Spinach is a true super-green, both in the garden and in the kitchen. It’s quick and easy to grow and rewards your efforts with an abundant harvest of incredibly nutritious spinach leaves. Read on to learn everything you need to know about how to grow spinach from seed.
Like other leafy greens, spinach is a cool-season crop that grows best in the early spring and fall when temperatures are lower. Spinach, or Spinacia oleracea by its botanical name, is in the Amaranthaceae plant family with beets, quinoa, and Swiss chard.
It’s packed full of nutrients like calcium, iron, potassium, magnesium, and vitamins A, B, C, and K. In most growing climates, it’s possible to enjoy both a spring and fall crop of tasty spinach greens.
Best Tips for Growing Spinach from Seed
Since it grows best in cool weather, plant spinach seeds as soon as you’re able to work the soil for a spring harvest. The same is true for when to plant collard greens. Spinach is a fast-growing crop, and most varieties are ready to harvest within six weeks of planting seeds.
To determine when to plant spinach seeds, you need to know the last frost date for your area. Begin growing spinach from seed about four to six weeks before that date, or whenever the soil temperature is consistently 35℉ or above.
However, germination takes longer in cold soil. When choosing a location to grow spinach, ensure that the soil is well-draining and rich in organic matter.
Spinach tolerates temperatures down to 20℉ but starts to suffer when the weather gets above 75℉. In areas with hot summers, planting spinach seeds as soon as you can work the soil in early spring is best.
Spinach plants are heavy feeders, so adding compost to your soil before planting helps provide nitrogen for the developing seedlings. Plant spinach and take care of growing broccoli from seed with other cool-season veggies like cabbage, radishes, and turnips.
Spinach plants tolerate partial shade, but they grow best in full sun like collard green plants, where they receive at least six hours of direct sunlight daily. Although some spinach varieties are more heat tolerant than others, spinach tends to bolt in hot weather.
In climates with hot summer temperatures, try growing similar greens with better heat tolerance like Malabar or New Zealand spinach.
Although they’re different species, they have a similar taste and texture to true spinach and sometimes are referred to as “summer spinach.”
How to Grow Spinach from Seed
Have you ever wondered how to plant spinach seeds or how you go about planting beet seeds? When growing spinach from seed, timing is crucial. If you sow seeds too late in the season, the plants are likely to start bolting before you get much of a harvest.
In most cases, it’s best to sow spinach seeds directly in your garden beds rather than starting them indoors like when transplanting asparagus seedlings. They grow quickly enough that there’s no significant advantage to starting them indoors.
In freezing climates, it’s advantageous to use a cold frame early in the season to give your spinach seedlings a head start. Similarly, using a cold frame in the autumn is a great way to extend your growing season once the long days of summer are gone. There is no difference between kale and spinach regarding when to plant them.
About a week before planting spinach from seed, apply a generous layer of compost or dark-colored mulch to your soil to warm it up ahead of planting.
The ideal soil temperature for germinating spinach seeds is 50-60℉. For faster germination rates, soak the seeds in water overnight to break down their protective outer coating. Do so about a week before planting, then let them dry completely.
Plant spinach seeds a half-inch deep and cover them lightly with soil. Spacing between seeds should be about one inch. Gently water the garden bed, taking care not to disturb the seeds.
Keep the potting soil moist while the seeds germinate. You’ll begin seeing the spinach seedlings emerge in approximately five to ten days. It sometimes takes up to three weeks at colder temperatures.
Once the seedlings reach two inches tall, thin them out so the spacing between plants is three to four inches. If there were any areas where your spinach seeds didn’t germinate, try transplanting the seedlings you pick.
When considering how to plant spinach seedlings, keep as much of the roots intact as possible. Use your finger to create a one-inch-deep hole in the soil and gently press the seedling into place.
Ideal Growing Conditions for Spinach
For best results, grow spinach in an area with well-draining, rich soil that receives a minimum of five or six hours of direct sunlight each day. It’s also beneficial to fertilize your spinach plants regularly with an all-purpose organic fertilizer.
