How to Grow Yellow, Red, Purple, and Pearl Onions: Complete Guide

Growing onions at home gives you fresh flavor and control over what ends up in your kitchen. You can grow yellow, red, purple, and pearl onions in garden beds, containers, or even from scraps. You can plant yellow onion bulbs, sprouted onions, or even onion bottoms from your kitchen to grow a healthy new crop.

Yellow onions are popular for their storage life and mild flavor, while red and purple onions add color and sharpness to meals. If you want smaller options, pearl onions can be planted close together to form compact bulbs. Each type has simple steps for planting and care, and most require only well-drained soil, sunlight, and steady watering.

Whether you start from bulbs, seeds, or scraps, onions are flexible and rewarding. With the right method, you can grow them in raised beds, pots, or bags, and enjoy a steady supply for cooking or storing through the season.

Key Takeaways

• Learn the best ways to grow different types of onions
• Discover simple methods to plant from bulbs, scraps, or containers
• Get tips for care, harvesting, and storing onions

Understanding Onion Types and Varieties

Onions (Allium cepa) come in many forms, and each type has unique characteristics that affect how you grow, harvest, and use them. Differences in color, size, flavor, and growing requirements determine which onion works best in your garden and kitchen.

Yellow, Red, Purple, and Pearl Onion Characteristics

Yellow onions are the most common type and include popular varieties like Yellow Granex. They have a balance of sweetness and sharpness, making them versatile for cooking. They also store well, which is why they are often called storage onions.

Red onions have a mild, sometimes slightly sweet flavor. Varieties like Red Creole are often eaten raw in salads, sandwiches, or salsas. Their purple-red skin and crisp texture make them a good choice when you want color and crunch.

Purple onions, often grouped with reds, tend to be slightly spicier. They are less common in storage but work well for fresh use.

Pearl onions are small, round, and mild. They are sometimes called mini onions and are often used in pickling, stews, or roasted whole. Varieties like White Bermuda or cipollini onions fall into this category.

Short-Day, Long-Day, and Day-Neutral Onions

Onion growth depends on daylight length. Short-day onions form bulbs when days reach 10–12 hours of sunlight. They grow best in southern regions with mild winters. Varieties include Yellow Granex and Red Creole.

Long-day onions need 14–16 hours of daylight to form bulbs. They thrive in northern climates with long summer days. Classic storage onions, such as yellow and white types, fall into this category.

Day-neutral onions (also called intermediate-day onions) bulb with 12–14 hours of daylight. They adapt to a wide range of climates, making them a good choice if you live in a region with unpredictable seasons.

Understanding these categories helps you avoid planting onions that never bulb properly in your region.

Choosing the Right Onion for Your Region

Your location is the most important factor when deciding which onion varieties to plant. If you live in the South, short-day onions like Yellow Granex or White Bermuda will develop bulbs successfully. In the North, long-day onions such as Walla Walla or classic yellow storage onions are better suited.

If you are in a middle latitude, day-neutral onions give you flexibility. Varieties like Candy can adapt to both northern and southern conditions.

You should also consider how you plan to use your onions. For long-term storage, choose firm yellow or white onions. For fresh eating, red onions, scallions, or bunching onions are better. If you want specialty uses, try pearl onions for pickling or shallots and leeks for more delicate flavors.

By matching onion type to your climate and culinary needs, you increase your chances of a successful harvest. For a detailed overview of onion varieties and their uses, you can explore how different types fit into cooking and storage.

How to Grow Yellow Onions

Yellow onions grow well in many climates, but success depends on choosing the right type, preparing the soil, and giving them proper care. You can start with bulbs, seeds, or sets, and the time to harvest depends on the variety and your region.

Planting Yellow Onion Bulbs

Bulbs, also called onion sets, are the easiest way to start growing yellow onions. Choose firm, small sets about the size of a marble. Avoid soft or sprouted ones.

