How to Grow Spinach: Planting, Growing, Harvesting
Spinach is one of the first vegetables you can plant at the start of the growing season. It prefers cool weather, well draining soil, and full sun, but can also tolerate some partial shade. Fast-growing and low-maintenance, it’s a great crop to have in your garden, raised beds, even straw bales and containers.
In this guide, we’ll take an in-depth look at the spinach growing conditions, starting with how to grow spinach from seed, how to water and fertilize your spinach plants, when and how to harvest them, and how to store them so that you can enjoy tasty spinach throughout the year.
Spinach Varieties You Can Grow
There are three main spinach types found in cultivation: Savoy, semi-Savoy, and smooth-leaf. Let’s take a closer look.
- Savoy spinach: Like the Savoy cabbage, this variety has curly, crinkled leaves that can grow up to 6 inches (15 cm) in size. Its dark green leaves also have a more bitter taste and chewy texture, better suited for cooking rather than eating raw. Popular cultivars include Bloomsdale and Regiment.
- Smooth-leaf spinach: The best-known variety, it has smooth, unruffled leaves. Its mild taste and tender leaves make it ideal for salads and garnishes, and it’s best enjoyed raw or very lightly cooked. This variety is usually picked when young, and it’s what you’ll commonly find sold as baby spinach in supermarkets.
- Semi-Savoy spinach: Halfway between Savoy and smooth-leaf spinach, the leaves of this variety are less crinkled. They pack a more noticeable aroma than the smooth-leaf, but without the bitterness of Savoy. A hardy variety, it’s less likely to bolt than other types of spinach.
You’ll also come across other species that, although not spinach plants in a botanical sense, still share the same common name. The best thing about them is the fact that they are more heat-tolerant than regular spinach, so you can use them as a summer alternative. Here are a few you can try growing:
- Malabar spinach: A tropical edible vine, it has the same mild, peppery taste as spinach. Easy to grow on trellises or up a fence, it’s a great pick for gardens that don’t provide too much space, and for gardeners living in hot, humid climates.
- New Zealand spinach: A summer crop, this plant loves sun, warmth, and moist soils. The leaves have a bitter, lettuce-like taste, and can be used the same way as spinach leaves. Plant it in late spring, and get ready to harvest it in about 7 weeks.
- Strawberry spinach: It’s neither spinach nor is it strawberry. Its leaves look very similar to arugula and have a mild, spinach taste. This plant produces bright pink berries that are also edible, but only mildly sweet and with a noticeable tartness.
When Is the Best Time to Plant Spinach?
Spinach is a cool weather crop, best planted in early spring and early fall. You can start planting spinach seeds once the soil temperature is at least 40°F (4.4°C). Spinach can tolerate a light frost, and in warm climates, you can also plant it throughout winter. Hot weather is the main thing you’ll need to avoid when growing spinach. If temperatures exceed 75°F (24°C), the seeds may fail to germinate. Also, high temperatures will cause established spinach plants to bolt.
Plant spinach seeds in early spring, ideally six to eight weeks before the last frost. For a continuous crop, sow a new batch every 10 – 14 days. Take a break from sowing during the hotter months, or sow heat resistant species such as New Zealand spinach or Malabar spinach. You can then sow again in late summer for fall crops.
Where to Grow Spinach
The best location for planting spinach should be a part of your garden that’s sunny and has well drained soil. Although spinach is a cold weather crop, it needs full sun to grow well. It can also tolerate some partial shade, but the seeds will take longer to germinate, and the plants will develop slower. So if you want to grow vigorous spinach, make sure it receives at least 6 hours of sunlight per day, preferably in the morning.
How to Plant and Grow Spinach
Starting your own spinach garden is quicker and easier than you may think. Let’s take a closer look at what you need to know about growing spinach at home.
Prepare the Soil
Spinach grows best in garden soil that’s loamy, well-draining, rich in organic matter, and with a neutral pH. You can use a soil test kit to check the pH, then add lime if the soil is acidic (a pH of less than 6.5) or some sulfur if you have alkaline soil (a pH over 7.5).
Dig your existing soil to a depth of one foot (30 cm) and work in some compost and manure to improve drainage, moisture retention, and nutrient availability. As tempting as it is, never plant spinach directly in compost. Too much compost can increase the level of soluble salts in the soil, which can burn the spinach roots.
Sow Spinach Seeds
Always sow spinach seeds directly in the garden soil or raised bed, as the young plants don’t transplant well. Plant seeds about an inch (2.5 cm) deep and 2 inches apart (5 cm), in rows about 12 inches apart (30 cm). Aim for 4 to 6 spinach plants per square foot after thinning. This will give them plenty of space to develop and provide air circulation, which reduces the risk of fungal diseases. Keep the soil moist and the seeds will germinate in 5 to 7 days.
How much spinach should you plant per person depends on how much you like spinach, and how often you plan to eat it. The recommended daily serving is 4 cups (120 grams) of spinach leaves. That means 8 or 10 plants per person should be enough. Keep in mind that spinach contains oxalic acid and vitamin K, which can be harmful if eaten in large amounts. Realistically speaking, if we ate as much spinach as Popeye, we ‘d likely develop kidney stones.
