Find out how to grow spinach to make the most of cool weather. Spinach is a quick and nutritious crop for your spring or fall garden! Spinach is a great-tasting early-season green. Next to the dandelion, spinach is one of the first greens that can be harvested in early spring. It is also one of the best fall and winter crops. Here is your complete guide to growing and harvesting spinach.
Spinach is a cool-season annual. Plant spinach before the weather warms in spring and again as the weather cools in early autumn. (When days lengthen in late spring and the weather becomes dry and hot, spinach bolts and stops making new leaves.)
Spinach can be grown under cover in cold weather. Plant spinach in early fall, then cover plants with a plastic tunnel or set plants in a cold frame for a harvest of fresh spinach, both tender leaves cut and come again or the entire plant in winter. Where winters are mild, spinach can be harvested without cover from October to April–when it is not bothered by insects and diseases.
Here is your complete guide to growing and harvesting spinach!
How to Select Spinach Seeds
There are three types of spinach: Savoy, semi-savoy, and smooth leaf. Savoy has crinkly leaves and grows close to the ground, so it can be harder to clean than smooth-leaf varieties. But it’s also more disease-resistant and cold-tolerant and has a pleasantly chewy texture. Semi-savoy varieties are more upright and less crinkly, and most varieties have a good disease and bolt resistance.
Choose your spinach variety according to your priorities, ease of cleaning, harvest timing, or disease resistance. You’ll see a wide variety with “winter” in their name, indicating good cold tolerance. For spring or warm climate planting, choose bolt-resistant types.
Spinach Varieties to Try
- ‘America’ (52 days): crumpled, dark green glossy leaves; mostly heat and drought-tolerant.
- ‘Bloomsdale Long Standing’ (43 days): thick crinkled, dark green, glossy leaves; slow to bolt; mosaic virus tolerant.
- ‘Giant Noble’ (45 days): smooth flat leaves; leaves are large, thick, and pointed; resistant to mosaic virus.
- ‘King of Denmark’ (46 days): rounded, slightly crumpled, dark green leaves; hardy plant.
- ‘Melody’ (42 days) large plant with semi-crinkled leaves; resistant to mosaic and powdery mildew.
- ‘Tyee’ (37-53 days): resistant to downy mildew.
Hot Weather Spinach Alternatives
- Malabar spinach: vigorous climbing vines; native to tropical Asia and Africa.
- New Zealand spinach: grows naturally as a trailing ground cover.
Where to Grow Spinach
- Grow spinach in full sun in spring and autumn in most regions. Grow spinach in partial shade in warm regions.
- Plant spinach in loamy soil rich in organic matter. Adding aged compost to the soil should ensure good drainage. Add two inches of aged compost or a commercial organic planting mix to the planting beds before planting then turn the soil to 12 inches (30cm) deep.
- Spinach prefers a soil pH of 6.0 to 6.8. Spinach does not grow well in alkaline soil.
- Spinach is hardy and thrives in cool weather; ideal spinach-growing weather is 50°F to 70°F (10-21°C).
- Warm weather and long days will cause spinach to bolt—that is it will flower and go to seed.
Spinach Growing Time
- Spinach is a cool-season annual. It needs 6 weeks of cool weather from seed sowing to harvest.
- Spinach grows best when planted outdoors in early spring and then again in autumn. In mild-winter regions, grow spinach outdoors in winter.
- Sow spinach seeds directly in the garden as soon as the soil temperature reaches 35°F and the ground is workable.
- Direct sow spinach outdoors or set out transplants 4 weeks before the last average frost date.
- Sow spinach indoors 6 to 8 weeks before the last average frost date in spring for transplanting out as early as 4 weeks before the last frost. However, seedlings may suffer transplant shock if the roots are disturbed at transplant time.
- Plant succession crops of spinach in spring every 10 to 14 days until daytime temperatures are consistently greater than 75°F. Succession planting will ensure a continual harvest of fresh spinach leaves.
- Long days and temperatures greater than 75°F encourage mature spinach plants to bolt.