Plant them in well-drained soil with a pH between 6.0 and 7.0. Space bulbs 4–6 inches apart in rows 12–18 inches apart. Place each bulb with the pointed end facing up and cover it with 1 inch of soil.

Yellow onions need full sun, at least 6–8 hours daily. Water 1 inch per week, keeping the soil moist but not soggy. Fertilize with a balanced mix that supports root and bulb growth. You can learn more about soil and spacing needs from this yellow onion growing guide.

Growing Yellow Onions from Seeds

Starting from onion seeds takes longer but gives you access to more varieties, including long-day and short-day onions. Long-day onions grow best in northern regions, while short-day onions perform well in southern areas with mild winters.

Sow seeds indoors 8–10 weeks before your last frost date. Plant them ¼ inch deep in seed trays filled with rich potting mix. Keep the soil evenly moist and maintain temperatures around 65–70°F for good germination.

Once seedlings are 4–5 inches tall, trim tops to about 3 inches to encourage stronger roots. Transplant them outdoors once the soil is workable and temperatures stay above freezing. For more details on choosing the right variety, check this guide on growing onions.

How Long to Grow Yellow Onions

The time it takes to grow yellow onions depends on whether you start from bulbs, sets, or seeds. Bulbs and sets mature faster, usually in 90–120 days. Seeds take longer, often 110–160 days, depending on the variety.

Onions are ready to harvest when the tops fall over and begin to dry out. Stop watering at this stage to allow bulbs to cure in the soil for a few days. After pulling them, let them dry in a shaded, well-ventilated area before storage.

Short-day onions tend to mature earlier, while long-day onions need longer daylight hours and take more time. For a full breakdown of planting and harvest timing, see this onion planting guide.

Alternative Methods for Growing Yellow Onions

You can grow yellow onions in several ways beyond starting from seed. Each method has its own steps, timing, and care requirements, but all can give you a steady supply of fresh onions for your kitchen.

How to Grow Yellow Onions from Bulbs

Growing from bulbs, also called sets, is one of the most reliable methods. Choose firm, disease-free bulbs labeled as yellow onion or storage onion varieties. Popular types include Yellow Granex and Texas Grano.

Prepare well-draining soil by loosening it about 12 inches deep and mixing in compost. Onions prefer a pH between 6.0 and 7.0. Plant bulbs 1–2 inches deep with the pointed end up, spacing them 4–6 inches apart in rows about 12 inches wide.

Water the soil right after planting and keep it evenly moist, about 1 inch of water per week. Mulching helps control weeds and retain moisture. Yellow onions are ready to harvest once the tops yellow and fall over, usually in 3–4 months. Learn more about planting yellow onion bulbs.

How to Grow Yellow Onions from Scraps

You can regrow yellow onions from kitchen scraps by using the root end. Cut the onion so the bottom with the roots remains intact, leaving about 1 inch of flesh above the roots.

Place the root end in a shallow dish with water, ensuring only the base touches the water. Change the water every couple of days to prevent rot. Within a week, new green shoots and roots should appear.

Once roots are established, move the scrap to soil in a pot or garden bed. Plant it root-side down and cover lightly with soil. Keep the soil moist and provide full sun. While this method may not produce large bulbs, you can harvest green onion tops for cooking.

How to Plant Yellow Onions That Have Sprouted

Sprouted onions can still be planted and grown. Separate the onion into individual sprouts, as each can produce its own bulb. Peel away the outer layers carefully so the sprouts remain intact.

Plant each sprout in soil about 1–2 inches deep and 4–6 inches apart. Position them with the green shoot facing up. Use fertile, well-draining soil and water them consistently.

Sprouted onions often grow faster because the plant has already begun developing. You can expect smaller bulbs compared to starting with fresh seedlings or bulbs, but they are still usable. This method helps reduce food waste while giving you a modest harvest of yellow onions.

