How to grow green onions: Quick tips for a continuous harvest
Green onion is a common household vegetable used for its mild flavored bulbs and green shoots. It is commonly named scallions or spring onions. It is categorized as bunching onions and botanically known as Allium fistulosum.
Green onion belongs to the savory members of the family Amaryllidaceae, which includes many other common vegetables like garlic, leeks, chives, shallots, etc. Onions are also harvested as green onions before the complete development of the bulb.
According to many archeologists and botanists, green onion originated in Central Asia, with ancient traces of cultivation and production in Iran and Pakistan. This vegetable was a common staple of the prehistoric diet, and it was cultivated in Chinese gardens as early as 5000 BCE. Egyptians cultivated green onions back to 3500 BCE. Ancient Romans and Greeks also widely adopted Green onions in their diets. They also introduced their cultivation techniques throughout Europe and the Mediterranean.
Green onions are cultivated for their edible leafy top and white stalk. They are loved for their mild onion flavor and fresh green leaves. The simple cultivation process has made green onions one of the most grown vegetables. Due to their flavor, aroma, and versatility, green onions are used globally in countless cuisines and dishes. They have diverse culinary uses in soups, salads, sauces, dips, and other dishes. Green onions are a perfect choice for flavoring and garnishing meals.
Growcycle provides high-quality tools and resources for cultivating green onions in various environments. They offer a thorough range of solutions, including modern farming tools, fertilizers, pest control techniques, and customized options for gardeners.
With their expert guidance and high-quality products, Growcycle fulfills all the needs of beginner and commercial growers. Anyone can achieve a successful green onion harvest, enriching their kitchens with nutritious, fresh green onions.
Botanical Description
Green onions (Allium fistulosum) are represented by their underdeveloped bulbs. The stem forms bulbous structures known as pseudo bulbs, which store water and nutrients. The plant features long, hollow, and linear green leaves that rise from the bulb's top. These leaves can grow up to 20-25 inches and are important for photosynthesis.
Green onions have a simple, fibrous root system that spreads horizontally beneath the soil’s surface, letting the plant absorb water and nutrients. The stem is the central part of the plant, forming a pseudo bulb to support leaves and roots. Because of their edible bulbs and leaves, green onions are perennial herbaceous plants sometimes treated as annuals.
If not harvested, the green onion plant produces a tall flower stalk that can grow up to 36 inches tall. At the top of this stalk, small star-shaped white or light purple flowers appear with umbel arrangements. These flowers ultimately form tiny dark brown or black seeds, which can be harvested for future planting.
Nutritional Benefits
Green onions contain vital nutrients and offer considerable health benefits when used daily. Growing green onions at home provides a fresh, flavorful yield rich in beneficial compounds. A 100-gram serving of green onions contains approximately 40 calories, 1.1 grams of protein, 0.1 grams of fat, 1.7 grams of fiber, and 9.3 grams of carbohydrates.
Green onions are an outstanding source of vitamin C, delivering around 12% of the RDI per 100 grams. Vitamin C promotes immune health, keeps skin healthy, and is a powerful antioxidant. They also retain small amounts of vitamin B6, which assists in brain function and the formation of red blood cells. Folate found in green onions supports cell growth and proper DNA synthesis.
Green onions can provide a significant amount of potassium (K), contributing approximately 4% of the RDI. Potassium is crucial in maintaining healthy cardiac function and handling blood pressure. Green onions also contain trace amounts of calcium (Ca), which supports bone health, and magnesium (Mg), which is important for nerve and muscle function.
Green onions are abundant in antioxidants like quercetin and sulfur compounds. Quercetin is particularly documented for its role in lowering blood pressure and heart health. The sulfur compounds in green onions also contribute to their typical pungent flavor and are known for promoting healthy cholesterol levels.
Types of Green Onions
Green onions come in different sizes, shapes, and flavors. The common green onion types are:
- Yellow green onions are ideal for cooking because of their balanced flavor.
- Red green onions are often used raw for garnishing and salad because of their vibrant color and milder to sweeter taste.
- White green onions are generally used in Mexican and southwestern cuisines because of their milder taste.
- Shallots are small and delicate green onions. They are used for a mild, sweet flavor.
- Green onions or Scallions are harvested early, with edible green leaves and mini white bulbs.
How to Grow Green Onions
Green onions are a basic need in almost every kitchen and dish. Growing green onions at home is a rewarding experience and easier than people think. Follow the best practices throughout the growing process for a successful yield.
1. Choosing the Right Green Onion Type
Green onions are typically divided into long-day, short-day, and mid-day varieties. It suggests the amount of daylight they need to develop green onion bulbs. Long-day green onions are best grown in hot climates like northern regions; they need 14-16 hours of daylight for proper growth. Long-day varieties include White Spanish green onion, Red Wing green onion, etc.