- Young plants may bolt if exposed to temperatures below 40°F for one or two weeks after they come up.
- In mild-winter regions, plant spinach in late summer or early autumn for harvest in autumn or winter; sow spinach for autumn harvest 6 to 8 weeks before the first fall frost.
- Spinach can be grown everywhere in a cold frame or plastic tunnel through the winter.
- Spinach planted in autumn can survive the winter under thick mulch; plants will resume growing in the spring. The best alternative is to grow winter spinach in a cold frame or plastic tunnel.
- Temperatures of 20°F or below can freeze leaves and kill plants.
- Don’t grow spinach through the summer in hot summer regions. Instead, grow New Zealand spinach or Malabar spinach, which are heat tolerant.
- Plant spinach seed ½ inch (12mm)deep. Cover the seed lightly with the soil.
- Refrigerate seeds 1 week before sowing to help germination.
- Sow seed 2 to 4 inches (5-10cm) apart.
- Space rows 12 to 14 inches (30-35cm) apart.
- Spinach seed will germinate in 5 to 9 days at 70°F (21°C). Germination will take longer if the soil is cooler, about 21 days at 50°F (10°C).
- Thin spinach to 12 inches (30cm) apart when seedlings are 3 inches (7cm). Thin to the strongest seedlings. Remove weak seedlings by cutting them off at the soil level with scissors.
- Thin spinach so that there is good air circulation between mature plants.
- Grow 15 plants per household member.
Container Growing Spinach
We grow our spinach in the ground and in raised beds. I've even grown it in pots. Allow one plant for each 6-8-inch (20cm)pot; plant spinach in 10-inch (25cm) centers in large containers. In raised beds, spaced out with about 2"-4" between the plants.
If you plan to harvest young leaves or plants, you can grow 4 plants in a 12-inch pot. To harvest mature leaves, grow fewer plants in an area.
Companion Plants for Spinach
Spinach makes a great companion plant for many other greens. Spinach grows well in the shadows of tall crops such as corn, pole beans, or other members of the amaranth family, such as beets and Swiss chard.
Watering and Feeding Spinach
- Keep the soil evenly moist throughout the growing season to grow spinach quickly.
- Water spinach at the base of the plant. The base of plant watering will avoid splashing muddy water onto leaves.
- Mulch around spinach plants with straw, chopped leaves, or garden compost to prevent soil moisture evaporation and avoid splashing soil on leaves.
- Side dress plants with compost tea or a dilute solution of fish emulsion every two weeks during the growing season.
- Side-dress spinach with aged compost at midseason.
Caring for Spinach
- Keep planting beds free of weeds to avoid competition for light, water, and nutrients.
- Cut weeds at soil level rather than digging them out; spinach has a deep taproot but shallow feeder roots that can be injured easily.
- Mature spinach plants can tolerate temperatures as cold as 20°F (-6.7°C), but it is best to protect plants from freezing weather by covering the bed with a portable plastic tunnel or row cover.
- Spinach will bolt in temperatures greater than 75°F (24°C). If the weather warms, try protecting spinach under a shade cloth set over a frame.
How to Extend the Spinach Season
- Plant spinach in a cold frame in late winter (February), and the crop will be ready in early spring.
- Choose heat- and bolt-resistant cultivars.
- Grow spinach in light shade when the weather warms; plants in containers can be easily moved from a sunny location into a cooler, shady location.
- Plant hardy cultivars for fall and winter harvest (check seed packets for hardiness).
- Overwinter spinach plants by covering them with 8 to 12 inches of straw; when daytime temperatures reach 50° to 60°F in spring, gradually remove a few inches of straw each week.
- In warm winter regions, plant spinach in fall as a winter crop.
Pests that Bother Spinach
- Spinach can be attacked by aphids, flea beetles, leaf miners, slugs, and spider mites.
- Knock aphids off plants with a strong blast of water. Pinch out heavily-infested foliage.
- Remove leaves in which leafminers are tunneling-. Look for the eggs on the underside of the leaves. Floating row covers can exclude leafminer flies from the planting bed.
- Spray flea beetles and spider mites with spinosad.
