Spinach: Sowing, Growing and Harvesting in the Vegetable Garden

Botany

Spinach (Spinacia oleracea) is an annual or biennial plant from the Chenopodiaceae family, like chard and beetroot. This vegetable originates from India and arrived in France during the Middle Ages via Persia.

Etymologically, “spinach” comes from Persian. The genus name Spinacia derives from the Latin spina, meaning thorn, referring to the spiny seeds (of certain varieties). Spinach leaves are arranged in a rosette and have either a rounded or arrow-shaped form depending on the variety. The arrow-shaped form is closer to the wild species (S. tetrandra), while the rounded form is typical of varieties selected by humans.

The leaves are alternate and petiolate, ranging from light to dark green depending on their maturity. A spinach plant reaches about 30 cm in height before flowering. The flower stalks can grow up to 80 cm tall. The plants are dioecious, meaning there are both male and female plants. If left unharvested, female plants bear small, discreet green-yellow flowers, while male plants have more visible flowers with yellow stamens. It is an anemophilous plant (literally, wind-loving), with pollen carried by the wind rather than insects. The seeds are produced by female plants and can be either smooth or spiny depending on the variety.

Spinach in flower

The main varieties

The most well-known varieties

Unusual varieties

Spinach Apollo

This variety, with its thick, fleshy leaves, offers excellent yields. While it has good resistance to downy mildew, it is sensitive to extreme heat, making spring and autumn cultivation preferable for this variety.

• Height at maturity 20 cm

See the product sheet

Spinach Giant Winter - Ferme de Sainte Marthe Seeds

The Giant Winter Spinach is a short-day variety, suitable for autumn and winter harvests. Its large, dark green leaves will provide much-appreciated greenery during the winter months.

• Height at maturity 3 m

See the product sheet

Spinach Picasso F1

The Picasso Spinach produces an abundance of small, rounded dark green leaves, ideal for eating as young spinach shoots—better suited for salads than cooking. This variety is highly resistant to bolting.

• Height at maturity 20 cm

See the product sheet

Spinach Viroflay Giant- Ferme de Sainte Marthe seeds

The Monstrueux de Viroflay Spinach is, as its name suggests, vigorous! It forms beautiful clumps of large leaves, and its flavour is not compromised by its generous yield.

• Height at maturity 50 cm

See the product sheet

Spinach Samos F1

The Samos F1 Spinach is a variety with broad, fleshy leaves, ideal for spring and autumn harvests. Its advantages are numerous: it resists bolting, provides good yields, and its leaves freeze well!

• Height at maturity 40 cm

See the product sheet

Spinach Junius - Vilmorin seeds

This variety has tasty leaves and is ideal for summer harvests, as Junius is highly resistant to bolting. It also shows good disease resistance.

• Height at maturity 40 cm

See the product sheet

Spinach Matador Organic - Viking Spinach

The Matador Spinach, also known as Viking Spinach, is a long-day variety with arrow-shaped, thick, dark green leaves. It can be grown year-round, offers generous harvests, and is slow to bolt.

• Height at maturity 3 m

See the product sheet

Spinach Parys F1 - Vilmorin Seeds

Parys F1 is a variety selected from the Giant Winter Spinach, producing large green leaves also suited to autumn and winter harvests. It offers improved disease resistance.

• Height at maturity 50 cm

See the product sheet

Organic Patience Dock - Rumex patientia

Spinach dock, better known as perpetual spinach, is not botanically a spinach but a type of sorrel. However, it is less acidic than common sorrel and can be eaten raw or cooked. A definite advantage—it's a perennial plant!

• Height at maturity 30 cm

See the product sheet

New Zealand Spinach - Tetragone - Tetragonia tetragonioides

New Zealand Spinach is not, botanically speaking, a true spinach but a distinct species also known as Tetragonia. It is a very vigorous plant with a more iodine-like flavour. Although more drought-resistant, it is less tolerant of cold.

• Height at maturity 60 cm

See the product sheet

Growing Spinach

What type of soil is best for growing spinach?

Spinach thrives in firm, well-drained yet moisture-retentive soils that are rich in nutrients, particularly nitrogen and potassium. It requires well-manured ground. Ideally, in autumn, incorporate mature compost (around 3 kg per m2) by lightly forking it into the top 5 cm of soil.

When is the best season to grow spinach?

All seasons are technically possible for spinach cultivation, though it performs best in spring and autumn. Late autumn sowings can yield winter harvests (in milder regions). Summer is the least favourable season for this leafy vegetable, as it tends to bolt. Not to worry – long-day varieties are better suited to these challenging conditions.

Where should spinach be planted?

For spring and autumn-winter crops, choose a sunny spot. Summer cultivation benefits greatly from shade – provided by a wall or taller crops (such as tomatoes), especially in southern France.

When and how to sow spinach?

When to Sow Spinach?

Spinach can be sown:

• from February to June (long-day varieties such as ‘Matador’, ‘Junius’)
• then from late August to October (short-day varieties such as ‘Giant d’Hiver’, ‘Apollo’)

How to Sow Spinach?

Spinach is mainly sown directly in the ground in rows. It can also be broadcast sown.

• On fairly firm soil, lightly raked, draw furrows spaced 25 to 30 cm apart, 1 to 2 cm deep,
• Sow in rows, spacing the seeds 3-4 cm apart,
• Cover the seeds with soil and “firm” the sowing by tamping the soil with the back of a rake,
• Water gently and keep moist – but not excessively – until germination.