Short-day green onions are best grown in southern climates, requiring 10-12 hours of daylight. Short-day varieties include Sweet Red, Taxes Sweet White, etc. Mid-day or day-neutral green onions require 10-12 hours of light, but they produce nice bulbs regardless of region or climate. Selecting the right variety according to the location ensures a high probability of successful cultivation.
2. Methods for Green Onion Cultivation
Green onions can be produced from seeds, sets (small, immature green onions), or transplants. The time of planting depends on the method and local climate.
Seeds
Green onion seeds take longer to mature, so they usually start indoors in the late winter, about 8-10 weeks before the last frost. Seeds take the longest to grow but allow for a wider range of varieties. The total duration of the crop from sowing to harvest can take from 100 to 175 days (about 3 to 6 months), depending on the variety. These plants need 3 to 4 months to fully develop bulbs.
Sets
It is easy to grow green onion sets because they are partially grown green onions. Sets are sowed directly in the ground in early spring. They mature faster than seeds but offer fewer varieties. They significantly reduce the growing period within 60 to 100 days after planting.
Transplants
Transplants are young green onion plants grown from seeds in greenhouses, indoors, or purchased from nurseries. They are usually 6 to 10 weeks old and grow shorter than seeds. Like sets, they are planted in early spring and mature quickly. Green onions need about 60 to 120 days to mature.
3. Preparing the Soil
Green onions flourish in well-drained, loose soil enriched with organic matter. They need a slightly acidic to neutral pH between 6.0 and 7.0. A well-prepared soil can guarantee a successful yield.
Use a soil test kit to inspect the soil's pH levels. If the soil is more acidic, use lime to raise the pH. For alkaline soil, use sulfur to lower the pH. 6.0 to 7.0 is the suitable pH range for growing green onions.
Add well-rotted manure and compost to enhance the soil's nutrient quality and drainage. Green onions require loose soil for proper bulb formation. A garden fork or tiller breaks up any clumps and loosens the soil to aerate it. Green onions don’t compete well with weeds, so keep the area weed-free before planting.
4. Make Green Onions Bed
Seed sowing requirements vary from planting sets to transplants. The first thing to consider while planting green onions are the quality of seeds and the health of sets. A healthy and disease-free start leads to a fresh and flavorful harvest.
Seeds Sowing
Seed sowing starts indoors in pots, small containers, or seed trays. The appropriate time to plant seeds is about 8-10 weeks before the last frost. Stuff the pot or container with a seed starting mix and put the seeds ¼ inch deep in the soil. Place seed trays near a sunny window or under glow lights because green onion seeds need plenty of light to germinate.
Water spray the soil to keep it evenly moist. About a week before transplanting outside, gradually introduce the seedlings to the outdoor environment. This helps seedlings easily accommodate in outdoor areas and grow promptly.
Planting Sets
Sets are small, immature green onion seedlings directly planted in the garden soil or container. Before planting the sets, prepare the soil well with compost and fertilizer. Tilling the ground with a garden fork or tiller to completely lose the soil makes it airy and fertile for abundant green onion growth. Green onion sets are planted 1-2 inches deep in the ground with the pointed end facing up. Plant sets 4 inches apart in rows 12-18 inches apart. After that, water the ground immediately to help them establish.
Transplants
Before planting the transplants, prepare the soil and make holes about 1 inch deep and 4 inches apart, spacing the rows 12-18 inches apart. After planting the transplants in the holes, gently put and press the soil around the plant base and sufficiently water it.
5. Harvesting
Harvesting green onions is simple and can be done multiple times throughout the growing season. Green onions are usually ready to harvest about 6-8 weeks after planting. Look for leaves about 6-8 inches tall, indicating they are mature enough for harvesting.
To harvest, use scissors or a knife to cut the green onions about an inch above the soil. This allows the plant to regrow for another harvest. If growers prefer to harvest the entire plant, gently pull it out of the soil, holding the base to avoid breaking the leaves.
Growers can also regrow green onions from scraps. They need to place the white root ends in a glass of water, change the water every few days, and keep the glass in a sunny spot. New green shoots will start to grow within a week.
After harvesting, it’s necessary to rinse the green onions and store them in the refrigerator. To maintain freshness, people can keep them in a plastic bag or a container with a bit of water.
Growing Green Onions in Containers
Growing green onions in containers is a good choice if growers have little garden space. It's important to pick the right container. Even though green onions have shallow roots, they need a deep pot to grow bulbs properly. Choose a pot that's 10-12 inches deep. The pot should be wide enough to plant the green onions 4-5 inches apart.
Fill the pot with high-quality potting mix and plant the green onion sets or transplants like in a garden. Use plastic, clay, or wood containers, as long as they have drainage holes to prevent water from collecting in the soil. Place the container on a patio, balcony, or indoors near a window with enough sunlight or under grow lights.
Tips to Care Green Onions
Green onions are fairly low-maintenance plants but need constant supervision and care for a healthy crop. After the plantation, keeping moisture and fertilizer in the ground is mandatory.
