Growing onions: Easy steps to plant, care, and harvest onions at home

Onion is a staple vegetable used in many cuisines. It is scientifically known as Allium cepa and belongs to the genus Allium, which also includes garlic. The word “onion” is derived from the Latin word “Unionem,” which means “pearl.” In old French, it was called “Oignon,” and in Middle English, “Onyoun,” meaning the sense of unity. This vegetable was initially grown in Central Asia, Iran, and West Pakistan for food and medicinal purposes. 

Egyptians, Romans, and Greeks were the first cultivators of onion, and it gained popularity even in their religious rituals as a sign of strength and endurance. Onions are believed to have properties to treat mouth sores, headaches, heart diseases, and hair growth issues. 

This staple food was famous in prehistoric diets because of its easy availability, convenient storage, less perishability compared to other foods, fast dryness, and compatibility with multiple types of soils. Egyptians placed the onions in pharaohs' tombs, believing they would keep eternity like its concentric layers. 

Today, it is a major cash crop for farmers because of its extensive use and high market demand worldwide. Onion plantation helps improve soil health while decreasing soil compaction, pest resistance, and disease control and is the best choice as a rotational crop. It has a long shelf life, which decreases the risk of stock shortage, maintaining a steady supply throughout the year. Their plantation in home gardens is recommended to get fresh, cost-effective, and flavorful onions. 

Growcycle helps onion growers with the best toppings, soil mixes, and customized fertilizers to boost onion yield and elevate quality. They ensure the best PH, nutrient management, organic matter, and crop rotation techniques for better onion growth. They guide how frequently one should irrigate the onion crop and which method is efficient for optimal water use and preventing bulb rot-like issues. They provide extensive knowledge about variety selection according to the climate, individual plant’s nutritional needs, and garden preferences.

Onion Morphology

Before starting an onion plantation, it is mandatory to know the plant’s botanical structure, including its root system, bulbs, leaves, stems, flowers, and seeds. 

Understanding this helps the grower implement the growth techniques according to the function of the plant’s organs. 

• Root system

The onion has a fibrous but shallow root system consisting of thin, horizontally spread roots extended up to 12 inches. These roots absorb water and nutrients from the soil and send them to the last inch of leaves. However, as the root system is not well developed, the onion plant is always susceptible to extreme weather conditions, and in droughts or floods, the plant will die. 

• Bulb

Bulbs are the plant base, which is swollen in nature and creates concentric layers overlapping each other. The bulbs consist of fleshy leaves, a rich source of nutrients that retain water for extensive weather conditions. Bulb size and color may vary depending on the variety, but generally, they range from yellow to white and red. 

• Leaves

The onion leaves are usually bluish-green in color, cylindrical in shape, internally hollow, and alternately placed. From the bulb base, they create a flattened and fan-shaped appearance. The major function of these leaves is photosynthesis, which means preparing energy for plant growth by using sunlight. 

• Stem and Flowers

Onion stems, or basal plates, are usually compressed and flattened. In the second year of growth, the plant produces hollow and long cylindrical flowering stalks, which grow spherical plant clusters or umbels.

The onion flowers are usually small, greenish-white in color, with six tepals, and hermaphrodite in nature. They contain both male and female organs. The male organs are called stamens, while the female organs are called pistils. 

• Seeds

Pollination can occur through insects as cross-pollination or directly as self-pollination, resulting in tiny, black seeds being encapsulated into cover. Onions can be grown in multiple ways, but the most common are through seeds, bulbs, or offsets.

Onion Nutritional Value

Onion is a nutrient-rich food containing quercetin as a major ingredient, which helps lower blood pressure and reduce body inflammation. It also provides prebiotic fibers to prevent gut health issues, facilitating the growth of good gut bacteria. It improves blood vessel functions and reduces body cholesterol levels, improving heart health and decreasing the chances of heart attacks and nervous breakdown. Besides these, a 100 gram raw onion contains:

• Calories: 40 kcal
• Water: 89%
• Protein: 1.1 grams
• Carbohydrates: 9.3 grams
• Fat: 0.1 grams

Apart from these macronutrients, onion contains vitamins C, B6, and B9, known as folate, potassium, and manganese. Similarly, it also provides a minor calcium, iron, magnesium, phosphorus, zinc, copper, and selenium ratio. 

