Overview
Spinach (Spinacia oleracea) is a cold hardy annual related to beets and Swiss chard that has been a long history of use by humans. Native to southwest Asia, it was first cultivated in Persia (Iran) over 2,000 years ago and used by the Chinese in the 6th century. Arabs brought it to the Spanish around the 11th century and it had spread to the rest of Europe by the 14th century. It came to the Americas with the early colonists.
The plant grows a rosette of dark green leaves, but under warm temperatures and long day length it bolts and goes to seed. The leaves may be eaten fresh or cooked, and are highly nutritious.
Varieties of Spinach
There are two basic types of spinach, those with smooth leaves and those with crinkly (or savoy) leaves. The smooth types are normally grown for freezing and canning because they are easier to clean. The savoy types have thicker leaves with more texture, though they take more effort to clean, as the wrinkled leaves tend to need more washing to remove clinging soil. Semi-savoy types are intermediate and have lightly crinkled leaves.
Some newer varieties of spinach are slow bolting (seed-stalk development is slow even as day length increases), so they may be desirable for summer crops. Older varieties without this trait are best used for spring or fall plantings.
The old rule of thumb was that prickly-seeded varieties were best for spring and fall, while round-seeded varieties were better for summer. However, this is no longer true, as new varieties of slow-bolting, round-seeded types have been developed.
Cultivars of Spinach
Some commonly available cultivars include:
- ‘Acadia’ (45 days) is a hybrid, slow bolting, semi-savoy type with good cold tolerance. Highly resistant to downy mildew.
- ‘Avon’ (44 days) is a semi-savoy type for early spring planting. It has large, slightly crinkled, dark green leaves and has resistance to blight and mildew.
- ‘Bloomsdale Longstanding’ (48 days) is an older variety and one of the best tasting but has no disease resistance. It grows erect, with thick, very crinkly, glossy dark green leaves. It is good for late spring and early summer harvest, and will often overwinter with mulching. Other Bloomsdale types have been selected for earlier maturity and slow bolting.
- ‘Indian Summer’ (35 days) is a hybrid, savoy leaf, slow bolting variety.
- ‘Melody’ (42 days) is a 1977 All-America Selection winner with tender, dark green, lightly crinkled leaves with superior flavor. It has tolerance to downy mildew races 1 and 2 and is resistant to cucumber mosaic virus. It grows quickly to a large plant, so is good for spring or fall plantings.
- ‘Monstrueux de Viroflay’ (sometimes listed as ‘Viroflay’, 50 days) is a French variety from at least the mid 1800s with large, smooth, dark green leaves that grow 8 to 10 inches long.
- ‘Olympia’ (46 days) has smooth, dark green leaves. It is very fast-growing but is also very slow to bolt, so is good for spring and early summer planting. It is resistant to downy mildew races 1, 2, and 3.
- ‘Red Snapper’ (28 days) is a hybrid baby leaf type with unusual, deeply lobed leaves with red veins and petioles.
- ‘Regal‘ (30 days) is a semi-savoyed variety suited to dense plantings for baby leaves. It is resistant to downy mildew races 1 through 7.
- ‘Space’ (39 days) is a hybrid, smooth-leaved, bolt-resistant variety with resistance to downy mildew. It has a thick leaf that doesn’t bruise as easily as some types, even when small. Good for both baby spinach and full size plants. Downy mildew resistant.
- ‘Tarsier’ (27 days) is a hybrid, vigorous, semi-savoy type with good bolt resistance. Suitable for planting in any season. Restistant to downy mildew and Stemphylium leaf spot.
- ‘Tundra’ (27 days) is a hybrid, semi-savoy variety with elongated leaves that is good for spring, early summer, or early fall planting. Downy mildew resistant.
- ‘Tyee’ (39 days) is a fast-growing savoy type with thick dark green leaves, similar to Melody. The upright growth habit helps produce cleaner leaves. It is very slow to bolt and is resistant to downy mildew races 1 and 3.
Warm Season Spinach Alternatives
Because spinach rapidly bolts and has reduced leaf quality during the long, hot days of Wisconsin summers, some warm season alternative crops are a better choice for spinach-like greens in summer.
New Zealand spinach (Tetragonia tetragonioides or previously T. expansa) is a New Zealand native in the completely different plant in the Aizoaceae family. A tender, spreading annual, it grows stems 2 to 4 feet long. Its dark green leaves are smaller and fuzzier than regular spinach, but when cooked are very similar in flavor and texture.
Culture is the same as for regular spinach, except it should be planted 1 to 2 inches apart after the soil is warm and the multiple seedlings from each seed cluster should be thinned when the seedlings are large enough to handle. Pinch off the ends of the stems of large plants to encourage new growth.