After germination, thin out by keeping only one plant every 10 cm. Fill any gaps with the strongest removed seedlings.

Growing Under Cloches or Cold Frames

For the first sowings of the year in February and March, I recommend placing a polytunnel over your spinach rows to gain a few degrees, thus speeding up germination, enhancing growth, and bringing forward the harvest period. The same applies to the last sowings in late October.

1) Germination of spinach seedlings sown broadcast. 2) Growing under a cold frame

Spinach Care

To ensure abundant harvests, spinach requires constant moisture. Carry out regular watering or better still – take advantage of the natural humidity of the shoulder seasons.

Other necessary care includes regular weeding or hoeing during the first few weeks – while it’s still easy to work beneath the leaves, then once the soil has warmed sufficiently apply a mulch that decomposes quickly, such as dried grass clippings.

Pairing

Spinach belongs to the Chenopodiaceae family, which is why I recommend avoiding growing it near species from the same family such as orache, beetroot, and Swiss chard.

Once this precaution is taken, it is a good neighbour that thrives alongside many other vegetables. In fact, it forms the basis of a well-known companion planting method: Gertrud Franck’s method.

Gertrud Franck’s Companion Planting Method

Mrs Franck developed a famous companion planting method in which spinach is the key plant!

In this method, all crops are sown in rows, and between each vegetable row is a row of spinach. The latter not only serves as a food crop but is also considered a green manure. And that’s the brilliance of this method! Spinach, being a “nitrate pump,” draws residual nitrogen from the soil and incorporates it into its composition. Before flowering, it is mowed and lightly worked into the soil. A vegetable row is then sown or planted where the spinach row previously stood, benefiting from the nitrogen (and other nutrients) released back into the soil by the spinach.

One of my spring beds where spinach grows harmoniously with various types of cut-and-come-again lettuces. Perfect for colourful, textured mesclun mixes with the addition of some crunchy peas (on the right).

Common diseases

Spinach Downy Mildew

Downy mildew is the most common and virulent disease affecting spinach – it appears as yellow spots on the upper surface of leaves and a purple downy growth on the underside. Spinach downy mildew is a fungal disease caused by the pathogen Perenospora farisonosa f. sp. spinaciae, with 7 different strains currently identified. Downy mildew primarily occurs in spring and autumn, thriving in cool, humid conditions (15-20°C).

Tips to prevent and manage downy mildew:

• Keep a close eye on your crops by inspecting them regularly. If leaves show yellow spots, check their undersides. If you detect purple downy growth, carefully remove affected leaves to prevent spreading spores to healthy foliage.
• Practice crop rotation, avoiding planting spinach in the same bed for at least 3 years.
• When possible, avoid watering the foliage: water your spinach plants between rows rather than directly on them.
• If growing under cover, ensure proper ventilation to reduce humidity.
• For recurrent infections, grow downy mildew-resistant varieties such as ‘Palco F1’

Harvesting spinach

Spinach is harvested leaf by leaf, depending on their growth and culinary needs. The outer leaves of the plant are cut first, which prevents damage to the heart that continues to grow and produce new leaves. The entire clump is harvested when the plant shows the first signs of bolting, as the leaves become bitter afterwards. The harvest can be followed by thorough watering to help new shoots develop well.

Spinach can withstand temperatures as low as -6°C, so it’s possible to continue harvesting it during winter in mild regions.

To keep

Spinach stays fresh for two days in the fridge, but not beyond as it tends to become limp. It’s always best to eat it within a few hours of harvesting. However, you can freeze it after blanching for 30 seconds in boiling salted water, then draining before placing it in the freezer.

After cooking, spinach should be eaten quickly, ideally within 24 hours. As mentioned earlier, spinach acts like a “nitrate pump” – while this trait is very useful in the vegetable garden, it’s far less desirable on your plate! After cooking, nitrates gradually convert into nitrites. These nitrites are toxic compounds for the human body. In high doses, they inhibit cellular respiration! It’s therefore best to consume them soon after the first cooking.

Usage

Traditionally poorly prepared in school canteens, spinach is undoubtedly the vegetable most dreaded by children. Yet it is a tasty culinary herb that can be prepared in countless ways: raw in spring salads, in Japanese tempura, Lebanese fatayer, Indian recipes, or quickly stir-fried in a wok, or even in savoury tarts with small pieces of goat’s cheese or salmon.

Young leaves are excellent when eaten raw

The Health Benefits of Spinach

As we saw in the “storing spinach” section, it’s best to eat spinach within 24 hours of cooking. Apart from this recommendation, spinach has many health benefits! It’s low in calories and:

• rich in minerals, vitamins, fibre, antioxidants and particularly in lipoic acid, an anti-sugar storage molecule,
• good for eye protection thanks to its richness in lutein,
• very rich in vitamin B9, an essential vitamin during pregnancy for the proper development of the foetus, it’s also an anti-depression vitamin!

Did you know?

Popeye long praised the iron-rich qualities of spinach – while it does contain iron, the amounts aren’t phenomenal. This is actually a misconception for which our famous sailor with oversized forearms isn’t to blame at all! We owe this century-old myth to a simple typing error!

In 1870, chemist E. von Wolf was tasked with measuring the nutritional values of various foods. He measured the iron content in spinach and passed his results to his secretary to transcribe neatly. She recorded 27mg per 100g of spinach instead of 2.7mg – ten times more. It wasn’t until 1981 that this error was discovered!