Almost every gardener has to deal with the issue of their onion seedlings turning yellow at some point, as onions are a common vegetable crop. Before the yellowing affects the entire onion, it is usually safe to eat. The quality of the seedlings should preserve.

Onions are biennial bulbs in the same family as garlic, shallots, and chives. Blue-green, hollow, tubular leaves originate from a bulb in onions, essentially a modified leaf structure. The Bulb’s base sends out a radial network of roots, and the Bulb itself may even break the soil surface as the plant develops. Onions have a slow to moderate growth rate and are good to plant in the spring. It’s possible to grow their plants from seed, transplants, or sets.

Then, there’s the problem of yellowing onion seedlings, a common problem for gardeners. Many factors contribute to this phenomenon, but gardeners can safely attribute it to the Bulb’s feathers turning yellow and falling off as it matures. Onion sprouts that have turned yellow for other reasons are unsuitable and must address before harvest. By reading this guide, you will be able to know, Why Are the Tips of Onion Seedlings Turning Yellow.

Why Are the Tips of Onion Seedlings Turning Yellow | Guide

Let’s start,

Determine which of your seedling’s leaves have become yellow first. Cotyledons are the two initial leaves that sprout from a seedling after it has emerged from the earth. As it matures, the plant will produce leaves with distinctive shapes.

In the early stages of a plant’s development, the cotyledons serve an essential function. However, once the plant produces additional leaves, the cotyledons are no longer necessary and typically become yellow and fall off. All is well with your seedlings if these are the only leaves showing signs of yellowing.

You certainly have an issue if the larger, more mature leaves turn yellow, possibly due to some factors.

What are the reasons for onion seedlings turning yellow? 

Onion seedlings can become yellow for a variety of reasons. The most typical causes of onion seedlings turning yellow discuss below.

1. Lack of Light

Concern about lightning should rise when onion seedlings begin to turn yellow. Seedlings can impact by a lack of light, which causes them to turn yellow.

How do I treat it?

Seedlings require adequate lighting to thrive. You can use grow lights to cultivate them indoors. You can get by with a regular light bulb and a timer to keep it on for 12 hours a day for healthy seedlings rather than spending a ton of money on an expensive grow light.

2. Moisture Stress

Soil moisture stability is essential for the growth of onion plants. If the foliage turns yellow, it may indicate that onions are either getting too much or too little water.

You can put the finger into the soil to your second knuckle to determine if watering is the problem. Leaves becoming yellow could result from improper irrigation, especially if you find the ground either too wet or too dry.

How to solve it?

Apply a weekly dose of one inch of water to your scallion plants. If you need your onion seedlings to thrive, you must water them properly so that no one section becomes too soggy.

Mulch can also use to keep the soil moist and to distribute that moisture evenly. These three-in-one meter tests will help tell if you’re over- or under-watering your plants. They serve their purpose well and don’t break the bank.

3. Overcrowded Unwanted Plants

Unwanted plants are known as weeds. In other words, they are the tiny plants that sprout next to your larger ones.

When weeds surround scallions, their growth slows significantly. As a result of their weaker root systems, neighboring weeds pose a threat to these trees.

They might try to steal nutrients from your plants or, even worse, harm the roots and other sections of your plants. Weeds are not only unsightly, but they may also spread illness; therefore, it’s essential to eliminate them from your garden.

How do I treat it?

Select a weed-free garden bed as the starting point. If you can’t avoid it, get rid of the weeds before you plant the scallions.

Weeds are hardy plants that will return to their original location if you don’t get rid of the entire plant, including the roots. To that end, be sure to weed thoroughly.

Mulching your plants can also help keep unwanted weeds at bay. Cover your garden bed with grass clippings, pine straw, or small pieces of bark.

4. Overfeeding

Think about fertilizer. You may be over-fertilizing your seedlings if you do so frequently at this stage in their development. Fertilizer minerals can accumulate rapidly in small containers, suffocating young plants.

How do I treat it?

Do not apply any more fertilizer if you notice white deposits around the drainage holes after applying a lot of fertilizer. Instead, rinse the plant out gently with water.

If your onion seedlings have started to yellow and you haven’t used any, you can want to give them a single application to see if it recovers.

5. Diseases

Diseases caused by fungi, such as those listed below, are another possible cause of yellowing in green onions.

How does White Rot disease affect onion seedlings turning yellow? 

