Spinach is one of the fastest-growing, most vitamin-packed crops you can grow at home, and it seems like you can throw it in just about any dish! Read on to learn how to grow spinach from seed, how to get the most out of your crop with proper storage, and how to choose the best varieties for your garden.
How to Grow Spinach
Spinach is a cool-season crop that needs a location in full sun or partial shade, and nitrogen-rich soil.
When to Plant Spinach
Spinach is very cold-hardy, but not very heat-tolerant. It needs soil temperatures of at least 40 degrees to germinate, and at least six weeks of cool weather to mature. The best times to seed spinach are as soon as the soil becomes workable in early spring, and in late summer or early fall when the soil temperature is no higher than 70 degrees. You can seed in successions two weeks apart throughout early spring and fall to extend your harvest. A bit of shade can keep plants cooler and help extend your spinach season a little longer into the summer, but no variety will tolerate midsummer heat, so avoid seeding in late spring or early summer.
How Long Does Spinach Take to Grow?
Generally, spinach is ready to harvest 45 to 50 days after seeding. Expect a bit slower growth if temperatures are particularly cold, or if you’re growing in a location with less than full sun.
How to Plant Spinach
Spinach is usually direct-seeded, since the seedlings are delicate and can be difficult to transplant. Plant your seeds one half-inch deep, and about two inches apart. Once the seedlings get their first true leaves, thin them to about four to six inches apart.
Maintaining Your Spinach Crop
A spray of fish emulsion or compost tea can help give your seedlings a boost as they get established, but if you have good nitrogen-rich soil already, this isn’t necessary. Make sure your soil has been amended with compost before planting.
Regular watering is important, since spinach has shallow roots that can dry out quickly. Try to water in the morning, to make sure the leaves dry off quickly, which prevents fungal disease.
Spinach’s shallow root system also means it’s important to be very careful when weeding. The plants’ roots are easily disturbed by cultivation or pulling out weeds around them. It’s a good idea to prevent weeds from the start by mulching around your spinach plants.
Pests and Diseases
Spinach can fall prey to many insects and diseases, but by far the most common problems are aphids and downy mildew. Keep a close eye out for aphids, which look like tiny green or yellow dots on the leaves. They leave behind sticky yellow frass (that’s the fancy term for insect poop), and can cause leaves to grow in misshapen forms. To get rid of them, spray them off with the garden hose, or spritz the leaves with a little soapy water. Keeping your spinach under row cover can also keep aphids and many other insect pests away.
Downy mildew is a fungal disease that thrives in moist conditions. It causes yellow spots on the tops of the leaves, with telltale fuzzy white growth underneath. The best defense is proper plant spacing to allow airflow around the leaves, and carefully timed watering, to prevent the leaves from staying wet for too long. Crop rotation can also help, but downy mildew spores are windblown and can travel vast distances, so many places, particularly in the Southeast, will experience pressure from this disease every year, even if the spores didn’t overwinter in your local soil. If you have a lot of trouble with downy mildew where you're growing, very early or late season crops are more likely to be successful, since the disease usually arrives with warm weather.
When and How to Harvest Spinach
Spinach can be harvested at baby leaf size for salads in as little as 30 days, or at full maturity for use in cooking. You can choose whether to harvest the whole plants at once, or pick a few of the largest leaves from around the edges of each plant and allow the plants to keep growing. Once you see any signs of bolting (flowering), harvest the whole plants immediately. Spinach will begin to grow a central flower stalk and the whole plant will start to get taller when it’s ready to flower. Heat is the main trigger for bolting, so you can slow down the process a bit by keeping your plants cool by watering regularly and providing a little shade.
How to Store Spinach
Spinach leaves are fairly delicate and will only store a few days in the fridge. It’s best to store them unwashed, and only wash them when you’re ready to use them. Excess moisture is the enemy, and wet leaves will begin to rot much sooner. Freezing is the best way to store spinach for the longer term. To freeze your spinach harvest, just blanch the leaves in boiling water for two minutes, then drain them and immediately transfer to a bowl of ice water. Once the spinach has cooled, squeeze out the excess water, put it in freezer containers, and pop it in the freezer.
Best Spinach Varieties to Grow
This reliable, classic variety is one of the most popular varieties of spinach for gardeners everywhere. Very productive, with deep green, crinkled leaves. “Long Standing” refers to its relatively good heat tolerance, making it slower to bolt in warm weather than many other varieties.
As the name suggests, this variety is known for being especially cold-hardy. This is the ideal spinach for planting in late fall for winter harvest.
Noble Giant is known for staying very tender even at fully-grown size, making an ideal choice if you prefer your spinach in salads.
This more heat- and drought-tolerant variety is ideal for spring planting, and good for fresh use in salads, or cooked.
What about “Summer Spinach?”
If you’ve spent some time looking at seed catalogs, you’ve probably seen some varieties called “summer spinach.” These are not true spinach, they’re different species of greens that can be used similarly to spinach, but perform well in the heat of midsummer. Types include Malabar Spinach, New Zealand Spinach, and Nigerian Spinach (Sokoyokoto). If you want to harvest nutritious, fresh greens even in the dog days of summer, explore these alternative options!
Ready to plant your own spinach? Shop our full collection of spinach seeds here. Missed the cool season window, but still hungry for fresh greens? Get some inspiration for summer greens to grow on our blog, or expand your salad greens palate with our guide to 10 Types of Salad Greens and How to Grow Them.