Types of Onions (Based on Day Length)

Based on the growth pattern, growing zone, planting time, and daylight requirements, onions are divided into three major types: long-day, short-day, and day-neutral onions. A quick overview is given below:

• Long Day Onions

This onion requires at least 14 to 16 hours of daylight; without such extensive light, it can’t initiate bulbs or initiate them poorly. That’s why they are primarily grown in northern climates, which usually have long summer days and extensive daylight. These onions are mostly grown in late winter or early spring, and the most common examples include Italian, walla walla, and red zeppelin. 

• Short Day Onions

They require 10 to 12 hours of daylight, meaning the ideal regions for their growth are those with shorter days. Their best planting season is fall or winter, while the best harvesting season is early spring. The most common examples include yellow Granex, super sweet, and Granex. 

• Day Neutral Onions

They are also known as intermediate-day onions and initiate bulb formation regardless of the number of daylight hours and weather conditions. So, they can be grown anywhere, maintaining some essential plant growing conditions. The best seasons for their cultivation are early spring for northern region plant growers and fall for mild winter region growers. The most common examples include superstar, candy, and red candy apples.

Varieties of Onion

There is a wide variety of onions worldwide; some are grown for raw resting, pickling, and roasting, while others are used in cooking. Each variety varies in color, nutritional value, suitable growing environment, and taste. Some of the top variates are:

• Yellow Onions: Common, strong-tasting, used in most cooking.
• Red Onions: Purple-red, crunchy, often eaten raw.
• White Onions: Sharp taste, juicy, popular in Mexican food.
• Sweet Onions: Mild, sugary, good in salads.
• Pearl Onions: Very small, crunchy, often pickled.
• Cocktail Onions: Pickled, spiced, used in drinks.
• Leeks: Long, mild-tasting, looks like giant green onions.
• Spanish Onions: Large, mild, suitable for cooking.
• Torpedo Onions: Long shape, sweet, great grilled.
• Shallots: Small, taste like mild garlic and onion mix.
• Cipollini Onions: Flat, sweet when cooked, good for roasting.
• Scallions (Spring Onions): Long green tops, mild, used fresh.
• Ramps: Wild onions with a garlic-like solid taste.
• Welsh Onions: They look like big scallions, which are common in Asian cooking.

Growing Onions: Easy Steps to Plant, Care, and Harvest

Onion cultivation is a straightforward process. Creating a hole in the soil shouldn't be a significant challenge for an individual. Humble bulbs can transform into garden giants if proper techniques and steps are followed.

The growing method has two significant sources: bulbs and seeds, each with specific tips and methods but with the same production results. Here is a detailed process of growing this efficient and rewarding plant:

1. Preparation for Planting

Preparation involves considering the availability of components and tools a grower can use during activity and early soil preparation. These steps are like executing tasks that create an adequate environment for tiny roots to flourish.

• Timing

The chosen type and growing environment of the grower will help one decide the ideal timing. Still, early spring days are more workable for growing onions, whether in increasing gardens or in-ground gardens. Areas that have long summer and short winter seasons can plant the onion seeds in late winter to spring start, whereas late summer days are ideal for planting the seeds in regions with Mediterranean climates.

• Ideal Location

The key to success in onion planting is the selection of ideal soil. The favorable nutrients can be absorbed from a location with a balanced pH and moisture level to fulfill the sunlight requirements The onion plant thrives best in sunny locations, so a sunny spot with a minimum of 6-8 hours of sunlight can be considered for sowing. The soil of the selected spot should be well-drained, rich in nutrients, acidic to neutral pH, and sandy loam in texture.

• Soil Preparation

Changes to soil conditions are possible based on current conditions. However, before incorporating any more mixture, the pH test is used to identify appropriate substances to include into the soil. This test can be performed through various commercial kits; soil 4-6 inches deep is best where plant roots must grow. Similarly, adding organic matter or compost and frequent tilling can improve nutrient absorption.

2. Planting Onions

The process of planting onion is as layered as the bulbs themselves, surrounded by various gardening techniques.

• Choosing Planting Method

Planting through bulbs is straightforward for beginners as the bulbs are easy to handle and take less time to grow, whereas seeds require extra germination and root sprouting. The seeds need to be sown in a seed tray or pot filled with seed starting mix for seed planting.

After germination, these seeds are transplanted into growing beds or garden soil. The onion sets can be transplanted directly into the soil without soaking them in water, ensuring their tips are above the surface. 

