Spring Onions - Key Growing Information

Spring onions, also known as green onions or scallions, are a versatile and easy-to-grow addition to any home garden. Whether you’re a novice gardener or a seasoned pro, understanding the nuances of growing spring onions can help you produce a bountiful harvest with the perfect balance of green and white. This guide will delve into the methods for achieving optimal color in your spring onions, recommend the best varieties for year-round sowing, and cover various growing methods.

Quick Jump:

• Variety Selection
• Green Vs White Parts
• Spacing of Spring Onions
• Watering Techniques
• Growing from Seed
• Sowing in trays & pots
• Sowing in modules & trays
• Crop Culture
• Spring onion packet size
• Harvesting

Understanding the Basics: Green vs. White Spring Onions

The color of your spring onions—whether they lean more towards green or white—depends on a few key factors: variety, planting method, spacing, and watering.

Variety Selection

Different varieties of spring onions are predisposed to produce varying amounts of green and white parts. Here are some popular varieties and their characteristics:

'White Lisbon': A classic variety known for its crisp white bulbs and tender green tops. It’s versatile and can be grown almost year-round.

'Evergreen Hardy White': True to its name, this variety remains hardy through colder months and produces strong white bulbs.

'North Holland': While primarily a red onion, it can be harvested early as a spring onion with vibrant green tops and reddish bulbs.

Planting Methods: Bunching vs. Non-Bunching

How you plant your spring onions can influence the proportion of green to white in your harvest.

• Bunching: Planting spring onions closely together (about 1 inch apart) encourages them to compete for light and space, which can result in longer white stems as they grow taller to reach light.
• Non-Bunching: Spacing spring onions further apart (2-3 inches) allows them more room to grow and typically results in more extensive green tops because the plants are not competing as intensely for resources.

Culinary Uses: White vs. Green Parts

The color of your spring onions isn't just a matter of aesthetics—it can also influence their culinary uses.

• White Parts: The white part of the spring onion has a more intense, onion-like flavor. It's often used in cooking to add depth and richness to dishes. These can be finely chopped and sautéed as the base for soups, stews, and stir-fries, or used raw in salads and salsas for a punchy flavor.
• Green Parts: The green tops are milder and more delicate in flavor. They are perfect for use as a garnish or for adding a fresh, subtle onion taste to dishes. The greens can be chopped and sprinkled over baked potatoes, salads, soups, and other finished dishes to provide a burst of color and a hint of flavor without overpowering the other ingredients.

Spacing and It's Impact on Spring Onions

Spacing is crucial for determining the overall size and color balance of your spring onions. Here’s a breakdown of how different spacing affects growth:

• Close Spacing (1 inch apart): Leads to elongated white stems due to the competition for light. This method is ideal if you prefer more white in your spring onions.
• Wider Spacing (2-3 inches apart): Allows for fuller green tops as each plant has more access to sunlight and nutrients. This is best if you want a greater proportion of green.

Watering Techniques

Watering is another critical factor in the development of spring onions:

• Consistent Watering: Keeping the soil consistently moist but not waterlogged encourages uniform growth. Well-watered plants tend to have more robust green tops.
• Deep Watering: Watering deeply and less frequently promotes root growth, which can support longer white stems.

What is Deep Watering?

Deep watering involves applying water slowly and thoroughly so that it penetrates deep into the soil. Here’s a more detailed look at how to practice deep watering:

• Frequency: Instead of watering a little bit every day, water your spring onions less frequently but more thoroughly. This encourages roots to grow deeper into the soil as they search for moisture, resulting in stronger, more resilient plants.
• Technique: Water the soil until it is moist to a depth of at least 6 inches. You can check the depth by inserting a spade or a moisture meter into the soil. If the top few inches of soil dry out between watering sessions, that’s okay, as long as the deeper soil remains moist.
• Timing: Early morning is the best time to water, as this allows any excess moisture on the leaves to evaporate during the day, reducing the risk of fungal diseases.
• Tools: Use soaker hoses or drip irrigation systems to deliver water directly to the base of the plants, minimizing evaporation and ensuring that water reaches deep into the soil. If using a watering can or hose, apply water slowly to give it time to seep in rather than run off.

