Organic Fertilizer for Onions & How to Grow Onions for Maximum Yield

Fertilizer for Onions and Growing Tips: How to Grow Onions Successfully

Selecting the right variety for your growing region is important to the success of growing onions. There are short-day, intermediate-day and long-day varieties. Choose the one best suited for your area. For more information on growing zones and the best fertilizer for onions, check out our blog How to Select the Best Onions and Leeks.

Importance of growing onions at home

Growing onions at home is a rewarding experience for any gardener. Understanding how to grow onions starts with planting onion bulbs in well-drained, sandy soil enriched with composted manure or organic fertilizers. 

A soil test helps determine nutrient needs, allowing you to choose the right fertilizer for onions, such as ammonium sulfate or calcium nitrate, for optimal growth. Throughout the season, mulching and applying balanced fertilizers support healthy leafy growth, prevent weeds, and ensure a bountiful harvest.

Overview of what will be covered in the article

The article will comprehensively cover the importance of growing onions at home, including choosing the right onion varieties based on climate and storage needs.

It will provide an overview of different onion types such as bulb onions and green onions, and discuss factors like soil preparation using organic fertilizers such as composted manure and blood meal.

Detailed guidance will be given on planting onion transplants and sets, optimizing soil structure with amendments like calcium nitrate and ammonium sulfate, and managing pests and diseases naturally. FAQs will address common issues such as yellowing leaves and enhancing bulb size through proper fertilization and watering techniques.

Choosing the Right Onion Varieties

Overview of different onion types (e.g., bulb onions, green onions)

When choosing the right onion varieties, it's crucial to consider different types such as bulb onions and green onions, each suited to specific culinary uses and growing conditions.

Bulb onions, which thrive in well-drained sandy soil amended with organic fertilizers like composted manure or blood meal, are ideal for harvesting in the fall after a full growing season.

Green onions, on the other hand, are typically harvested earlier and can be grown in containers or directly in the garden, benefiting from balanced fertilizers such as calcium nitrate or feather meal to promote steady leafy growth throughout the growing season.

Factors to consider when choosing varieties (climate, storage needs, etc.)

When selecting onion varieties, it's essential to consider factors such as climate suitability, storage needs, and the specific requirements of onion plants.

Varieties adapted to cooler climates may perform better in regions with shorter growing seasons, while those with longer storage capabilities are preferable for harvest and storage through the fall and winter months. Conducting soil testing helps determine nutrient deficiencies that can be corrected with amendments like well-rotted manure or balanced fertilizers such as chicken manure and blood meal, ensuring optimal soil structure and nutrient availability for planting onions.

Choosing varieties that match your soil type and amending with fresh manure or composted manure promotes healthy root development and robust growth, ultimately yielding quality bulbs at harvest time.

Soil Preparation and Organic Fertilizer

Onions prefer loose, well-drained soils that are high in fertility, slightly acidic (pH between 6.2-6.8), adequately irrigated, and in full sun. The looser the composition of your soil, the larger your onion bulbs will grow. Prepare your bed by turning under animal manure or compost. Make sure that it is fully broken down before planting. Compost composed of cedar or redwood is not an acceptable substitute for high quality compost.

Onions are heavy feeders, so make sure to provide plant food with plenty of nitrogen, phosphorus and ammonium sulfate. A good rule of thumb is to add one cup of equal parts blood meal and bone meal granule fertilizer every 10 feet of row. Be sure to use a quality organic fertilizer to improve soil ph for your onion crop.

Planting & Growing Onion Transplants

The potential for fungal diseases like downy mildew and pink root can be greatly reduced by avoiding beds where onions, garlic and other alliums have been grown within the last two years. This time period is a basic rule of thumb but, in general, "the longer the better."

As gophers are a major pest in onion beds, use gopher traps, wire barriers or wire baskets prior to planting.

Onion transplants can be grown in the fall or spring (planting time depends on your growing region). Onion transplants are often wilted when they arrive, but like other members of the hardy lily family, they will survive for about 2-3 weeks after being pulled from the soil. If you cannot plant them immediately upon receipt, either refrigerate them after soaking the roots in water, or mound soil around the roots and keep them moist until planted.

Before planting, trim the tops to approximately 3” and roots to ¼”. The roots will begin to grow rapidly once planted. Plant onion transplants 1-2” deep and 4-6” apart. Plant close as 3” apart if smaller onions are desired. Rows should be 18-24” apart or 12” apart if planting for commercial production.

If planted on raised beds which are approximately 20” wide, transplants should be planted in double-rows 2-4” from each edge. “Scatter planting” among vegetables in inter-planted gardens is sometimes utilized to ward off a variety of pests, but onions must not be forced to face heavy competition from surrounding neighbors.

Apply a layer of mulch such as straw, to help maintain moisture and protect the plants during the winter. Onions are hardy to 20°F, but in cold climate regions, protect your plants with a thicker layer of mulch (at least 2" deep).

Onion Sets

Onions are easy to grow from sets. Keep in mind though, onion sets perform the best in long day growing regions. Plant 1” deep and 1-3” apart. Harvest young plants for use as scallions, thinning to 3-4” spacing. Onions should be mulched and supplied with ample phosphorus while growing.

Mulch deeply (up to 8”) in cold winter areas but only lightly in milder climates. Mulching will suppress weeds, maintain soil moisture and protect bulbs from “heaving” (working their way out of the soil) during extreme temperature cycles.