Infected plants are the source of this hazardous disease. Don’t plant seedlings that were grown in soil-based compost. Only use onion seed, onion sets, or onion bulbs purchased from licensed growers to ensure the highest quality. The symptoms of white rot include yellowing and wilting leaves and a white, fluffy fungal growth at the Bulb’s base that is only visible below ground.

How to solve it?

When onion rotting begins, there is no way to stop it. Take out the trash and discard the crop (do not compost). It’s not a good idea to plant onions again because the soil will contaminate for years.

How does Pink Root disease affect onion seedlings turning yellow? 

The fungal disease that spreads through the soil and hurts plant roots is also bad for garlic. The discoloration begins at the seeds and bulbs and might apply to the foliage. Weakened leaf tips and pink, crimson, or purple roots are possible symptoms. Over time, the disease will cause growth retardation and reduced crop output.

How to solve it?

Reduce the spread of the disease by rotating your crops. Furthermore, this will help stop the illness from spreading to other plants. Choose green onion cultivars known for their resistance to conditions for the healthiest onion produce possible. Fumigation can be an effective control method if you have a fungus epidemic in your garden.

How does Downy Mildew affect onion seedlings turning yellow? 

Initial symptoms of this fungus illness on plants are often innocuous yellow dots. But once the yellowing starts, it’s hard to stop the disease’s progression. Bulbs, stalks, and blooms may become waterlogged, and leaves may become limp and wilted.

How to solve it?

Don’t water your plants from above, and don’t use sprinklers. Ensure the soil drains well and the plant’s leaves and stems don’t become wet. To lessen the presence of fungi in the ground, follow the “three-year rotation rule.” Ensure the mother plant has no diseases before planting any seeds or bulbs.

How does Bulb Rot disease affect onion seedlings turning yellow? 

Yellowing and wilting of the leaves were early symptoms of this disease. The bulbs turn black and wet as well. It causes the bulbs to weaken and eventually rot.

It’s possible that some plants, and others, will develop abnormally slowly.

How to solve it?

Different approaches can take to eliminate this pest problem. Just ensure it’s not too late before the plant removes the ghost from bulb rot.

Delete the diseased soil and vegetation. The affected plants in your garden should be chopped down and removed to prevent the spread of the disease. Onions, as you may be aware, are not cooperative when faced with rivals. Additionally, weeds may spread illnesses that have the potential to ruin your crop. 

6. Pests Attack

The onion nematodes, onion thrips, and the leek moth are all responsible for the yellowing of onion seedlings.

How do Onion Thrips affect onion seedlings turning yellow?

The yellowing of onion leaves is another symptom of onion thrips infestations. Onion thrips are smaller than aphids but feed on the same cell sap. They cause the leaves of onion plants to wilt and turn yellow.

Even if you plant your seedlings in the best spot and implement all agricultural procedures, onions can still suffer from this pest because onion thrips overwinter in the soil and the bulbs for the following year’s planting.

How to get rid of onion thrips?

Drop the seeds into the water at 110-120°F a quarter of an hour before planting. Then you should soak them with cold water for 10 minutes to kill any lingering Onion thrips.

If pests are already present, it is unlikely that a home remedy would work, and a pesticide will be required. Onion thrips can prevent by using a pesticide as directed.

How do Nematodes affect onion seedlings turning yellow?

Onions are susceptible to damage from these nematodes, which manifests as leaf yellowing and withering. They are found in the ground and might cause growth problems.

How to get rid of nematodes?

Look back at previous harvests. You may have accidentally planted leeks, chives, or lettuce, which all harbor potentially harmful nematodes.

Do not plant these crops again for at least three years after an infestation. It is essential to sterilize gardening tools and clean anything that will touch the soil.

How does Ceutorhynchus Suturalis affect onion seedlings turning yellow?

Ceutorhynchus suturalis larvae consume onion seedlings, causing them to fade to a pale green before turning yellow, wilting, and eventually dying. Most onion crops will be lost if this pest is allowed to go unchecked.

The most annoying thing about this pest is that it can spread from one plot to another, even though you rotate crops, fertilize, irrigate, and otherwise take good care of the land.

How to get rid of Ceutorhynchus Suturalis?

Digging up the soil, removing and burning plant residues, and practicing crop rotations reduce beetle populations on your plots. Wood ash, mustard, or pepper placed on the beds’ soil will deter the beetles.

Without a significant population boom, these beetles will likely have to be collected by hand. However, the insecticide must apply well as directed if there are several bugs.

How do Onion Maggots affect onion seedlings turning yellow? 

These are frequent pests of onions and could do significant damage if not managed. The larvae will eat the plant’s roots and bulbs, and they may also tunnel through the stems and leaves.