Other warm season spinach alternatives include Malabar spinach (Basella alba), New Zealand spinach (Tetragonia tetragonioides), and Chinese or African spinach (Amaranthus tricolor, sometimes listed as A. gangeticus).
Growing Spinach
Spinach is a cool-season crop best planted in early spring, about 4 weeks before the average date of last frost. Ideal spinach weather is 50 to 60 °F. Spinach does best in well-drained soil rich in organic matter and will tolerate partial shade. Plant seeds 1 to 4 inches apart and about ½ inch deep. If you use the closer spacing, thin when the leaves touch, when the plants are about 2 inches tall, using the tender leaves for salad greens.
Make sequential plantings about 2 weeks apart to continue harvesting spinach through the summer. Choose bolt-resistant varieties for later plantings. But even slow bolting types will not remain vegetative for very long in warm, long day conditions of summer, so each planting’s productive time will be short. Leaf quality declines when the reproductive cycle begins with seed-stalk formation.
A fall crop often tastes better than the spring crop because the temperature cycle of warm to cool weather is more predictable. Plant a fall crop in mid-August for a late-September (or later) harvest. Extend the season by covering the plants during really cold nights or grow in a cold frame.
You can also try a “winter” crop, planted in late September, that will grow a little before going dormant for the winter. Alternatively, just cut off the leaves of the plants of your fall crop, leaving the roots and growing point intact. These plants may overwinter to grow a new crop of leaves in the spring. In colder areas or severe winters, covering the plants with mulch will enhance their survival. Some varieties, such as ‘Bloomsdale Long Standing’, are hardier than others, and are more likely to survive the winter.
Spinach seed does not remain viable for very long, so purchase seed packaged for the current year. Storing seed under optimal storage conditions (cool temperatures and relatively low relative humidity) allows it to remain viable for a couple of years, but germination rates will typically be reduced.
Spinach Culture
Grow spinach in fertile, moist, well-drained soil. Dry, infertile soil encourages spinach to bolt and go to seed. Spinach does best with uniformly moist soil, but it is best to avoid splashing water so the leaves won’t get so dirty. You can mulch around the plants to help retain moisture and keep soil off the leaves.
Spinach is a weak competitor, so keep spinach plantings weed-free. Pull tiny weeds or cut off larger ones at ground level to avoid injuring the shallow roots of the spinach plants.
Spinach is a heavy feeder. Fertilize before planting and at midseason to stimulate growth and yield. This is more important in spring when nitrogen is less available to plants in cold soil. Apply a side dressing or liquid fertilizer when plants are about 2 inches tall. If the leaves begin to yellow, fertilize again with a nitrogen fertilizer.
Spinach Pest Management
There are few insects or diseases that bother spinach. Aphids may occasionally infest plants and spinach leafminer may be problematic in some areas. Aphids can be controlled by removing infested leaves or with with a vigorous stream of water. Minor infestations are often controlled by a variety of natural enemies, such as green lacewings, lady beetles, and parasitic wasps. High populations may be treated with insecticide labelled for aphid control on spinach. Always read, follow, and understand label directions when using pesticides.
Spinach leafminer is a fly that lays its eggs on the undersides of the leaves. Maggots burrow into the leaf and create conspicuous trails as they eat their way through the leaf. Remove leaves with eggs or mines. Pesticides are not effective against the larvae once they move inside leaves. To prevent leaf miner damage, cover plants with floating row covers after thinning. Use supports, such as hoops, to keep the fabric off of the plants. Unlike other plants which tolerate row cover placed directly on the plants, the tender spinach leaves can be abraded if the fabric brushes back and forth in windy conditions.
Slugs can also be a problem in very moist situations. When slugs are a problem, do not mulch around the plants. Spinach is susceptible to rust but most varieties are rust resistant. Occasionally leaf spots, either Cercospora leaf spot or Anthracnose, may develop on the upper sides of the leaves, then fall out to form holes. Fungicides will control these diseases. Choose resistant varieties if downy mildew is a problem in your garden.
Harvesting Spinach
Individual leaves can be harvested periodically starting when the plants have at least 6 true leaves, or entire plants can be harvested at maturity. This is probably the best harvesting method in the spring or when a central stalk begins to appear.
Cutting the plants off at the soil line will keep the harvested leaves cleaner than if the whole plant with its roots is removed. In the fall, removing the outer leaves only will allow the plant to continue to grow and produce more for continued harvest.
Wash the leaves thoroughly in plenty of water to eliminate all grit that sticks to the leaves, especially the crinkled types.
Fresh spinach can be refrigerated for up to one week. The leaves can also be frozen, canned, or dried.
Author: Susan Mahr, University of Wisconsin-Madison
Reviewers: Allen R. Pyle, Horticulture Outreach Specialist, UW-Madison Extension, Bruce Spangenberg, Horticulture Outreach Specialist, UW-Madison Extension
Revised: October 2026