Weed suppression is critical for onions; you can grow weeds or onions, but not both. Regular irrigation is necessary anytime rainfall is not sufficient to provide the 1” of water per week required to keep bulbs from splitting in hot dry soil or tasting bitter at harvest. Water up until the time you harvest!

Beds kept weed free and properly irrigated will require little additional care.

Harvesting & Storing

Onions are mature and ready to harvest when their tops have yellowed and begin to fall over. Finish bending the tops horizontal to the ground by hand or with a rake for those that have not completely fallen over. This bending will stop the sap from diverting energy into the leaves while the bulb matures.

Harvest bulbs after the tops have turned brown. Place the tops of one row over the bulbs of another to keep them from becoming sunburned. When the outer skins have dried (curing should be between 10-14 days), complete harvesting by clipping the roots, wiping off any remaining soil, and cutting the tops back to 1” above the bulb.

Onions keep best when kept separated; individual foil wrapped specimens can last up to a year under refrigeration. Pungent onion varieties, which have low water content, will keep longer than sweeter, moister types. Hanging an onion in a mesh bag, in a cool, dry, well-ventilated location and tied off to separate onions from each other, is the recommended method of preserving onion bulbs for maximum shelf life.

Plant an onion this fall or spring for enjoyment of a fresh, home-grown onion next summer!

Managing Onion Pests and Diseases

Common pests that affect onions (e.g., onion flies, thrips)

Managing onion pests and diseases involves proactive measures against common threats like onion flies and thrips. These pests can devastate onion plants during the growing season, affecting bulb development and causing leaves to turn yellow.

Utilizing natural and organic pest control methods, such as planting onions in well-drained soil and applying balanced fertilizers like chicken manure or blood meal, helps maintain plant health and resilience.

Recognizing early signs of infestation and promptly implementing measures such as mulching and proper watering practices can mitigate these risks and ensure a successful onion crop.

Natural and organic pest control methods

Natural and organic pest control methods for managing onion pests and diseases involve several effective strategies.

Planting onions in well-drained soil enriched with composted manure or organic fertilizers like blood meal and feather meal can enhance plant health and resilience against pests. Introducing beneficial cover crops or companion plants that deter pests, along with regular soil testing to maintain nutrient balance using amendments such as calcium nitrate or ammonium sulfate, helps prevent pest infestations.

Additionally, practicing crop rotation and removing weeds promptly can further reduce the risk of diseases and ensure a successful onion harvest.

Recognizing and preventing common onion diseases (e.g., onion rot, downy mildew)

Recognizing and preventing common onion diseases like onion rot and downy mildew is crucial for maintaining a healthy crop. These diseases often manifest as yellowing leaves or rotting bulbs, particularly in poorly drained or over-watered soils.

To prevent them, ensure proper soil structure and drainage through the use of well-rotted manure or composted manure, and avoid planting onions in areas prone to waterlogging.

Applying organic fertilizers such as chicken manure or blood meal can bolster onion plants' natural defenses, promoting good growth and reducing susceptibility to diseases during the growing season.

Conclusion

In conclusion, growing onions successfully involves selecting appropriate varieties based on climate and storage needs, enriching soil with organic fertilizers like composted manure and bone meal, and employing balanced fertilizers to support optimal growth. If you're looking to start your own crop, check out these Organic & Non-GMO Onion Seeds for sale to find the best varieties for your region.

Utilizing techniques such as slow-release and organic fertilizers, along with proper nutrient management including potassium, ensures robust plants and encourages bigger bulb development. Additionally, planting high-quality onion sets for sale can give you a head start on a successful harvest.

Managing pests and diseases through natural methods and maintaining soil health are essential practices for cultivating healthy onions, ultimately yielding flavorful and nutritious harvests.

FAQs About Organic Fertilizer for Onions & How to Grow Onions for Maximum Yield

• What is the best time to plant onions?

  • Plant onions in early spring as soon as the soil can be worked. In warmer climates, onions can also be planted in the fall.

• How should I fertilize onions?

  • Use a balanced fertilizer with a higher phosphorus and potassium content, or choose a slow-release organic fertilizer. Avoid excessive nitrogen, which can result in lush foliage but smaller bulbs.

• Are onions heavy feeders?

  • Yes, onions are heavy feeders, requiring adequate nutrients like phosphorus, potassium, and nitrogen throughout their growing season.

• Should I leave onions to dry before harvesting?

  • Yes, onions should be left in the ground until their tops have dried and fallen over. This allows them to mature fully and develop better storage qualities.

• Can I grow onions in containers?

  • Yes, onions can be grown in containers as long as the container is deep enough to accommodate their roots. Use a well-draining potting mix and fertilize regularly.

• How often should onions be watered?

  • Onions should be watered consistently to keep the soil moist but not waterlogged. Reduce watering as the bulbs mature to prevent rotting.

• Can onions be grown with other vegetables?

  • Yes, onions are compatible with many vegetables in the garden and can be interplanted to maximize space and deter pests.

• When should I stop watering onions?

  • Stop watering onions once their tops begin to fall over and yellow. This helps initiate the curing process before harvest.

• How do I store harvested onions?

  • After harvesting, cure onions by drying them in a well-ventilated area until the outer skins are dry and papery. Store them in a cool, dry place with good air circulation.

• Can I grow onions from seeds?

  • Yes, onions can be grown from seeds, sets (small bulbs), or transplants. Start seeds indoors in early spring and transplant them outdoors after the last frost date.