If you’re using liquid fertilizer or fish emulsion, apply every two or three weeks according to the instructions on the product label. For granular fertilizer, apply every four to six weeks.
While spinach requires consistently moist soil, it’s critical not to overwater. Spinach plants are sometimes prone to fungal diseases, which become much worse in overly wet conditions.
Mulching around your plants helps retain moisture and keeps the soil cooler once the weather starts warming. Hot weather and drought cause spinach plants to bolt, meaning they stop leaf growth and produce a flower stalk.
When this happens, the leaves turn bitter. For a continuous supply of fresh spinach, plant seeds every two weeks through mid-summer and harvest the whole plant before it bolts. Sow another round of spinach seeds in late summer for a fall harvest.
How to Plant Spinach Seeds in Pots
If you don’t have a veggie garden or raised beds at home, don’t worry. Spinach is an ideal candidate for container gardening, whether you follow the way to grow spinach indoors or out. Sow spinach seeds directly in the pot or purchase nursery-grown seedlings from your local garden center.
Choose a pot that’s at least six inches wide and deep with drain holes at the bottom. Fill the pot with nutrient-rich, well-draining potting soil to an inch below the rim. Saturate the soil, then sow seeds a half-inch deep and cover them lightly.
If you purchased the plants and you’re wondering how to plant spinach seedlings, it’s pretty straightforward. Create a hole in the soil that’s slightly larger than the root ball.
Add a teaspoon of organic fertilizer to the bottom of the hole and fill it in with soil. Water the plants immediately after transplanting.
Keep the potting soil consistently moist but not waterlogged. Find a sunny sheltered location on your deck or patio for your spinach pots, or grow spinach indoors on a sunny windowsill.
Depending on which variety you’re growing, spinach is ready to harvest in 35-45 days. Baby spinach greens have a sweeter flavor than the larger leaves. Begin harvesting the outer leaves once a rosette forms with at least six two-inch leaves.
For best results, pick the spinach leaves within a week of full formation. Harvest the entire plant before it begins bolting, or the leaves turn yellow and bitter.
Spinach stays fresh in the refrigerator for up to a week. If you have lots of spinach at the end of the season, consider freezing it. If you’ll be using your frozen spinach within six months, blanching isn’t necessary.
Best Spinach Varieties
One of the best things about homegrown veggies is that there are so many different varieties to try that aren’t usually available at the supermarket.
Spinach varieties are classified as savoy with curly leaves, semi-savoy, and flat-leaf. Here are some of the best varieties of spinach to plant in your garden.
Pest and Disease Issues for Spinach
Although spinach is generally easy to grow, there are a few pest and disease problems to watch out for. Plants are more susceptible to attacks from insects and pathogens when they’re stressed.
Ensuring that they receive adequate amounts of light, nutrients, and water is the best defense. Aphids, leaf miners, slugs, and spider mites are some of the most commonplace insects that feed on spinach plants.
To combat aphids, leaf miners, and spider mites, spray all plant parts with an organic insecticide like neem oil or insecticidal soap. Diatomaceous earth and crushed eggshells deter slugs.
Using row covers in early spring helps prevent insects from laying eggs on the tender seedlings.
Spinach plants are sometimes susceptible to downy mildew, powdery mildew, rust, and mosaic virus. Fungal diseases like mildew and rust are most prevalent in warm, moist environments.
Ensure that your plants have adequate airflow and use drip irrigation to keep water off the leaves. Treat the affected plants with organic copper or sulfur fungicide.
Unfortunately, there is no remedy for the mosaic virus. Immediately remove infected plants, practice crop rotation, and grow disease-resistant varieties.
If you’ve been wondering how to plant spinach seeds, know that it’s worth the effort. Spinach is an excellent addition to the veggie garden for beginners and experienced growers alike.
This cool-season crop is fast-growing, low-maintenance, and highly nutritious. You’ll be harvesting delicious baby spinach greens in as little as three weeks.
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