How to Plant, Grow, and Care For Spinach in Your Garden
Are you thinking of adding some spinach to your home garden? Spinach can be one of the best plants to start with in a garden, especially for beginning gardeners, or even kids. But how do you get the most out of your spinach harvest? In this article, organic gardening expert Logan Hailey examines how you can get the most out of your harvest with this comprehensive guide on planting, growing, and caring for spinach in your home garden.
Whether you enjoy it in green smoothies, pasta, veggie bowls, or delicious autumn salads, spinach is a cool-weather garden staple. It’s is easy to grow fresh green and provides an ongoing harvest. Often it is the first green in the spring and last in the fall. You can even grow it all winter long in some areas (USDA growing zone 6 or warmer).
Spinach is a low-maintenance crop with very few pests or disease issues. Its quick-growing, easy-going culture is perfect for advanced and novice gardeners alike. It’s also packed with nutrients, making it an easy choice for health-conscious gardeners that plan to incorporate it as a food source in their diet.
After seven years of growing organic spinach on a commercial scale, I’ve discovered a few tricks to making this delicious green thrive in almost any garden. Let’s jump in and take a look at how to plant, grow, and care for spinach!
Plant Type Annual
Plant Family Amaranthaceae, Chenopodiaceae
Plant Species Spinacia oleracea
Plant Genus Spinacia
Hardiness Zone USDA 3-9
Season Spring and Fall
Sun Exposure Full Sun to Partial Shade
Watering Requirements Moderate
Maturity Date 24-30 Days
Companion Plants Brassicas, Cool Weather Greens
Don’t Plant With Fennel, Potatoes
Soil Type Alkaline, Loamy
Plant Spacing 1-2” for Baby Leaf, 4-6” for Full Size
Fertility Needs Light to Moderate
Plant Height 4-6 Inches
Diseases Downy Mildew
Pests Few to None
All About Spinach
Spinach is a leafy iron-rich green popular in many cuisines. It is an annual low-growing crop and member of the Amaranthaceae/Chenopodiaceae family, along with beets, chard, amaranth, quinoa, and lambs quarter. Some varieties are perennial veggies, which means they will regrow each year.
It prefers more alkaline soils (sandy soils with pH 7 or greater). It is best grown in the cool weather of spring and autumn. Long days and summer heat over 75-80 degrees Fahrenheit will cause it to bolt (go to seed) very quickly. Seeds will not germinate well in temperatures over 75 degrees.
Propagation and Planting
You can grow spinach from direct seeding or transplant it into the garden after sowing indoors. It grows very quickly and prolifically so long as you provide the right growing conditions.
Succession planting means growing several rounds of spinach throughout the season. At a given point in my fall garden, I may have spinach that is just germinating, baby spinach that is almost ready to harvest, and full-size spinach that I am picking off of. This ensures you have a continuous supply of nutritious greens.
When you decide on your planting dates in the garden, consider staggering them so you get a few successions throughout the season. It takes 24-30 days to mature and can be harvested for a few weeks off each planting. Depending how much your family eats, you may want anywhere from 1-4 successions each season.
When to Plant
When you plant spinach, mapping out the correct time of year is important. Too late in the year, and you won’t get growth, too early, and it can take longer than you want for the seeds to take root. Let’s take a look at the best timeframes to plant.
The earliest crop will always come from overwintered plantings in the late fall. If you start seedlings indoors about 4 weeks before the last frost, it can be planted as soon as the snow has melted and nighttime temperatures are above 25 degrees.
Spring spinach is best directly sown when soil temperatures reach 40 to 45 degrees. Use a soil thermometer to check your soil temperatures before planting. Seeds germinate best between 45 and 70 degrees Fahrenheit.
Fall spinach should be planted in late summer around the Fall Equinox (when daylight and nighttime are about 12 hours). It can be planted before the equinox if daytime temperatures cool to around 70 degrees or less.