Growing Spring Onions from Seed

Starting spring onions from seed is a straightforward process that allows you to grow a large number of plants economically.

• Sowing: Sow seeds directly in the soil or in seed trays, spacing them about 1 inch apart.
• Depth: Cover seeds lightly with soil, about 1/4 inch deep.
• Watering: Keep the soil consistently moist until the seeds germinate, which usually takes 7-14 days.
• Thinning: Once seedlings are established, thin them to 2-3 inches apart to allow ample space for growth.

Growing Spring Onions in Pots and Containers

Spring onions are ideal for container gardening, making them perfect for small spaces or urban gardens.

• Container Selection: Choose a pot that is at least 6 inches deep and has good drainage.
• Soil: Use a high-quality potting mix enriched with compost.
• Planting: Sow seeds or plant seedlings at the same depth and spacing as you would in the ground.
• Care: Water regularly and ensure the container receives at least 6 hours of sunlight daily.

Growing Spring Onions in Seed Trays and Modules

Starting spring onions in seed trays or modules can give you a head start on the growing season.

• Filling Trays: Fill seed trays or modules with a seed-starting mix.
• Sowing: Sow seeds thinly in trays or one or two seeds per module.
• Germination: Place trays in a warm, bright location. Keep the soil moist but not waterlogged.
• Transplanting: When seedlings are 4-6 inches tall, transplant them into the garden or larger containers, spacing them appropriately.

Crop Culture

Traditional sowing times vary for bunching onions (spring or salad onions). Spring is the recommended sowing time, with August quickly following for a winter and early spring harvest. As the UK weather has gotten milder over recent years, you can sow and grow spring onions all year round. Although germination during winter months (October - February) takes a little longer due to light levels, you can still maintain a healthy crop.

Hardy varieties will survive the winter if you wish to grow them outdoors; well-draining soil is recommended. However, we suggest sowing and growing spring onions under cover during the winter months.

Recommended soil acidity: 6.2 - 6.8 pH.

Planting

Sow directly (however, you can transplant them if you prefer to start in trays, handling them as you would any other onion or leek seedling). Sow 5-6 seeds per sowing, keeping a good 2-3 inches of space between the next sowing. Thin by taking an early harvest, also known as green onions. This method allows you to oversow in a specific area and start harvesting much sooner. By naturally thinning the younger onions and eating them, you make room for the bulb to grow and swell to the larger spring onion.

Hilling

During the growing process, hill the soil (as you would with potatoes) 2-3 times during the growth cycle. This forces the leaves higher up the plant, resulting in extra-long stalks and a much greater edible portion or whiter onion.

This method is recommended if you have directly sown your seeds. Transplanting onions eliminates this issue.

Harvesting

Loosen with a fork and lift from the ground. Pulling the plant directly may result in the bulb detaching from the stalk.

Packet Size

Allium cepa 'White Lisbon'

'White Lisbon' is a widely grown variety of spring onion that is favored for its reliability and excellent flavor.

• Characteristics: Produces crisp white bulbs and tender green tops.
• Sowing Time: Can be sown from early spring to late summer for continuous harvest.
• Growing Conditions: Thrives in well-drained soil with plenty of organic matter.
• Harvesting: Ready to harvest in about 8-12 weeks from sowing.

Final Tips for a Successful Harvest

• Soil Preparation: Spring onions prefer well-drained, fertile soil. Adding compost can enhance soil structure and nutrient content.
• Thinning: If you’ve sown seeds densely, thin the seedlings to your desired spacing to ensure healthy growth.
• Mulching: Mulch around your spring onions to retain moisture and suppress weeds.
• Harvesting: Harvest when the onions reach your desired size. For a continuous harvest, sow new seeds every few weeks.

By understanding and manipulating these factors, you can tailor your spring onion crop to achieve the perfect balance of green and white.