• Planting Guide

The seed plantation should be 1-4 inches deep with a 1-inch gap between each seed, and the pot or container must be in a sunny location where 12-14 hours of sunlight can reach.

The sets should have 1-2 inches of space with 12-18 inches rows apart. The sets are not planted deeply but require a thin soil layer for mature development. After planting, the seeds and sets need moist soil, but they should not be soggy to create fungal diseases. 

• Companion Planting with Onions

Carrots, Lettuce, Beets, Cauliflower, Cabbage, and Broccoli are some companion plants that can grow healthy near onion plantings because pests deterred by onions help to develop them safely. The carrot fly does not attack plants if cultivated near onions; their nutritional competition is effective for both plants.

Lettuce and onions require the same sunlight and soil requirements, so their combination is a complementary task for farmers. The cabbage family grows healthy near onions by staying safe from aphids and worm attacks.

3. Caring for Growing Onions

Care for growing bulbs is a necessary step in planting to ensure a healthy harvest. Here are some essential key points to follow for it: 

• Watering

Both the frequency and quantity of water are influenced by weather conditions and regional climate. However, during dry and hot weather, young growing plants require regularly moist soil that is not waterlogged.

During the initial growth phase, it is recommended to keep a watering schedule of every 2-3 days. However, it is important to avoid allowing the water to accumulate on the surface. Minimal moisture content is sufficient to provide the necessary needs.

Tubes and emitters can supply sufficient water for each plant but prove costly for commercial crops. Sprinkling with pipe or surface irrigation can also be considered for more extensive plantations.

• Fertilizing

Phosphorus rich or balanced fertilizers can be used to promote healthy growth before planting. The amount of fertilization needed continues according to the soil type and plant requirements. After growing the plants, growers can apply 4-6 long, nitrogen-rich fertilizers. 

Compost, manure, or fish emulsion can be used as organic compounds. After bulb formation, potassium-rich fertilizer helps produce mature and healthy bulbs, but excessive use of fertilized material should be avoided in the last period.

• Weed control

Organic and inorganic mulches can prevent weed growth and retain the soil moisture level.  Straw, shredded leaves, and grass clipping are better options for organic mulches; black plastic or landscape fabric is considerably used as inorganic mulches.

Applying mulch should be away from the plant’s stem and 2-3 inches thick to keep the soil warm and protected from weeds. Hand weeding is an easy and cost-effective way to eradicate small weeds; it requires gentle handling because the risk of onion root damage is obvious.

• Pest and Disease Management

Thrips and onion maggots are common pests that stop plant growth, insecticidal soap or neem oil, and beneficial insects like predatory thrips or lacewings can be used to control attacks organically. Floating row covers and incorporating beneficial nematodes are also helpful in pest control.

The application of pesticides containing pyrethrin or spinosad can effectively manage thrips, whereas insecticides such as diazinon or permethrin can effectively control maggots. Downy Mildew causes yellow or white molds of bulbs, and Neck Rot affects the onion neck with rotted bulbs.

Using copper-based fungicides or potassium bicarbonate and crop rotation with proper sanitation planting can reduce disease attacks. Fungicides containing thiabendazole, metalaxyl, or Mefenoxam are the chemical solutions to control disease.

4. Monitoring Onion Growth

The growth process starts with seed germination, which results in seedlings. Then, leaf development occurs, and vegetative growth begins when under-soil bulbs mature. Proper monitoring of each stage helps tackle the issues without delay and provides timely harvesting of crops.

If the leaves show a rigid and vertical growth pattern without any changes in color, the plant is in a state of optimal health. The bulbs’ health can be determined by their size, which should be well-developed and rot-free. The slow and steady growth with the developing roots indicates that the plant is eating adequate nutrition.

5. Harvesting Onions

The harvest time starts after mature bulb formation, and the following considerations are necessary while collecting the planting reward:

• Determining the Right Time to Harvest

The onions become ready for harvesting when the tops fall over about two-thirds and turn brown, the onion necks start getting dry, and the bulb skin becomes papery. The exact duration between planting and harvesting depends on the climate and selected seed variety, but 100-120 days is the general growth period of onion bulbs.   

• Proper Harvesting Techniques

The garden fork helps to loosen the soil before digging out the bulbs. To minimize resistance during final harvesting, it is recommended to place the bulb 4-5 inches away from the plant base. Once the bulbs have lost their roots, they can be securely removed from the soil. 