Fall planting successions should ideally be sown every 7-14 days. As the weather cools, it will grow slower and need more time to recover after harvests.
In growing zones 5-9, spinach can be grown nearly year-round. Winter spinach should be planted in the fall 2-3 weeks before the first frost so it can get established before cold temperatures come.
Even in growing zones as cold as zone 3, it will die back to the ground and re-sprout in the spring. Mulching or using row cover may help it spring back as soon as the snow melts.
Prepare Soil for Planting
Like most vegetables, spinach prefers a loose aerated soil that has been amended with compost. To prepare the garden, broadfork garden beds and add 1-2” of compost on the top of the bed. Optionally, you can add all-purpose granular organic fertilizer to the soil before planting.
Overall, it is a light feeder that doesn’t require a ton of fertility, however, worm castings or trace minerals like kelp can drastically improve performance in your garden.
You can direct seed by hand or with a push-behind seeder. Spinach seeds are fairly large like beets and easy to see, making it simple for beginners to achieve optimal spacing.
To begin, use your finger or the back of a shovel handle to make a shallow furrow in the soil, about ½-¾” deep. Pour some seeds into your hand and place them in the furrow.
Baby Spinach: 3-5 seeds per inch, rows 2-4” apart
Full Size: 8-10 seeds per foot, rows 12-18” apart
Remember, spacing spinach too closely could result in crowding and poor yields. But spacing it too far apart means more weed pressure and less utilized garden space. Find a happy medium that works for your space availability and the type you are growing.
How to Transplant Spinach
Spinach seeds can be started indoors to get a head start on the season in the spring. As early as a month or more before the last frost, prepare a 6-pack of 128-cell seedling trays with an airy organic potting mix that includes compost and perlite.
Sow 1-2 seeds per cell at about ½” deep, or twice the dimension of the seed. Gently cover with potting mix and keep moist below lights or near a sunny south-facing window. Do not overwater seedlings, but do not let them dry out. Do not use heating mats, as this plant has a hard time germinating in temperatures over 70 degrees Fahrenheit.
When seedlings reach 2-4” in height and their roots have thoroughly filled out their cells, it is time to transplant in the garden! Use your hands, a trowel, or a Hori planting knife to make a hole and place each cell in the ground, about 4-6” between plants and 6-10” between rows.
Unlike tomatoes and some other crops, seedlings need to be planted at ground level. They should not be planted too deep because you don’t want to bury the growing point. Make sure the roots are thoroughly covered and greens are fully exposed above the soil surface.
Backfill and water in with a watering can and optional diluted fish emulsion fertilizer like Neptune’s Harvest (dilute very well, spinach is not a heavy feeder). Transplanted plants are usually best grown for full-size leaves.
Spinach is a great crop to interplant or companion plant with others in your garden. Companion plants boost each other’s growth and work together to maximize space and soil conditions. Remember, diversity is resilience! Cultivating a diverse garden means more ecological resilience against pests and diseases, as well as more beauty and nutritional value!
Spinach plants well with:
- Swiss Chard Varieties
- Bok Choy
- Salad Greens
Avoid planting with:
There are many varieties of spinach: savoy, semi-savoy, and smooth leaf. Some varieties are bred specifically for fall harvests or for winter growing, others are bred specifically for optimal flavor and texture.
Savoy vs. Regular Spinach
Savoy simply means curled or crinkly textured leaves. Savoy spinach is usually used for cooking, whereas regular smooth-leaf spinach is best for eating raw. Curly savoy leaves are a rich deep green, crisp in texture, and slightly bitter (though they sweeten up significantly after frosts).
Savoy is a more substantial green, denser, and thicker for soups, stews, and winter sautees. Smooth spinach is more neutral and light in flavor, with a thinner leaf texture that is better for eating raw or slightly wilted. Smooth spinach is typically grown in the spring or as tender baby greens.
