Jiromaru Spinach leaves on a white background.
Jiromaru Spinach leaves in a box, sauteed over rice and as a salad arranged on light background.
Jiromaru Spinach leaves with some cooked in bowl with chopsticks on light green background.
Steamed Jiromaru Spinach on a plate with some fresh leaves on pink background.
Jiromaru Spinach with spinach pancakes and fresh leaves on yellow background.
Jiromaru Spinach cooked with rice on bed of fresh leaves.
Jiromaru Spinach leaves on a white background.
Jiromaru Spinach leaves in a box, sauteed over rice and as a salad arranged on light background.
Jiromaru Spinach leaves with some cooked in bowl with chopsticks on light green background.
Steamed Jiromaru Spinach on a plate with some fresh leaves on pink background.
Jiromaru Spinach with spinach pancakes and fresh leaves on yellow background.
Jiromaru Spinach cooked with rice on bed of fresh leaves.

Spinach Seeds,
Jiromaru

42 ReviewsSKU: #SP112Min. seed count: 250
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Description

(Spinacia oleracea). Best flavor in our taste tests! This productive and delicious spinach is a beloved staple in Japan, where the variety originated. The distinctive arrow-shaped leaves are a familiar sight at Japanese markets. It is commonly grown in Inazawa City in Aichi Prefecture, on the Nobi Plain, where it is believed that a western variety of spinach was crossed with a local native type many generations ago.

Growing Tips: Jiromaru spinach prefers full sun to partial shade and grows best in well-drained, fertile soil enriched with organic matter. This spinach is ideal for small spaces and container gardening. Provide ample moisture and protect the plant from summer heat, as that can cause plants to bolt.

Plant Details

Botanical Name
Spinacia oleracea
Life Cycle
Annual
Sun Requirement
6–10 hr.
Days to Germinate
7–14
Days to Maturity
30–40
Planting Depth
½ in.
Plant Spacing
6–8 in.
Ideal Temperature
45–75°F
Frost Hardy
Yes

When to Grow

Jiromaru spinach grows best in cooler weather and should be planted in late winter or early spring, as soon as soil can be worked. The plant grows best in temperatures ranging from 45-75 F. Its cold tolerance allows it to withstand light frosts, making it suitable for extended growing seasons in USDA zones 4-9. If you’re not sure how to find your area's first and last frost dates, consult our blog post 'Our Experts Answer Questions, Share Resources.'

How to Sow and Plant

To plant Jiromaru Spinach, sow the seeds directly into the garden at a depth of 1/2 inch, spacing them 2-4 inches apart in rows that are 12-18 inches apart. After germination, thin the seedlings to 6-8 inches apart to reduce competition and encourage healthy growth. The soil should be well-drained and rich in organic matter. Incorporating compost or a balanced fertilizer before planting will help support robust leaf production.

How to Grow

This variety requires consistent moisture to produce tender, succulent leaves, so regular watering is important. Keep the soil evenly moist but avoid waterlogging. Mulching around the plants helps retain soil moisture and control weeds. Jiromaru spinach prefers cooler temperatures, so during unexpected warm periods, providing partial shade can help maintain leaf quality. Fertilize with a nitrogen-rich fertilizer during the growing season to support lush foliage growth.

How to Save Seeds

  • In spring, plants will grow tall and bloom (or bolt) as soon as the days are longer than 14 hours. Heat also speeds up bolting, since spinach prefers temperatures between 35 and 75 degrees.
  • Commercial spinach seed crops are separated by 5-10 miles. Spinach pollen is so fine that it easily penetrates mesh screening, but is severely restricted by spun polyester fabric.
  • Plants are either male or female. Maintain a ratio of one male to two female plants, though this is hard to determine until the seed stalks have formed. Close plantings in wide beds will provide the greatest chance that the ratio will be hit.
  • Starting at the bottom of the plants, strip off the seeds (using gloves for the prickly type) in an upward motion, letting them fall into a bag.
  • Allow to completely dry and store.
  • They will retain 50% germination for up to 5 years when stored in ideal conditions (cool, dry, and dark).

FAQ

Can Jiromaru spinach be grown in containers?

Yes, it is well-suited for container gardening. Use a pot at least 6-8 inches deep with good drainage, filled with high-quality potting mix. Place the container in a location that receives full sun to partial shade and keep the soil consistently moist.

How long does it take to harvest Jiromaru spinach?

It is a quick-growing variety that is typically ready for harvest within 30-40 days after planting. You can start harvesting baby leaves as early as 20 days after sowing. For a continuous supply, use the cut-and-come-again method, harvesting outer leaves while allowing the inner leaves to continue growing.

What are common pests and diseases affecting Jiromaru spinach?

Common pests include aphids, leaf miners, and slugs, while diseases such as downy mildew can occasionally occur. To manage pests, use organic methods like insecticidal soap or neem oil. Ensure good air circulation around plants and avoid overhead watering to minimize the risk of fungal diseases.

Browse our full range of spinach seeds.

Customer reviews

4 / 5 2 Reviews
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