A fork can safely remove the onions, but hands are the quickest way to wiggle and lift them without damaging the bulbs.

• Curing Onions for Storage

The onions can be stored for yearly consumption; after harvesting, they need to be cured for safe storage. Spreading them in a shaded and well-ventilated space in a single layer for 2-3 days helps to reduce moisture. Trimming tops from 1 inch of the bulb and thoroughly root cutting helps prevent bacterial growth or fungus infection during storage.

6. Storing Onions

The following tips are useful to use and store the cured onion:

• Best Storage Practices

Cured onions should be stored in a cool, dry, ventilated place at a lower humidity and temperature of 32°F to 40°F. Mesh bags, woven baskets, or slotted crates are beneficial for storing onions with better air circulation. Plastic bags should be avoided for storage because they can create moisture and rot the onions.

• Shelf Life

The shelf life depends on the onion variety because yellow and red types can be stored for 6-8 months due to their lower moisture qualities. Vidalia or Walla Walla varieties can be spoiled after 2-3 months for the higher water content. However, early signs of spoilage can save the farmer from significant loss, and the onions can be used before deterioration.

• Culinary Uses

Homegrown onions can be used for versatile culinary experiences; for example, their fresh taste can boost the flavor of salads and sandwiches. On the other hand, caramelized onions in soups and stews have rich health benefits. Fresh and organically planted onions in the home require fewer chemical treatments, so their nutritional value is maintained during meals.

Useful Tips For Growth

• If a plant suffers from a disease, the quickest way to eliminate it is to dissolve aspirin in water and water the plant. 
• Empty egg shells can be used as good biodegradable starters. The plant is directly grown into eggshells filled with soil; even after transplanting, it still doesn’t need to remove the eggshells. They decompose automatically, providing the soil with calcium.
• A clean diaper can be used around the roots to retain plant moisture. Similarly, burying banana peels around the roots gives the plant an immense supply of calcium, phosphorus, and potassium necessary for fast growth. 
• A mixture of one-part milk and two-part water is an excellent treatment for powdery mildew and other fungi because of the protein in the milk. 
• According to the lunar cycle, gardening plants can improve plant growth because the moon's gravitational pull dramatically affects the water in the soil. 
• Cinnamon is a natural rooting hormone, so dipping plant cuttings into cinnamon powder before planting can prevent fungal infections and boost plant growth.

FAQs

How can I prevent my onions from developing a strong, pungent flavor?

The onion's pungent smell is caused by sulfur compounds absorbed from the soil. Soaking onions in cold water, using vinegar, sprinkling lemon juice, adding salt and washing, and using different cooking methods can easily remove this smell. 

Is it necessary to rotate where I plant onions each year?

It is a rule of thumb that no crop should be produced too long on the same soil because it leads to nutrient deficiency and soil erosion. Similarly, rotating the onion crop at least every three years is necessary. It will help disrupt the pest's life cycle and decrease their prevalence, making the soil healthy and balancing nutrients and pH.  

Is it possible to regrow green onions from kitchen scraps?

Yes, it is possible to regrow the onion from kitchen scraps, but only when at least one inch of white part is attached to the roots. After getting it, it should be placed into a jar, and the roots should be dipped into the water. However, the most important thing is the availability of sunlight. If an adequate water supply and sunlight are maintained, the roots will produce green shoots within a few days.

The Bottom Line

Establishing a good onion plantation requires following a few essential protocols like using high-quality seeds or transplants, maintaining a balanced soil pH, and including a substantial amount of organic matter into the soil.

Fertile soil helps develop strong roots. Make sure to plant onions 4 to 6 inches apart for large bulbs. Use advanced watering methods to keep the soil moist without causing waterlogging to avoid root rot. Balanced fertilizers and proper mulching prevent diseases, pests, and weeds, ensuring a steady nutrient supply. Following these techniques carefully will lead to high yields with minimal resources.

Growcycle offers all the tools and equipment needed to grow onions in any environment. They provide grow lights and supply various nutrients and soils for optimal results. Additionally, they offer greenhouse kits, ready to use planting beds, soil enhancers, and many other products to ensure fast and effective growth. Consulting with Growcycle gives growers useful knowledge, practical tips, and advanced resources to improve their growing process.

Disclaimer: This material is for informational purposes only and should not be relied on for legal, medical, financial, or other professional advice.