How To Plant Walla Walla Onions [ Full Guide ]

Walla Walla onions are a popular variety known for their sweet flavor and large size. They are ideal for planting in home gardens and are relatively easy to grow. When planting Walla Walla onions, it is essential to select the right location, prepare the soil properly, choose the right onion sets or seedlings, and employ recommended planting techniques to ensure a successful harvest. This guide will provide detailed instructions on how to plant Walla Walla onions effectively and yield a bountiful crop.

Quick Answer: How To Plant Walla Walla Onions

  1. Choose the right location for planting: Look for a sunny spot with well-drained soil.
  2. Prepare the soil for optimal growth: Ensure the soil is loose, fertile, and slightly acidic.
  3. Select and purchase onion sets or seedlings: Opt for high-quality Walla Walla onion sets or seedlings from reputable sources.
  4. Recommended planting techniques: Plant the onion sets at the right depth and spacing, and ensure adequate watering and care.

Now let’s delve into each step in detail.

Choosing The Right Location For Planting

Selecting the appropriate location for planting Walla Walla onions is crucial for their growth and development. These onions thrive in full sun and well-drained soil. When choosing a location, consider the following factors:

Sunlight: Walla Walla onions require a minimum of 6-8 hours of direct sunlight each day. Choose a spot in your garden that receives ample sunlight throughout the day.

Soil Drainage: Ensure the selected area has well-drained soil. Onions do not tolerate waterlogged conditions, as it can lead to rot and disease. If the soil tends to hold water, consider creating raised beds to improve drainage.

Soil pH: Walla Walla onions prefer slightly acidic soil with a pH between 6.0 and 6.8. Conduct a soil test to determine the pH of your soil. If the pH is too high, add elemental sulfur to lower it to the ideal range.

Preparing The Soil For Optimal Growth

Preparing the soil is essential for ensuring that Walla Walla onions have the right environment to grow and develop healthy bulbs. Here’s how to prepare the soil effectively:

Loosen the Soil: Begin by loosening the soil in the planting area to a depth of at least 6-8 inches. This will allow the onion roots to penetrate the soil easily and access essential nutrients and moisture.

Enrich the Soil: Incorporate well-rotted compost or aged manure into the soil to improve its fertility. This will provide the onions with the necessary nutrients for healthy growth.

Fertilization: Prior to planting, apply a balanced fertilizer with an N-P-K ratio of 10-10-10 according to the package instructions. This will provide an initial boost of nutrients to support early growth.

Weed Control: Remove any existing weeds from the planting area to prevent competition for nutrients and ensure the onions have ample space to grow unhindered.

Selecting And Purchasing Onion Sets Or Seedlings

Choosing high-quality onion sets or seedlings is vital for a successful Walla Walla onion crop. Whether you opt for onion sets, which are small bulbs, or seedlings, there are certain factors to consider when making your selection:

Quality: Select onion sets or seedlings from a reputable supplier or nursery to ensure good quality and disease-free plants.

Size: When choosing onion sets, look for bulbs that are firm, disease-free, and approximately the size of a marble. For seedlings, select healthy, green plants with no sign of wilting or disease.

Variety: Ensure that the sets or seedlings you purchase are specifically labeled as Walla Walla onions. This variety is known for its mild, sweet flavor and large size, making it a favorite among gardeners and cooks alike.

Quantity: Estimate the number of onions you wish to plant based on the available space in your garden. Purchase sufficient sets or seedlings to accommodate your planting area.

Timing: Purchase onion sets or seedlings at the appropriate time for planting in your region. Walla Walla onions are typically planted in early spring for a summer harvest.

Recommended Planting Techniques

Proper planting techniques are essential for the successful establishment of Walla Walla onions and the development of large, flavorful bulbs. Follow these recommended steps for planting:

Planting Depth: Set the onion sets or seedlings into the soil at a depth of approximately 1 inch. For sets, place them with the pointed side facing up. For seedlings, ensure that the root system is fully covered with soil, and the green top is exposed.

Spacing: Space the onion sets or seedlings approximately 4-6 inches apart in rows that are 12-18 inches apart. This spacing allows the plants to have enough room to grow and develop without crowding each other.

Watering: After planting, water the onions thoroughly to settle the soil and ensure good root-to-soil contact. Provide consistent moisture throughout the growing season, aiming for about 1 inch of water per week, either through rainfall or irrigation.

Mulching: Apply a layer of organic mulch, such as straw or shredded leaves, around the onions to conserve moisture, suppress weeds, and maintain a more consistent soil temperature.

