Spinach is a cool-season plant that’s one of the first crops of spring and a great fall crop as well. You’ll enjoy growing this undemanding plant and will enjoy eating it even more. Harvest spinach any time to enjoy raw in salads or cook it up in seconds for a delicious side dish that’s loaded with vitamins and minerals. If you want to grow spinach in your garden, here’s everything you need to know.
You can also download my How Do I Grow Spinach? one-sheet and keep the free resource handy for your reference.
When, Where and How to Plant Spinach
Spinach can be either sown directly into the garden or started from seeds indoors. For the least work and the most convenience, seedlings can also be purchased from a nursery in spring.
To give spinach a head start, plant seeds in sterile seed-starting mix indoors about six weeks before the last expected frost date. The seeds will germinate one to two weeks later in soil that is between 60 and 68 degrees. If growing in a room that stays cool, consider using a seed-starting mat that will raise the temperature of the soil.
Spinach is frost tolerant, so it can go in the ground long before many other crops. When spinach seedlings have two true leaves and when there are four or fewer weeks remaining until your last frost date, the seedlings may be transplanted outdoors.
Seeds can be planted outdoors as soon as the soil is workable in spring — about six weeks before the last expected frost — and they will germinate as the days warm.
To germinate seeds faster and more reliably, there is a process called “priming.” A week before sowing spinach seeds indoors or out, soak seeds in room temperature water overnight or up to 24 hours. Next, place the seeds on a paper towel to air dry for one or two days. Once the seeds appear dry, place them in an airtight container and store the container in a cool place. The seeds will have soaked up and retained enough water to stimulate the first stages of germination. Wait at least five days, but no more than seven, and sow the seeds.
Primed spinach seeds will germinate both faster and more uniformly: In about five days, the grass-like seedlings will emerge.
Spinach seeds last up to three years in storage. If in doubt about the age or viability of spinach seeds, prime and sow a few seeds early to test the batch. If the test seeds don’t germinate, it’s time for a new packet.
For a steady harvest over several weeks, a good strategy is to plant a new crop every 10 days. Each crop can be sown directly, or you can stagger plantings of both seeds and seedlings. Continue these succession plantings until it’s time for summer crops to go in. When late summer comes, start up again for fall crops.
Spinach grows well in a wide variety of soils, but like most crops, it does best when the soil is well amended with lots of organic matter, especially compost. The ideal pH range for spinach, like many common vegetable crops, is 6.5 to 7.0. A soil test can tell you if you are near the target and, if not, what amendments can be added to the soil.
Spinach will grow best in full sun — six to eight hours of direct sunlight — or partial shade.
Follow the spacing instructions that come on the seed packets for the variety you have, or plant just a little denser with a plan to later eat the baby spinach that you will remove while thinning the crop.
Types & Varieties of Spinach
There are two main types of spinach: Savoy and smooth-leafed.
Savoy spinach and semi-savoyed spinach have dark green leaves characterized by their wavy or puckered leaves, and they include some of the best varieties for growing in cold weather. And yet, some savoy spinach varieties are adapted to withstand heat, offering the best of both worlds.
Smooth-leafed spinach, also called flat-leaf spinach, is the kind you often see in salads. It can be harvested as baby greens for sweeter, more tender leaves, or allowed to grow.
Auroch is a fast-growing smooth-leafed spinach that performs best in fall, winter and early spring, with a high resistance to downy mildew. It’s ready for harvest in 24 days.
Bloomsdale is a classic variety of savoy spinach that withstands heat better than others, so it offers the best of both worlds, and it’s renowned for its garden-fresh flavor. In 50 days, it produces thick, succulent, dark-green leaves that are very sweet in salads. When planted in autumn, Bloomsdale will overwinter and mature in the early spring, though it’s best sown in early spring for late spring and early summer harvests.
Gazelle is a smooth-leafed spinach with uniform leaves and bunches that make it perfect for baby leaf harvest. It’s also highly downy mildew resistant and ready for harvest in just 26 days.
Palco matures in 38 days and is adaptable as both a cool-season or warm-season crop. It is a flat-leaf spinach that may be harvested as baby greens or enjoyed after attaining its full size. It is both bolt and mildew resistant.
Red Tabby is a red-veined smooth-leafed spinach with angular leaves in an upright growing habit. It matures in a month and is downy mildew resistant.
Renegade has fleshy, round, smooth, dark green leaves and sweet, tender stems. It’s a flat-leaf spinach that matures in 42 days.
Space is a slightly savoyed spinach with medium green leaves that are highly resistant to downy mildew and mature in just 25 days. It is versatile — grow it in all seasons.
Spinach is a thirsty crop that enjoys up to 1.5 inches of water a week. If it hasn’t rained that much in a week, make up the difference with supplemental irrigation. Water under the foliage, right at ground level, to avoid wetting the leaves, which invites plant diseases. When growing spinach, it’s really nice to have a drip irrigation system for a slow and consistent application of water — but it’s not necessary as long as you keep on top of watering the garden when Mother Nature fails to.
A 2-inch layer of organic mulch such as shredded leaves, pine bark or straw will help keep the soil cool and moist between waterings.
As long as you have good rich soil, spinach isn’t a demanding plant. But it can help to add some organic nitrogen-based fertilizer — like alfalfa, soybean meal or blood meal — at planting time. Adding compost before planting will also help the plants along, and balancing the pH will ensure the nutrients in the soil are readily available to the plants.
Spinach Pests & Diseases
When it comes to pests and diseases, spinach is a gardener’s dream since it rarely succumbs to any serious problems.
Provide adequate spacing to allow for good air circulation to avoid mildew. If downy mildew does become a problem, practice crop rotation or choose resistant varieties.
Proactively check for slugs, which are easily controlled with a number of environmentally-friendly options, including handpicking, placing bowls of beer near the plants at soil level, or using a pet-safe iron phosphate bait like Sluggo.
And of course, the best part of spinach is eating it. You can harvest spinach whenever you want. This is one of those cut-and-come-again plants that I love so much since new leaves will resprout to replace the ones you cut. Simply snip away individual leaves as soon as they’re big enough to use. Or you can cut the entire plant about an inch above the soil level. Cutting encourages new growth and another crop of leaves and that makes me a very happy and healthy gardener!
When spinach bolts — that means it has sent up a flower stalk and “gone to seed” — it becomes bitter. This happens when the weather heats up in summer. At this point, the plant is done. Pull it out and add it to the compost pile, and plant your next crop in its place.
What are your secrets to growing spinach successfully? Let us know in the comments below.
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Links & Resources
Some product links in this guide are affiliate links. See full disclosure below.
joegardener Online Gardening Academy™: Three popular courses on gardening fundamentals; managing pests, diseases & weeds; and seed starting.
joegardener Online Gardening Academy Beginning Gardener Fundamentals: Essential principles to know to create a thriving garden.
joegardener Online Gardening Academy Growing Epic Tomatoes: Tomato expert Craig LeHoullier joins me in leading this course on how to grow healthier, productive tomato plants and how to overcome tomato-growing challenges. You can sign up to be notified when enrollment opens.
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