Two weeks after the seeds germinate thin the young spinach seedlings to 4 inches apart (10 cm). By then, the seedlings should be at least 2 inches (5 cm) tall. Simply grab them from the base and pull them out by hand. The thinnings are edible and make a wonderful addition to a spring salad.
Water your spinach regularly, keeping the soil moist but not soaked. In warm weather, you may need to water it at least twice a week. If you allow the soil to dry out, the spinach will bolt even if the weather is not very hot. A great solution is installing a drip irrigation system with a timer, which will help you keep the soil evenly moist without too much work. You can also add some mulch between the plants to help preserve soil moisture.
Spinach is a heavy feeder. If you’ve planted it in rich, organic soil, it shouldn’t need any fertilizers for the first month after the seeds have sprouted. But after a month, or once you start harvesting the leaves, you will need to give it a dose of water soluble plant food once every 2 – 3 weeks. Fish emulsion is a great choice, or you can use a fertilizer solution that’s rich in nitrogen. Check the instructions on the label for the recommended dosage and how often to apply it.
When and How to Harvest Spinach
Spinach takes around 40 to 50 days to grow from seed. You can start harvesting spinach when the leaves are at least 2 inches (5 cm) in size. Use the cut-and-come-again method to harvest, and start with the older, outer leaves. The more often you pick, the more your spinach will grow, but make sure you leave a few leaves on each plant so that it continues to thrive.
Spinach leaves taste better when young. If you leave it in the soil for too long, spinach begins to turn bitter, and will eventually bolt. When the days get too hot, it’s best to just pull out the plant from the soil and start a new crop later in the growing season.
One of the best things about spinach is that the entire plant is edible — this includes roots and even flowers, if your spinach has bolted. Spinach is best eaten fresh, or lightly blanched, steamed, or sauteed.
You can keep fresh spinach in the crisper drawer of your fridge for a week or so, wrapped in paper towels, and placed in a sealed container. Don’t wash spinach until you’re ready to use it, or it will mold. If the leaves and stems have a bit of garden dirt on them, simply give them a light shake to get rid of the worst bits.
For long-term storage, wash and blanch the spinach leaves for 30 seconds, then keep them in the freezer for up to 12 months. You can also freeze spinach without blanching by putting it straight in a freezer bag. Blanching will help the leaves retain their flavor, color, and texture, so it’s best if you don’t skip this step.
Common Spinach Pests and Diseases
Spinach is tolerant to most pests and diseases, especially when grown in an organic garden. However, spinach crops growing in very damp conditions can be susceptible to plant diseases such as blue mold, downy mildew, and fusarium wilt. To prevent such problems, thin your plants to avoid overcrowding, and harvest the bottom leaves regularly. It’s also best to water your spinach in the morning, preferably from below, using a drip irrigation system or soaker hose.
Common spinach pests include aphids and leaf miners. Aphids are easy to get rid of by hosing down the plants and applying an insecticidal soap solution. For leaf miners, prune the damaged leaves, and if the whole plant is infected, simply pull it out and discard it. You can also use insecticidal sprays such as Spinosad if you’re dealing with severe infestations, but keep in mind that this will also harm beneficial insects such as ladybirds and bees.
Companion Planting With Spinach
One of the best spinach companion plants are beans and peas. Both these crops help fix nitrogen in the soil. If you plant spinach in the early spring, you should be done harvesting it by the time beans and peas grow tall enough to shade it. After you’ve harvested your legumes in early fall, they will leave behind nitrogen-enriched soil, perfect for sowing a late-season spinach crop.
You can also grow spinach together with onions, garlic, tomatoes, eggplants, cauliflower, broccoli, melons, cucumbers, and carrots. Radishes, orache, and lettuce are also great picks, as they have the same growing requirements as spinach, and can be harvested around the same time. If you want to deter pests, nasturtium is a wonderful companion plant for spinach, efficiently keeping it safe from aphids.
How to Grow Spinach Indoors
Spinach is easy to grow in pots. Also, when grown indoors, it’s easier to keep it safe from pests, and you can even enjoy fresh, homegrown spinach in the height of summer. The best varieties to grow for indoor spinach crops are smooth-leaf ones, which mature faster and don’t take up too much space.
To grow spinach in containers, sow seeds 2 inches apart (5 cm) in a quality potting mix, and put the container in a spot where it receives at least 6 hours of natural light. Keep the soil moist and thin the spinach seedlings when they are a week old. Plants should be ready for harvesting 40 to 45 days after sowing.
How to Grow Spinach Without Seeds
The only way to grow spinach without seeds is using the cut-and-come-again method on an established spinach plant. As you harvest, pick as many of the mature leaves as you can, but leave a few of the younger leaves in the center or the crown. Care for the plant as usual, and your spinach will continue to grow.
Growing spinach doesn’t take a lot of gardening know-how. Once you know the basics, you’ll find this an easy-to-grow vegetable that will keep your green fingers busy throughout spring and fall. So now that you know how spinach is grown, it’s time to grab a seed packet and a shovel and start planting your own.