Fertilization: As the onions grow, side-dress with a nitrogen-rich fertilizer when they are about 6 inches tall and again when they start to bulb. This will provide the additional nutrients needed for the development of large, healthy bulbs.

Weed Control: Regularly remove any weeds that emerge in the onion bed to prevent competition for nutrients and space. Be careful not to disturb the shallow roots of the onions while weeding.

Thinning: If the onions are planted too closely and begin to crowd each other as they grow, consider thinning them to the recommended spacing to ensure optimal bulb development.

Successfully planting Walla Walla onions involves careful consideration of the planting location, thorough soil preparation, selection of high-quality onion sets or seedlings, and adherence to recommended planting techniques. By following the steps outlined in this guide, you can create an ideal growing environment for Walla Walla onions and look forward to a rewarding harvest of sweet, flavorful bulbs. With the proper care and attention, your Walla Walla onion crop will thrive and provide a delicious addition to your culinary endeavors.

Proper Spacing And Depth For Optimal Growth

Walla Walla onions are a popular vegetable known for their mild and sweet flavor. These onions are prized by chefs and home gardeners alike for their exceptional taste and versatility in the kitchen.

Walla Walla onions are a long-day variety, which means they require a certain number of daylight hours to bulb properly. They thrive in cool, moist climates, making them particularly well-suited for the Pacific Northwest region of the United States. These onions can also be grown in other areas with similar climatic conditions.

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To give your Walla Walla onions enough space to grow and develop properly, it’s important to provide adequate spacing. Onions grown too close together may result in smaller bulbs or even no bulbs at all. Follow these guidelines to ensure optimal growth:

  1. Choose a sunny location: Walla Walla onions thrive in full sun and require at least 6-8 hours of direct sunlight each day. Select a spot in your garden that receives ample sunlight.

  2. Prepare the soil: Onions prefer well-drained soil with a pH level between 6.0 and 7.0. Enrich the soil with compost or well-rotted manure to improve its fertility and drainage. Avoid planting onions in an area that is prone to waterlogging, as excessive moisture can lead to rotting.

  3. Planting method: You can grow Walla Walla onions from seeds, sets (small bulbs), or transplants. Starting from transplants or sets is easier and more commonly recommended for home gardeners. Purchase high-quality, disease-free sets or transplants from your local nursery or reputable seed supplier.

  4. Spacing: The ideal spacing for Walla Walla onions is 4-6 inches apart in rows, with 12-18 inches between each row. This spacing allows enough room for the bulbs to develop without overcrowding.

  5. Planting depth: Onions should be planted with the tip of the bulb just barely showing above the soil surface. Dig a hole that is deep enough to accommodate the bulb and its roots, typically around 1 inch deep. Firmly press the soil around the bulb to ensure good contact and stability.

  6. Mulching: Once you have planted your onions, consider applying a layer of organic mulch around the plants. Mulch helps retain moisture in the soil, suppresses weed growth, and regulates soil temperature. Apply a thin layer of mulch, such as straw or dried grass clippings, to provide these beneficial effects.

Watering And Fertilizing Guidelines

Proper watering and regular fertilization are crucial to the success of your Walla Walla onion crop. Follow these guidelines to ensure your onions receive the right amount of water and nutrients:

  1. Watering: Onions require consistent moisture throughout the growing season, especially during bulb development. Aim to provide around 1 inch of water per week, either through rainfall or irrigation. Deep watering is preferred over frequent shallow watering, as it encourages the roots to grow deeper into the soil. Always water at the base of the plants and avoid wetting the foliage, as this can make the plants more susceptible to diseases.

  2. Mulching for moisture retention: Applying a layer of organic mulch around the onion plants will help retain moisture in the soil, reducing the frequency of watering. Mulch also prevents the growth of weeds that can compete with the onions for water and nutrients.

  3. Fertilizing: Onions are light to moderate feeders, meaning they require regular but not excessive fertilization. Before planting, incorporate a balanced, slow-release granular fertilizer into the soil according to the manufacturer’s instructions. This will provide a steady supply of nutrients throughout the season.

  4. Side dressing: As the onions grow, they can benefit from additional nitrogen fertilizer. Around four to six weeks after planting, when the plants have established their root systems, apply a nitrogen-rich fertilizer to boost growth. Follow the recommended application rate on the fertilizer packaging, as applying too much nitrogen can lead to excessive foliage growth at the expense of bulb formation.