Savoy and Semi-Savoy Varieties
The curly hardy leaves of savoy varieties are crisp and full, perfect for cooking. Semi-savoy varieties offer the best of both worlds: tenderness for fresh eating, yet enough substance and crinkly texture for cooking.
- Emperor: dark-colored semi-savoy with long stems, great for spring or fall plantings, very resistant to downy mildew
- Hammerhead: medium-green savoy with long, cupped leaves that curl under, quick to bolt so best for early spring and fall sowings, resistant to downy mildew and white rust
- Kookaburra: a fast-growing semi-savoy variety perfect for early spring and fall, great for baby and full-size leaves, resistant to downy mildew
Smooth Leaf Varieties
Smooth leaf spinach is best for fall baby greens or spring harvests. Some of our favorite varieties include:
- Auroch: a fast-growing upright variety with long stems for fall and winter, very resistant to downy mildew
- Gazelle: verdant, semi-smooth, uniform oval or rounded leaves with nice sweet flavor, best for fall and winter harvests, resistant to downy mildew
- Lizard: a slow-bolting plant with smooth oval leaves, great for spring an summer plantings, high yields and quick regrowth after harvest
You may want to plant spinach throughout the fall in hopes of yummy winter sandwiches and nurturing veggie stews! It needs to get established before the first frost, but it stays cold-hardy down to 15 degrees Fahrenheit. In fact, it gets sweeter after a few light frosts.
However, if the plant is too young or is stressed from lack of water or sunlight, it may not be able to survive those frigid temperatures. Plant at least 2-3 weeks before the estimated first frost for your area. Choose an extra cold-hardy variety like ‘Gazelle’ or ‘Hammerhead’ and use a frost protection row cover or a low tunnel to keep your plants protected.
Caring for Spinach
Luckily, this is a relatively low-maintenance and easy to care for plant if you give it the right conditions to thrive.
In terms of irrigation, it’s is not quite as finicky as carrots or tomatoes. Direct seeded planting will need plenty of water to germinate and grow, but once established plants can usually be irrigated 2-3 times per week depending on the weather.
Spinach likes a continuous source of moderate moisture and is more susceptible to bolting and slow-growing if the soil is too dry. In many regions, growing it without irrigation is quite easy because of rainy spring and autumn weather.
Spinach can be watered by hand, with drip irrigation, or with soaker hoses. It can also be overhead irrigated, but downy mildew is an issue in greenhouses or indoor growing if there is a lack of airflow.
Soil and Fertility
Spinach does not need a ton of fertility, but it does love high-quality compost and a slightly alkaline environment (pH over 7.0). It’s sensitive to acidity, which means I usually avoid planting it in areas that have had a lot of woody material like leaves or wood chips (which make soil more acidic).
The most common nutrient deficiency with this plant is boron. It will manifest as small, pale green leaves. They may be deformed or unsightly, and the roots turn dry and dark-colored. This deficiency is common in plant cousins like beets and chard as well. The easiest organic fix is an application of Borax, which is OMRI approved. Use about 1 tablespoon per 100 square feet, dust into the soil, or mixed with 1 gallon of water and watered in.
Be sure your soil is well-drained by using a broadfork to loosen the garden before planting. Microbially-rich compost adds aeration and structure to the soil that helps it thrive. Because it is a shallow-rooted plant, it is very important that there is no surface compaction. Compacted soil may result in stressed yellowing spinach leaves.
Spinach prefers temperatures between 40 and 60 degrees Fahrenheit, but it will tolerate cold as low as 15 to 20 degrees. It gets more delicious as the nights cool and really shines when the rest of the garden starts to fizzle out. Keep in mind that lower temperatures will naturally slow down its growth and you may need to plant more for a continuous fall harvest.
It will tolerate heat as high as 70 to 75 degrees, but quickly bolts when the day length gets longer than 14 hours or temperatures consistently reach above 75. Shade cloth can provide a cooler environment to hold a little longer into the summer.