- Use row cover over young plants to exclude attacks by flea beetles and caterpillars. Row covers can remain in place as long as temperatures are moderate.
- Leafminers can spread quickly; till the soil at the end of the growing season to expose leafminer eggs to the winter cold.
- Keep slugs and snails away from spinach by sprinkling a barrier of diatomaceous earth around plants.
- Spinach is susceptible to mildew, rust, and mosaic virus.
- Plant rust and disease-resistant varieties.
- Mildew and rust are fungal diseases. Spray-mist leaves with compost tea to prevent fungal diseases.
- Plants hit by mosaic virus should be removed from the garden. The mosaic virus will cause leaves to be mottled or streaked with white or yellow spots.
- Keep the garden clean of debris. Remove and destroy diseased plants.
- Good air movement discourages fungal diseases such as downy mildew, white rust, and anthracnose.
- Hot temperatures encourage Fusarium wilt and other fungal diseases and promote bolting.
- ‘Melody’, ‘Indian Summer’, and other cultivars resist mosaic virus and downy mildew. ‘Fall Green’ is a white rust-tolerant cultivar.
- Spinach leaves can be harvested as soon as they are big enough to eat.
- Cut leaves 4 to 7 inches (10-17cm) long from plants that have 6 to 8 leaves. Cut the older outer leaves first. Allow the remaining young leaves to grow on to maturity.
- If you harvest all of the leaves from a plant, cut the leaves 3 inches (7cm) above the soil; new leaves will grow for a second harvest.
- Very large leaves and older leaves can be bitter; harvest leaves sooner rather than later.
- Lengthening days (days longer than 14 hours) and warming weather (temperatures greater than 75°F/24°C) will cause spinach to bolt, flower, and set seed. Bolting will mark the end of the harvest.
Storing and Preserving Spinach
- Wash spinach thoroughly to eliminate the grit that sometimes sticks to crinkled leaves.
- Spinach can be refrigerated for up to one week.
- Spinach can be frozen, canned, or dried.
- Spinach seeds can be sprouted.
Spinach in the Kitchen
- Spinach can be eaten raw or cooked.
- The dark green leaves of fresh spinach will add color to a lettuce salad.
- Spinach can be pan-steamed in the water it is rinsed with.
- Stir-fry spinach with garlic or bacon grease.
- Bake spinach with alternating layers of pasta and cheese.
- Add spinach to mushroom soup or cream soup.
- Add spinach to omelets and quiche.
Saving Spinach Seeds
- Spinach is a wind-pollinated, self-fertile annual.
- Spinach will not cross with New Zealand spinach; other spinach varieties will cross when the wind carries the fine pollen.
- Plant spinach varieties apart to avoid cross-pollination or do not allow plants to flower.
- Save seeds from late-bolting plants that are good-sized and abundantly leafy.
- When green leaves turn yellow, pull up the plant and hand-strip seed stalks.
- Spinach seeds will remain viable for about 5 years.
Spinach Frequently Asked Questions
Q: What causes small white cottony blotches on the upper surfaces of spinach leaves (there are usually yellow spots on the undersides)?
A: White rust is a fungus disease that can be controlled with an organic fungicide. Also, avoid overhead watering, which can spread disease.
Q; What causes spinach to become stunted with yellow leaves and twisted leaves and stems?
A: This is caused by a disease called spinach blight or spinach yellow, which is spread by aphids. Grow resistant varieties (check seed packets) and control aphids as soon as they appear.
Q: What causes spinach to flower before it is ready to harvest?
A: Long days and warm summer temperatures force spinach to flower prematurely. Plant earlier in the spring or in the fall, when days are shorter and cooler.
- Spinach is a cool-season annual grown for its leaves.
- Spinach forms a rosette of dark green leaves that can be flat or crinkled (savoy leaf spinach).
- Spinach is related to beets and Swiss chard of the amaranth family.
- Botanical name: Spinacia oleracea
- Family: Amaranthaceae
- Origin: Asia
If your soil’s ready, it’s time to grab those spinach seeds and get planting!
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