth-leaf types, but that doesn't seem to be true with fall crops. In our trials, the smooth-leaf varieties "Olympia" and "Viroflay" both got rave reviews for flavor, while the standard savoy variety, "Bloomsdale Long Standing," and its modern semi-savoy cousin, "Tyee," both proved less flavorful.
Keep Your Spinach Seeds Cool
Bellavia also reminded me of one of the pitfalls of planting fall spinach. When he planted a fall-spinach plot in early August, the soil was somewhat dry and then received 1/3 inch of rain; 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 when 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 above 75 degrees and won't come up at all when 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 sod enough to get a good stand established.
If you use this trick, try to plant into raised beds in the best-drained spot in your garden to reduce the risk of root rot. A well-drained soil also will stay warm longer, enabling the spinach to grow a little more before the season comes to an end. A soil with lots of mature compost worked into it is very desirable, as spinach is a very heavy feeder. We also found not all spinach varieties planted in early August fared as well as some of our big winners like "Olympia" and "Spinner." David and I have had the early August plantings of savoy varieties "Long Standing Bloomsdale" and "Coho" bolt by early September. Why? Presumably because in our locations the day length was still long enough in mid-August to trigger flowering. By trying a number of different planting dates throughout August we've found planting between August 15 and 20 seems to be the best time of all for Northern gardeners. You'll avoid 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. Certainly we've found that all the best fall varieties did well planted in mid-August.
Planting Spinach In the South
In parts of the southern United States, growing fall spinach has a long legacy. A large amount of fresh market spinach was once 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 will 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 can take you 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 grows through the winter.
In the desert Southwest, where there's a wide range of environments based on elevation, it's possible to plant from late August until late November, but you'll have to experiment 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 emerge. Formerly a spinach breeder at Alf Christianson Seed Company in Mt. Vernon, Washington, John Navazio now breeds spinach and other crops specifically for organic growers in the Upper Midwest.
Spinach is one of the hardiest winter vegetables, sometimes surviving temperatures far below freezing if grown to just the right size before going through the coldest part of winter. "Winter Bloomsdale" and "Winter Giant" are the standards for overwintering, and "Tyee" and "Melody" have been successfully overwintered in upstate New York and New England. Savoy varieties generally overwinter better than smooth-leaf types.
The rule of thumb for getting the right-size 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 to 4 inches in diameter, the best size for overwintering. As far as mulching the plants for protection, all I can say is that in my own experience in wet Maine and Washington winters, I've killed the plants, as they had rotted 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-size pieces after washing.
Wash, trim and dry 6 cups of spinach and place into a large salad bowl. Saute 4 or 5 slices of bacon until crisp, remove from pan and cut into bits. Drain off all but 2 tablespoons fat and add I tablespoon olive oil. (For a vegan or vegetarian alternative skip the bacon altogether and start with 3 tablespoons of olive oil.)
Saute cup grated onion in fat or oil for just a minute before adding 1/2 teaspoon salt, 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
Johnny's Selected Seeds
"Indian Summer," "Space," "Spinner," "Tyee"
Seeds of Change (all organic seed)
Santa Fe, NM
William Dam Seeds
Dundas, ON L9H 6M1 Canada
"Space," "Giant Winter" *
Abundant Life Seed Foundation
Port Townsend, WA
"Winter Bloomsdale," "Giant Winter" *
J.W. Jung Seed Company
* = Open-pollinated