  5. Compost tea foliar spray: While not necessary, some gardeners find that applying a compost tea foliar spray during the growing season can provide an extra nutritional boost for their onions. Homemade or store-bought compost tea can be sprayed on the foliage once a month. This method can help enhance plant health and increase disease resistance.

Managing Pests And Diseases In Onion Plants

Like other plants, Walla Walla onions can fall victim to various pests and diseases. However, with proper management and care, you can minimize the risk of damage and protect your crop. Here are some common pests and diseases that may affect onion plants and the recommended control methods:

  1. Onion thrips: These tiny, winged insects feed on the sap of onion plants, causing leaves to turn silvery and distorted. Regularly inspect your plants for thrip damage, particularly under the foliage. To control thrips, you can use insecticidal soaps or neem oil sprays. Apply according to the manufacturer’s instructions, ensuring thorough coverage of both sides of the leaves.

  2. Onion maggots: These pests are the larvae of small flies that lay their eggs near the base of onion plants. The larvae burrow into the onion bulb, causing rot and damage. To prevent onion maggots, use fine mesh netting or row covers to create a physical barrier around the plants. Begin covering the plants immediately after planting and keep them covered until harvest.

  3. Fungal diseases: Onion plants are susceptible to fungal diseases such as downy mildew and white rot. To minimize the risk of fungal infections, avoid overhead watering, as wet foliage creates an ideal environment for fungal growth. Practice crop rotation and avoid planting onions in the same location for consecutive years. If fungal diseases are a recurring problem, consider using fungicides labeled for use on onions. Always follow the instructions carefully when using any chemical treatments.

  4. Weeds: Weeds can compete with onions for nutrients, water, and space. Regularly remove weeds from the onion bed, especially during the early stages of growth when the plants are more vulnerable. Mulching can also help suppress weed growth.

Harvesting And Storing Walla Walla Onions

After months of care and patience, it’s finally time to harvest your Walla Walla onions. Here are some guidelines to help you determine when and how to harvest, as well as proper storage techniques:

  1. Harvesting time: Walla Walla onions are typically ready for harvest when the tops start to yellow and fall over. This usually occurs in late summer or early fall, around 100-120 days after planting. Gently push aside soil at the base of the bulb to check its size and maturity. When the bulbs have reached the desired size, it’s time to harvest.

  2. Lifting the bulbs: Carefully lift the onions out of the ground using a garden fork or shovel. Avoid pulling them up by their tops, as this can damage the bulbs and make them more prone to disease during storage.

  3. Curing: After harvesting, let the onions dry and cure for several weeks to improve their flavor and storage life. Lay the bulbs in a warm, dry, and well-ventilated area, such as a garage or covered porch. Spread them out in a single layer, allowing air to circulate around each bulb. Protect the onions from direct sunlight during this process.

  4. Trimming and cleaning: Once your onions have cured, remove any excess soil or dried foliage. Trim the roots to about half an inch in length, and trim the tops to about an inch above the bulb.

  5. Storage: Walla Walla onions have good storage potential when kept in optimal conditions. Store them in a cool, dry, and dark place with good ventilation, such as a basement or pantry. Avoid storing onions near potatoes or other fruits and vegetables that produce ethylene gas, as this can cause premature sprouting or spoilage. Check the onions regularly for any signs of rot or deterioration, and promptly remove any affected bulbs.

Planting Walla Walla onions can be a rewarding experience, resulting in a bountiful harvest of sweet and flavorful onions that can elevate your culinary creations. By following the proper spacing and depth guidelines, providing adequate water and fertilizer, managing pests and diseases, and harvesting and storing the onions correctly, you can ensure a successful crop year after year.

With a little time and effort, you'll soon be able to enjoy the fresh taste of Walla Walla onions in your favorite dishes, knowing that they were grown with care and expertise right in your own garden. Happy planting!

Tips For Growing Walla Walla Onions In Containers

Walla Walla onions are known for their sweet and mild flavor, making them a favorite among onion enthusiasts. Named after the region they were first grown in Walla Walla, Washington, these onions are a popular choice for home gardeners due to their versatility and delicious taste.

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While Walla Walla onions can be planted directly in the ground, they can also thrive in containers, making them suitable for gardeners with limited space. Here are some tips to help you grow Walla Walla onions successfully in containers:

1. Choose The Right Container

Select a container that is at least 12 inches deep to allow for proper root development. Make sure the container has drainage holes at the bottom to avoid waterlogging, which can lead to root rot. Plastic or ceramic containers work well for growing Walla Walla onions in containers.