Cultivating Red and Purple Onions

Red and purple onions both grow well in home gardens when you match the right variety to your climate and soil. You can start them from scraps, plant them in containers, or raise them from sets or seedlings in garden beds.

Growing Red Onions from Scraps

You can regrow red onions from kitchen scraps if you have a bulb with roots still attached. Cut the onion so that the root end remains intact with about half an inch of flesh. Place this piece in moist soil with the roots facing down.

Keep the soil damp but not waterlogged. Within a week or two, you should see green shoots appear. These shoots will continue to grow into new onion plants.

Once the seedlings are a few inches tall, thin them out so each plant has space to form a bulb. Leave about 4–6 inches between each one. This spacing ensures the onions develop properly without competing for nutrients.

While growing from scraps is slower than using onion sets, it reduces waste and gives you a steady supply of fresh onions.

How to Grow Red Onions in Containers

Red onions adapt well to containers if you use a pot that is at least 10–12 inches deep. Make sure the container has drainage holes to prevent root rot. Use a loose, well-draining potting mix rather than heavy garden soil.

Plant onion sets or seedlings about 4 inches apart in rows. Cover them with 1 inch of soil, leaving the tips slightly visible. Water regularly so the soil stays evenly moist.

Containers dry out faster than garden beds, so check moisture more often, especially in warm weather. Fertilize every few weeks with a nitrogen-rich fertilizer to support leafy growth before bulbs form.

If you live in a cooler climate, place the container in full sun for at least 6 hours per day. In warmer regions, some afternoon shade can prevent stress on the plants.

How to Grow Purple Onions

Purple onions need plenty of sunlight and loose, fertile soil. They respond best when planted as onion sets or seedlings rather than seeds, since this shortens the time to harvest.

Space the sets 4–6 inches apart in rows 12 inches wide. Plant them shallow, with only about an inch of soil covering the top. Planting too deep can slow bulb growth.

Purple onions usually take 90–120 days to mature, depending on the variety. Keep the soil evenly moist and add a light mulch to hold in water and reduce weeds.

Harvest when the tops begin to yellow and fall over. Gently pull the bulbs, then cure them in a dry, shaded area with good airflow for several weeks before storing.

For more detailed steps on timing and soil preparation, you can review guidance on how to grow purple onions.

Planting and Growing Pearl Onions

Pearl onions stay small because of planting methods, spacing, and harvest timing. They grow best in full sun, loose soil, and with close spacing that limits bulb size.

How to Plant Pearl Onions

You can start pearl onions from seeds, sets, or transplants. Seeds should be sown about ¼ inch deep, while sets and transplants go 1 to 1½ inches deep. Keep rows or containers in full sun with well-drained soil.

Spacing affects size. If you want true mini onions, place bulbs or seedlings ½ to 2 inches apart. Closer spacing produces smaller bulbs, while wider spacing allows them to grow larger.

For timing, plant in early spring about a month before the last frost or in fall, 4–6 weeks before the first frost. Pearl onions usually mature in 60–90 days depending on variety and daylight.

Short-day varieties like Crystal White Wax and Red Creole perform well in southern regions, while Pompeii and Purplette are good for cooler climates. You can find more details on growing pearl onions including variety options.

How to Grow Pearl Onions

Once planted, keep the soil evenly moist but not waterlogged. A layer of mulch helps retain moisture and suppress weeds. Fertilize lightly with a balanced fertilizer to encourage steady growth without forcing the bulbs too large.

Watch for weeds, since onions have shallow roots. Hand-pull weeds instead of hoeing to avoid damaging the bulbs.

Pearl onions are ready to harvest when the tops begin to yellow and fall over. Gently dig them up, cure them in a ventilated space for a week, and store them in a cool, dry place. Because of their size, they usually keep for about a month, though you can pickle or freeze them for longer storage.

For more step-by-step guidance, see this pearl onion growing guide.