If you insist on growing in the summer, Malabar spinach is an unrelated alternative that is very heat tolerant and tastes somewhat similar.
Like most greens, spinach prefers full sunlight but can tolerate some shade. It does well interplanting alongside scallions or under young tomato plants. It also works great in container or windowsill gardens as long as it has at least 6” of space and preferably a south-facing window.
Spinach is not prone to many pests, making it an excellent vegetable for beginner gardeners. It is however, succeptible to rabbits, so be aware of your planting space. The greatest threats to a healthy crop are downy mildew, weeds and hot weather.
The only disease that really causes problems in spinach is downy mildew. It is caused by the oomycete Peronospora farinosa f.sp. Spinaciae. This powdery fungus-like pathogen thrives in the humid damp conditions of the northeast and greenhouse tunnels.
It first appears as yellow irregular patches on the leaves and eventually purplish-grey spores on the underside of leaves. It may appear powdery and later dry out and turn the leaves brown. The disease spreads by wind and drafts, especially thriving in humid areas without enough airflow between plants.
Fortunately, most seed varieties are bred for downy mildew resistance. The easiest way to prevent downy mildew is to properly space your plants and harvest regularly. If you start to see downy mildew take hold, remove the infected leaves, and throw them away.
You can use a diluted neem solution as both prevention and treatment to keep the infection at bay. If you have a problem with downy mildew, avoid overhead irrigation as this makes the leaves stay wet for long periods of time. Row cover and drip irrigation or soaker hoses are great options for keeping it free of downy mildew in fall plantings.
If you don’t keep your spinach weeded at the early stages, it will have a hard time competing for sunlight because it is a low-growing plant. Higher density plantings of baby spinach are the best at beating weed pressure. Gardeners should hand weed between plants and use a hoe or wire weeding between rows once a week, or as needed.
Heat and Bolting
Although most of us love to eat this nutritious vegetable in the summer, it does not like warm weather over 75-80 degrees Fahrenheit. If a sudden heatwave comes through, your harvest may bolt and get bitter very quickly. If you are seeding in warm soils above 80 degrees, the germination may be spotty or sporadic.
There are a few bolt-resistant varieties such as ‘Lizard’ and ‘Kolibri’. Keep in mind these varieties are “slow-bolting” but still not completely resistant to hot weather. This is why it’s best to plant spinach only in cooler weather.
How to Harvest Spinach
The crisp crunch of spinach is best experienced within a few days of harvest. Simply grab a handful and cut across the bottom of the stems, leaving the center growing point intact. You can continue to “cut and come again” for at least 3-5 cuts before it starts to slow down.
As mentioned above, I like to plant a new succession every week or two to allow for a continuous new harvest of baby greens. Smooth or semi-savoy varieties are typically best for baby-leaf plantings.
When cutting baby leaf spinach, you can use a serrated Victorinox garden knife to cut at the base of the stems. Hold the leaves back with your hand and cut them in a straight line across. I call this the “mowing” method because it mows the plant almost to the ground. From there, it can grow fresh new leaves in 1-2 weeks.
For full-size spinach leaves, simply let your plants grow for an extra week or two before harvesting. Large leaves can be plucked by hand just like you would harvest kale or chard, being sure to leave a few smaller center leaves in place to keep the plant producing.
Spinach is hardy down to 10 or 15 degrees Fahrenheit. It gets more flavorful as the weather gets colder, but its growth also slows down. For late fall and winter harvests, it’s best to use row cover (a thin protective crop blanket) to keep it a little warmer and protected from harsh winds that may bruise or harden the leaves. The Ag-30 Agribon usually does the trick and can be used as a low tunnel (under hoops) or laying directly over the plant.
If you’re craving some tender greens this autumn, get your spinach in the ground as soon as possible! Spinach is a great crop for beginner gardeners and anyone starting a late garden in the fall.