Watering
Proper moisture keeps green onion plants hydrated and helps them grow well. The average water need of a green onion plant is approximately 1 inch underground per week. Watering in the early morning maintains moisture throughout the day while allowing leaves to dry out during the day. Dry leaves remove fungal infections and absorb enough sunlight to form nice bulbs. Overwatering leads to root rotting and plant death.
Fertilizing
Green onions are heavy feeders and require regular fertilization. Use a good fertilizer every 2-3 weeks during the growing season. Leaf yellowing indicates nitrogen deficiency. In the case of yellow leaves, green onions need more nitrogen-rich fertilizer.
Weeding
Green onions can not compete with weeds for nutrients and sunlight, so it is necessary to keep green onion beds free from weeds. For excessive weeds, use manual weed pulling or a hoe. Be careful while weeding to avoid disturbing green onion plants with shallow roots.
Mulching
Mulching helps preserve water content, repress weeds, and control soil temperature. To retain moisture and keep weeds at bay, apply a thin layer of straw, grass clippings, or compost around the green onions.
Pest and Disease Control
Green onions are less susceptible to pests and diseases due to their strong, spicy aroma, but they can still get attacked by pests and diseases. Here are some common issues with the simplest known solutions for green onion plants.
- Maggots: These small larvae feed on the bulbs, causing wilting. Floating row covers save plants from adult flies laying eggs.
- Thrips: These minute insects can cause harm to the leaves. Handle them with insecticidal soap or neem oil.
- Fungal Diseases: Diseases like downy mildew and green onion smut can be problematic, especially in wet conditions. Good air circulation should be provided, and overhead watering should be avoided to prevent these issues.
Regularly examine the plants for symptoms of pests or disease, and take action early to avoid serious damage.
Best Plants to Grow with Green Onions
Companion planting with green onions can help the garden to improve growth, repelling pests, and boosting flavor. Here are some of the best plants to grow alongside green onions:
- Carrots: Green onions help repel carrot flies, while carrots improve soil health without competing for space.
- Lettuce: Green onions can keep pests away from lettuce, and both plants grow well in the same soil conditions.
- Beets: Beets benefit from green onions’ pest-repelling properties and don’t compete for the same nutrients.
- Tomatoes: Green onions can protect tomatoes from harmful pests such as aphids and caterpillars.
- Herbs (Dill, Parsley, and Mint): These herbs attract beneficial insects while deterring pests that could harm green onions.
Plants to Avoid Growing with Green Onions
Some plants should not be grown with green onions. Here are some of them:
- Beans and Peas: Both beans and peas grow stunted when planted near green onions due to chemical interactions inhibiting their root development.
- Asparagus: Green onions compete with asparagus for nutrients and space, negatively affecting the asparagus's deep root system.
- Sage: Sage's strong oils can inhibit green onion growth, making it an unsuitable companion.
- Other Alliums: Garlic, leeks, and shallots can attract shared pests and deplete similar nutrients, leading to disease and nutrient competition.
- Brassicas: Broccoli, cabbage, and cauliflower are heavy feeders which compete with green onions for nutrients.
FAQs
How long does it take to produce green onions from seed to harvest?
Green onions generally take 90 to 120 days to mature from seeds, depending on the type and cultivating conditions. Sets or transplants may reduce the time to 60 to 80 days.
What type of soil is best for growing green onions?
Green onions like well-drained, loose, and nutrient-filled soil with a pH between 6.0 and 7.0. Adding compost or organic matter enhances soil quality and drainage.
Can green onions grow in containers?
Yes, green onions grow well in containers. Select pots that are at least 10-12 inches deep, provide good drainage, and fill them with high-quality potting mix.
The Bottom Line
Growing green onions is an excellent choice for both new and experienced gardeners. They are versatile, easy to cultivate, and can thrive in limited spaces like containers. Growers can enjoy multiple harvests throughout the growing season with minimal care and the right conditions. Green onions add a fresh, flavorful touch to countless dishes, whether used as a garnish, ingredient, or even regrown from scraps. By incorporating these hardy plants into the gardening routine, growers will always have a supply of fresh, homegrown green onions at their fingertips.
Growcycle offers the best range of gardening tools and products for green onion cultivation. It provides top-notch quality, durability, and aesthetic appeal for successful indoor and outdoor gardening.
Disclaimer: This material is for informational purposes only and should not be relied on for legal, medical, financial, or other professional advice.
About the Author
Victor Miller 
Environmental Journalist Focused on Sustainable Agriculture
Victor Miller is an environmental journalist at Growcycle, where he covers the latest news, trends, and innovations in sustainable agriculture. He has a deep passion for storytelling that emphasizes ecological balance and responsible farming practices.
Before joining Growcycle, Victor worked for several agricultural and environmental publications, reporting on significant environmental issues and interviewing key figures in the sustainability sector. His work has been featured in various industry journals and online platforms.