Care, Harvest, and Storage Tips

Onions need steady care during the growing season, careful timing at harvest, and proper curing for long storage. Paying attention to water, soil nutrition, pests, and drying methods helps you enjoy firm, flavorful homegrown onions for months.

Watering and Fertilization

Onions grow shallow roots, so they need consistent moisture. Water about 1 inch per week, either from rainfall or irrigation. Avoid overwatering, since soggy soil can cause rot. Mulching with straw or grass clippings helps keep the soil moist and reduces temperature swings.

Fertilize onions every few weeks with a balanced fertilizer. A mix higher in nitrogen early in the season encourages strong leaf growth, which directly supports bulb development. Later in the season, switch to a fertilizer with less nitrogen to allow bulbs to mature.

You can side-dress with compost or a slow-release fertilizer halfway through the season. Keep fertilizer a few inches away from the bulbs to avoid burning the roots. Healthy growth at this stage sets the foundation for larger, better-quality storage onions.

Weed and Pest Management

Weeds compete with onions for nutrients and water. Since onions have shallow roots, hand-pulling or using a hoe carefully around the plants is the safest method. A light mulch layer also helps suppress weeds.

Pests such as onion maggots can cause serious damage. These small larvae feed on the roots and bulbs, leading to stunted growth or rotting. To reduce risk, rotate crops each year and avoid planting onions in the same spot where other alliums grew recently.

Covering young plants with row covers can prevent adult flies from laying eggs. If you notice soft, damaged bulbs, remove them quickly to stop the spread. Keeping the garden clean and free of plant debris also lowers pest problems.

Harvesting and Storing Onions

Onions are ready to harvest when the tops fall over and begin to dry. Stop watering at this stage to allow bulbs to firm up. Gently pull the onions and lay them out in a single layer to dry in a warm, shaded, well-ventilated area.

Curing usually takes 2–3 weeks. The outer skins should become papery, and the necks should feel dry. Trim the tops to about 1 inch and clip the roots once curing is complete.

Store onions in mesh bags, crates, or baskets where air can circulate. Keep them in a cool, dry place between 32–50°F. Properly cured onions can last several months, and some varieties can store up to a year if handled carefully, as explained in this guide on harvesting and curing onions.

Frequently Asked Questions

You can grow onions in several ways, including from bulbs, scraps, or sets. Each method has its own timeline and care needs, and the steps vary depending on whether you are planting yellow, red, purple, or pearl onions.

How to grow yellow onions from scraps?

Place the root end of a used yellow onion in a shallow dish with water, making sure the roots are facing down. Keep the dish in a sunny spot and change the water every few days. Once green shoots appear and roots grow stronger, transfer the scrap into soil for continued growth.

What is the best way to plant sprouted yellow onions?

Separate the sprouts if multiple bulbs have formed. Plant each sprout in well-draining soil with the green shoot above the surface and the bulb covered. Space them about 4–6 inches apart to give the bulbs room to develop.

How long does it take for yellow onions to grow from bulbs?

Yellow onions usually take about 3–5 months to mature after planting bulbs. The exact time depends on the variety and growing conditions. Bulbs are ready when the tops turn yellow and fall over.

Can you grow red onions from scraps, and if so, how?

Yes, you can grow red onions from scraps in the same way as yellow onions. Place the root base in water until shoots and roots form. Then move the scrap to soil, keeping it in full sun while watering consistently.

What are the steps to grow purple onions?

Choose a sunny location with loose, well-draining soil. Plant sets or bulbs about 1 inch deep and 4–6 inches apart. Water regularly, keep weeds down with mulch, and harvest when the tops fall over and dry out.

What is the correct method for planting pearl onions?

Plant pearl onion sets or bulbs closely together, about 1–2 inches apart, since they stay small. Place them 1 inch deep in fertile, well-draining soil. Keep the soil moist but not waterlogged until harvest time, which usually comes within 60–90 days.