How to get rid of onion maggots?

Instead of using harmful chemicals, natural biological predators can rid your plants of these pests.

Onion maggots are a nuisance that can reduce with the help of predatory ground beetles and the parasitic worm Steinernema feltiae. After picking the green onions, rotate the vegetables in your garden bed and wait until the soil temperature reaches 95 ⁰F before planting anything.

How does Leek Moth affect onion seedlings turning yellow?

The Leek moth is most active in warm, dry conditions with little precipitation. The Leek moth butterfly emerges at this time of year, looking somewhat dissimilar to common house moths. The larvae that develop from the moths’ eggs are harmful.

The presence of the larvae causes the onion leaves to be dry and yellow at the tips, and eventually the entire feathers.

How to get rid of leek moth?

To successfully manage the Leek moth, one must have a firm grasp on the insect’s biology. For instance, the Leek moth’s egg-laying device inserts the segment closest to the Bulb into the ground. When they emerge from their eggs, the tiny, yellow caterpillars will measure around 0.4 inches in length.

Feathers turn yellow and wilt when the hatchings travel to the feathers, enter them, and start nibbling on the tissue from the inside.

Traditional pest management techniques for the Leek moth include treating the feathers and surrounding soil with well-dispersed cooking ash and tobacco. You can also spray the soil and plants with a garlic infusion (a few cloves per 0.26 Gal of water) for leek moths.

How does Ditylenchus Dipsaci affect onion seedlings turning yellow?

The stem nematode is another culprit in the unusual coloring of onion leaves. The rot spreads, the leaves turn plate-shaped and yellow, and eventually die.

Nematodes rarely exceed 1.5 mm in length, yet their destructive potential is vast. Nematodes can survive in the soil for at least ten years and often much longer after introducing.

How to get rid of Ditylenchus dipsaci?

Before planting, onion seedlings should soak for 30 minutes in water heated to 113 degrees Fahrenheit (45 degrees Celsius) above zero and then for another 30 minutes in salt water.

The standard amount of nutrients for infusing 20-30 square feet of soil with marigolds is 4-6 lb per pail of water.

How to care for onion seedlings? 

Why Are the Tips of Onion Seedlings Turning Yellow | Guide

The success or failure of onion seedlings depends on how well you care for them. To foster deep, healthy roots, provide ample moisture, sunlight, and occasional mild pinching.

1. Air Circulation 

As soon as the sprouts appear, take the plastic off to give the plants a breath of fresh air. Indoor seedlings can benefit from having an oscillating fan running on low in the vicinity, as this will create the illusion of breeze and encourage healthy growth.

2. Water

They require consistently damp conditions but not standing water. A moisture meter will help you get the ideal consistency.

3. Light

Once onion seeds germinate, they need to expose to light for 12 hours per day. Even if you have a sunny window, doing this inside is challenging. A practical method for preventing legginess is to position a grow lamp such that it is just an inch or so above the plant’s canopy.

4. Fertilizer

After three weeks, a once-weekly application of a dilute organic fertilizer is appropriate. Fish emulsion and compost tea are other excellent choices.

5. Thinning 

 Recommend to thin them so that there is only one plant every 4-6 inches in the garden or one per cell or pellet indoors.

When do I transplant onion seedlings into the garden? 

Early in the spring, when your soil is workable and the temperatures at night remain above freezing, is the time to plant onion seedlings in the garden.

Even though they can tolerate the cold, they must harden off before being released into the wild. While they may survive minor frost, it’s preferable to protect them from a late freeze by covering them.

How do I keep the onion leaves from turning yellow after transplanting the seedlings?

Therefore, proper treatment of the plots, timely watering, modern techniques to control pests and diseases, and adherence to other cultural laws are required to preserve Onion leaves in a healthy color before harvest.

1. Water plants properly. 

Consistent watering requires to maintain the onion bulb’s swelling. A weekly soaking of 1 inch should suffice. Overwatering or leaving the bulbs in damp soil will cause them to decay. Mulch, even if it’s just a thin covering, can keep the soil moist for longer.

2. Keep an eye on temperature and humidity. 

When planting onion seeds, ensure the soil is at least 40⁰F. Onions thrive in temperatures ranging from around 64 to about 75⁰F. As long as the soil’s moisture requirements meet, humidity is usually not a problem.

3. Provide proper lighting

Onions require a minimum of six hours of daily sunshine from full sun to mature well. When it comes to onions, more sunlight is always better.