2. Use Well-Draining Soil

Walla Walla onions prefer well-draining soil. Fill the container with a high-quality potting mix, amended with compost or well-rotted manure to provide the onions with the nutrients they need. Avoid using heavy soils or those that retain excess moisture.

3. Start With Onion Sets Or Transplants

Growing Walla Walla onions from seeds can be time-consuming, so it’s recommended to start with onion sets or transplants. Onion sets are small, partially grown bulbs, while transplants are young onion plants. Both options save you time and effort in the early stages of growth. Plant the sets or transplants in the container, leaving about 4-6 inches of space between each plant.

4. Provide Adequate Watering

Onions require consistent and even moisture throughout their growing season. Water the container when the top inch of soil feels dry to the touch. Be careful not to overwater, as onion bulbs can rot if they sit in waterlogged soil. Mulching the surface can help retain moisture and regulate soil temperature.

5. Feed The Onions Regularly

To promote healthy growth, feed your Walla Walla onions with a balanced fertilizer every four to six weeks. Look for fertilizers with an NPK ratio of 10-10-10 or similar. Follow the manufacturer’s instructions for application rates. Fertilizing will ensure your onions have sufficient nutrients for optimum growth.

6. Thin Out The Onions

Once the onions have started to grow, thin them out to allow for proper spacing. Depending on the size of your container, aim for about 4-6 inches of space between each onion. Thinning will prevent overcrowding, allowing individual onions to develop to their full size.

7. Monitor Pests And Diseases

Keep an eye out for common onion pests such as onion flies, thrips, or aphids. Inspect the leaves regularly and take appropriate measures if you notice any infestation. Additionally, pay attention to signs of diseases like onion rot or downy mildew. Prompt action can help prevent the spread of diseases and minimize damage.

8. Harvesting Walla Walla Onions

Walla Walla onions are usually ready for harvest when the foliage begins to turn yellow and flop over. Carefully lift the onions from the container, being mindful not to damage the bulbs. Allow them to cure in a warm, well-ventilated area for a couple of weeks to improve shelf life and flavor. Once fully cured, trim the tops and store the onions in a cool, dry place.

Companion Plants For Walla Walla Onions

Companion planting involves growing certain plants in close proximity to benefit each other in various ways. Here are some companion plants that can be beneficial when planting Walla Walla onions:

1. Carrots

Carrots and Walla Walla onions make great companions since they have different root depths. The onions repel the carrot fly, a common pest for carrots, while the aromatic presence of the carrots can help deter onion flies from the onions.

2. Beets

Beets and onions do well together as companion plants. The presence of beets can enhance the flavor of onions while reducing competition for nutrients. Beets also act as a natural weed suppressant and can help keep the soil evenly moist.

3. Lettuce

Lettuce can provide shade and help protect young Walla Walla onion plants from excessive heat and sunlight. The shallow rooting system of lettuce does not interfere with the growth of the onions. Additionally, the onions can act as an effective natural barrier against slugs and snails, which are notorious for damaging lettuce plants.

4. Chamomile

Chamomile is known for its ability to repel pests such as aphids and flies. Planting chamomile near Walla Walla onions can help protect them from these unwanted visitors. The flowers also attract beneficial insects like hoverflies and parasitic wasps, which help control pests in the garden.

5. Mint

Mint is a useful companion plant for Walla Walla onions, as it deters pests like ants and aphids. The strong scent of mint can mask the odor of the onions, making it more difficult for pests to locate them. However, be cautious with mint, as it can be invasive and take over the garden if not properly contained.

Common Mistakes To Avoid When Planting Walla Walla Onions

Although growing Walla Walla onions is relatively easy, there are some common mistakes that gardeners should avoid to ensure successful cultivation. Here are a few mistakes to watch out for:

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1. Planting Onions In Compacted Soil

Onions prefer loose and well-draining soil to thrive. Planting them in compacted soil can lead to poor root development and hinder their growth. Before planting, prepare the soil by loosening it with a garden fork or tiller. Incorporate organic matter like compost to improve the soil structure and drainage.

2. Overwatering Or Underwatering

Watering is one area where many gardeners make mistakes. Overwatering can cause root rot and lead to disease, while underwatering can result in stunted growth and small bulbs. It’s important to maintain consistent moisture levels, ensuring the soil is evenly moist but not waterlogged. Regularly check the soil moisture and adjust your watering schedule accordingly.

3. Ignoring Proper Spacing

Onions need adequate space to develop properly. Planting them too closely together can result in competition for nutrients, leading to smaller bulbs. Be mindful of the recommended spacing for Walla Walla onions and thin them out if necessary.

