Spinach (Spinacia oleracea) is an annual leafy green vegetable that grows best in cool weather. There are many different varieties of spinach that range in appearance. Often the leaves are smooth and medium to dark green in color. Spinach plants have an erect growth habit and will produce small yellow-green flowers on spikes in hot weather before going to seed. Spinach is fast-growing and can be ready to harvest in as little as one month after it's planted as seed. In most climates, it grows best when planted in the spring or fall.
|Common Name||Spinacia oleracea|
|Plant Type||Annual, vegetable|
|Size||6–12 in. tall and wide|
|Sun Exposure||Full sun, partial sun|
|Soil Type||Loamy, moist, well-drained|
|Soil pH||Acidic, neutral, alkaline (6.5 to 8)|
|Hardiness Zones||2–11 (USDA)|
|Native Area||North America, Central America, South America, Asia|
How to Plant Spinach
When to Plant
Spinach needs around six weeks of cool temperatures to grow from seed to maturity. That means you should plant seeds in the garden as soon as the soil is workable in the spring. The soil must be cooler than 70 degrees Fahrenheit for germination. Likewise, you can plant in the fall once the temperature cools, as long as you have six weeks where the soil temperature will remain above 40 degrees Fahrenheit. You also can reseed every couple weeks in the spring or fall to extend your harvest.
Selecting a Planting Site
The ideal planting site for spinach is fairly sunny with good soil drainage. Container growth is also an option. As the weather warms, spinach plants will bolt, or send up a flower spike and go to seed. You can slightly delay this by planting in the partial shade of taller plants.
Spacing, Depth, and Support
Seeds can be planted 1/2 to 1 inch deep in rows spaced 12 to 18 inches apart. Once seedlings have grown their first set of true leaves, thin the plants to around 6 inches apart. No support structure will be necessary.
Spinach Plant Care
Plant spinach where it will receive full sun to partial shade. That means it needs at least three to four hours of direct sun on most days, though it could use some protection from strong afternoon sun.
Spinach likes a loamy, organically rich, well-draining soil. And it prefers a fairly neutral soil pH.
Water spinach frequently to keep the soil evenly moist but not soggy. Regular watering is essential in warm weather to prevent bolting. In general, spinach needs around 1 to 1 1/2 inches of water per week. Rather than a weekly deep watering, it's better to water several times a week. Adding a layer of mulch around the plants also can help to maintain soil moisture.
Temperature and Humidity
Spinach prefers to grow in temperatures between 50 and 60 degrees Fahrenheit. It can tolerate a light frost, but heavy freezes will kill the plant. Plus, hot weather will make it bolt and cause the remaining foliage to become bitter. Humidity typically isn't an issue as long as its soil moisture needs are met and there's air flow around the plants.
Because it is such a fast grower, spinach is also a heavy feeder. When planting, mix a fertilizer that's high in nitrogen into the soil, following label instructions. This will help to promote healthy foliage growth. Continue to fertilize throughout the season, following your product's instructions. Fish emulsion and soy meal are good organic choices for spinach.
Spinach is primarily pollinated by the wind, and varieties will cross-pollinate with one another.
Types of Spinach
- Disease-resistant varieties include 'Melody', 'Nordic IV', 'Olympia', 'Tyee', and 'Wolter'.
- Good varieties for fall planting include 'Avon', 'Indian Summer', 'Melody', 'Razzle Dazzle', and 'Tyee'.
- Plants that overwinter well include 'Bloomsdale Long Standing', 'Cold Resistant Savoy', and 'Tyee'.
- Recommended types for containers include 'Baby's Leaf Hybrid' and 'Melody'.
Spinach vs. Kale
Spinach and kale have similar growing requirements, both liking cooler weather and taking around the same time from planting to harvesting. However, they have some clear differences. Kale leaves are typically ruffled with spinach is often smooth. And kale can have a slightly bitter taste while spinach is sweeter.
Typically, you can harvest spinach four to six weeks after planting seeds. Begin harvesting whenever the leaves are large enough for your taste. Spinach can be harvested in the "cut and come again" method. Trim off individual leaves with garden scissors, starting with the oldest outer leaves and letting the young inner leaves remain to continue growing for a later harvest. You also can cut down the whole plant at once if you want a large harvest. If you cut about an inch above the crown, or base of the plant, it is likely the plant will send out a new flush of leaves.
Spinach can be eaten fresh or cooked. The leaves are sensitive to ethylene gas given off by many fruits, so don't store spinach in the refrigerator in the same container as apples, melons, or tomatoes. Keep it in an airtight container on its own. Spinach also can be frozen for later use. Wash the leaves well, and allow them to dry before placing them in a freezer bag. Frozen spinach is best used within three to six months.
How to Grow Spinach in Pots
Growing spinach in containers is a great way to keep it easily accessible for harvesting. And it can help to deter pests from munching on your crop. Choose a container that’s at least 10 to 12 inches deep with a similar width. You also can use a window box for a few plants, depending on their mature size. The container must have drainage holes. Unglazed clay is an ideal material because it allows excess soil moisture to escape through its walls. Note that containers tend to dry out faster than the ground, so you'll likely have to water container plants more frequently.
Harvesting the leaves throughout the growing season is how you prune a spinach plant to keep it vigorous. If a plant becomes diseased or damaged, it's often best to pull the whole plant to prevent it from affecting nearby plants.
Spinach typically is grown from seeds, but it's also possible to propagate plants from stems you pull that still have roots attached. (Taking stem cuttings typically isn't successful.) This skips the germination time that seeds take, allowing you to get a quicker harvest. Here's how:
- As you harvest from mature spinach plants, find a stem that has roots. Gently pull it out of the ground, keeping the roots as intact as possible.
- Plant the stem in a quality potting mix, and water to maintain even moisture.
- Once you feel resistance when gently tugging on the stem, you'll know a strong root system has formed.
How to Grow Spinach From Seed
Aim to plant spinach seeds that are less than a year old, as the germination rate falls the older seeds get. You might have to till your soil before planting, as spinach likes a loose, fine soil. Firm the soil over the seeds, and water to evenly moisten it. Make sure to keep the soil moist during the germination process, and you should see growth in a week or two.
Potting and Repotting Spinach
Use an organic, all-purpose, well-draining potting mix for spinach. It's best to pot in a container that will accommodate the plant's mature size, as spinach doesn't like its roots disturbed in repotting.
In warm climates, you might be able to sow seeds in the fall and harvest well into winter. If the ground freezes before the plants mature, mulch them with hay and leave them be until the temperatures warm again in the spring. Remove the mulch, and the plants should resume growing, giving you an early harvest.
Common Pests and Plant Diseases
Because spinach is grown when the weather is cool and damp, several fungal diseases, such as downy mildew (blue mold) and fusarium wilt, can become problems. Space your spinach plants so they get good air circulation, and try to keep water off the leaves in the evening.
Aphids also pose a risk to spinach because they can spread viruses. Monitor your crop for aphids regularly, and hose them off immediately if you find them. Plus, wild animals, rabbits chief among them, also might raid your spinach patch. The best defense against them is fencing.
Is spinach easy to grow?
Spinach is easy to grow as long as it gets cool weather and sufficient moisture.
How long does it take to grow spinach?
Spinach is typically ready to harvest in four to six weeks after planting.
Does spinach come back every year?
Spinach is an annual, completing its life cycle in one growing season.