4. Make sure to use the crop rotation method.

Remember that planting onions in the same spot more than once every four years is not a good idea since it encourages the buildup of pests and illnesses and depletes the soil of nutrients.

5. Implement proper fertilization.

Both too little and too much fertilizer are ineffective, so it’s vital to get the balance right. Onions require a lot of food. You may encourage giant bulbs by fertilizing them every few weeks with a high-nitrogen fertilizer to promote leaf growth.

Amounts should use as directed on the packaging. When the earth cracks around the area where the Bulb is developing, the foliage growth cycle is complete, and no additional fertilizer should apply.

6. Use fertile soil. 

To grow onions successfully, you need to start with good soil. Soil with the best levels of organic matter and excellent drainage is essential. A sandy loam would be ideal. Also, an acidic to neutral pH range is perfect for soil.

7. Pay attention to pests and insect attacks. 

When the leaves of an onion begin to turn yellow, they should be removed and burned. Thus, diseases or pests prevent from spreading.

8. Consider the pollination

In most gardens, onions are treated as annuals and harvested before they set to blossom. Onion blooms pollinate by wind and many insects, including bees.

6 Best Onion varieties to grow

The best onion varieties for your garden are listed below and include lengthy day varieties, short day varieties, and day-neutral varieties.

1. Ailsa Craig 

These massive heirlooms have golden skin and a mellow, sweet flavor. Shorter stalks ensure that these varieties, which are also called “Kelsae Sweet Giant,” can be preserved for a more extended period than fresh varieties.

The vast, white bulbs of the long-day cultivar ‘Ailsa Craig’ can be harvested after about 100 days.

2. Crystal White Wax 

These small, circular bulbs mature in around 95 days and are excellent for pickling.

Mild and sweet, these bulbs grow big in the South yet small as pearls up north. Do you wish to benefit from the warmer climate’s smaller, pearl-sized selection? Pick them earlier!

3. Red Burgundy

This short-day globe variety has giant bulbs measuring 3 to 4 inches in diameter with red rings and dark red skins, and they are at their peak flavor when eaten right away.

The ‘Red Burgundy’ ancestral variety has a moderately sweet flavor and is resistant to pink root disease.

4. Utah yellow sweet Spanish

Like the previous one, this long-day cultivar is very delicious and yields enormous bulbs in about 115 days. They’re mild and sugary, perfect for midday snacking.

This heirloom cultivar is ideal if you live in the West of the United States because it does well in our climate. The ability to store things is another strength.

5. White Sweet Spanish 

These are a little white variety that is great for adding a sweet and mild flavor to fresh summer salads. You can count on them to yield three-inch-diameter bulbs that are white and compact. This variety matures in about 110 days and shouldn’t be stored.

This type, which thrives in the long summer days of the North, is ideal for those regions’ gardens. However, a new green variety can be cultivated and harvested in the South in the fall.

6. Candy

This gorgeous and consistent performer is an intermediate or day-neutral type with a pale yellow flesh and papery skin. The long, thin stalk of the ‘Candy’ species doesn’t retain much moisture. Therefore, it’s known to keep well in storage provided it’s well cured.

These are crisp and tart with just a hint of heat. After 200 days, they’ll be ready to harvest and eat, and they’re tasty at any stage.

Watch What happens if onion seedlings don’t receive enough light | Video

Top 5 FAQs & answers related to Why are the tips of onion seedlings turning yellow

How often should you water onions?

The output of your onions depends on giving your onion plants just the right amount of water, yet too much water will cause your onions to rot in the ground and spread disease.
A standard 12-week growth season requires an inch of water per week from irrigation, more or less depending on the amount of natural precipitation.

Why are the tips of my onion plants turning brown? 

Onions suffer from a fungus that causes the leaves to die back at the tips. Alternaria, a type of fungus, is thought to be the root cause. It usually occurs in poorly developing plants.

Why are onion tops turning yellow? 

The soil around green onion plants must be consistently moist to grow well. If the foliage begins to turn yellow, it may signify that plants are getting too much or too little water.

Can I grow onions from onion tops? 

Many people recycle onion scraps by starting new green shoots at the onion’s base. However, by employing the above procedure, one can regenerate a piece into a full-sized onion indoors on a windowsill or outside in an onion patch. Because the cycle might last anywhere from 90 to 120 days, all that is required is patience.

How many onion seeds do you plant per hole? 

For optimal growth, sow 4-8 onion seeds per hole. The germination rates of modern sources are higher, so you can use fewer of them.


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