4. Not Providing Sufficient Sunlight

Onions require at least 6-8 hours of direct sunlight each day to grow and develop healthy bulbs. Planting them in a shady area can result in weak plants and smaller bulbs. Ensure that your container or garden bed receives adequate sunlight before planting Walla Walla onions.

5. Neglecting Weed Control

Weeds can compete with onions for nutrients, water, and space. It’s important to keep the area around the onions free from weeds to ensure their proper growth. Regularly pull out any weeds that appear and consider mulching the soil surface to suppress weed growth.

6. Skipping Fertilization

Onions are heavy feeders and need sufficient nutrients to grow into large, healthy bulbs. Skipping fertilization or using insufficient amounts can result in poor growth and smaller onions. Regularly fertilize your Walla Walla onions as recommended to support their nutritional needs.

7. Not Rotating Crops

Crop rotation is essential to prevent the build-up of pests and diseases in the soil. Planting Walla Walla onions in the same spot year after year can increase the risk of onion-related problems. Practice crop rotation by switching the location of your onions with other crops, preferably from different plant families, to maintain healthy soil conditions and reduce the likelihood of issues.

Culinary Tips And Recipe Ideas For Enjoying Walla Walla Onions

Walla Walla onions are a favorite among chefs and home cooks alike due to their mild, sweet flavor. Here are some culinary tips and recipe ideas to make the most of your Walla Walla onions:

1. Enjoy Them Raw

Walla Walla onions are perfect for consuming raw in salads or sandwiches. Their mild flavor adds a delightful sweetness and crunch to dishes. Slice them thinly and add them to your favorite summer salad or use them as a topping for burgers and sandwiches.

2. Caramelized Onions

Caramelizing Walla Walla onions brings out their natural sweetness and enhances their flavor. Slowly cook thinly sliced onions in butter or oil over low heat until they turn golden brown and develop a rich, sweet taste. Caramelized onions can be used as a topping for pizzas, incorporated into savory tarts, or added to pasta dishes.

3. Onion Rings

Who can resist a plate of crispy onion rings? Walla Walla onions make fantastic onion rings due to their sweet flavor and large size. Dip thick slices of onion in batter and fry until golden brown for a delicious appetizer or side dish.

4. French Onion Soup

Walla Walla onions are the perfect choice for making homemade French onion soup. Their sweetness pairs beautifully with the rich, savory broth. Slowly cook sliced onions until they caramelize, then add them to a flavorful beef or vegetable broth. Top it off with toasted bread and melted cheese for a comforting and satisfying meal.

5. Grilled Onions

Grilling Walla Walla onions brings out their natural sweetness and adds a smoky flavor. Slice onions into thick rounds, brush them with oil, and grill until tender and slightly charred. Grilled onions make a delicious side dish or can be used as a topping for grilled meats and burgers.


Growing Walla Walla onions can be a rewarding experience, as these flavorful vegetables can be enjoyed in a variety of culinary creations. Whether you choose to grow them in containers or in the ground, following the tips provided in this guide will help you achieve successful cultivation. By choosing the right companion plants, avoiding common mistakes, and trying out different recipes, you can make the most of these delicious and versatile onions. So go ahead and give Walla Walla onions a try in your garden and kitchen – you won’t be disappointed!


What Is The Best Time To Plant Walla Walla Onions?

Walla Walla onions are cool-season crops that thrive in cooler conditions, so it is best to plant them in early spring, just as the ground begins to warm up. Depending on your location, this could be anywhere from March to April.

How Deep Should You Plant Walla Walla Onion Bulbs?

Walla Walla onion bulbs should be planted with the top of the bulb sticking out of the soil, about 1 inch deep. Space the bulbs about 4 inches apart so they have room to grow.

What Type Of Soil Do Walla Walla Onions Prefer?

Walla Walla onions require well-drained soil that is rich in organic matter. They prefer slightly acidic soil with a pH between 6.0 and 6.8. If your soil is heavy, mix in some sand or compost to improve the drainage.

How Often Should Walla Walla Onions Be Watered?

Walla Walla onions need consistent moisture, so be sure to water them regularly throughout the growing season. The soil should stay evenly moist, but not saturated. If you are experiencing a dry spell, you may need to water them more frequently.

When Should Walla Walla Onions Be Harvested?

Walla Walla onions are typically ready for harvest in July or August, when the tops begin to dry out and fall over. Carefully lift the bulbs out of the soil and allow them to dry off in the sun for a few days. Once they are dry, you can store them in a cool, dry place for several months.