8 Reasons Your Spinach Plants Are Turning White or Yellow
Spinach leaves typically only turn white or yellow when there's a problem with your plant. There are actually several reasons this may happen, and many of these problems are treatable. In this article, gardening expert Madison Moulton examines why spinach leaves may turn white or yellow, and how to fix it.
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Spinach is the ideal vegetable for beginners and experienced gardeners alike. These leafy plants are easy to grow, packed with nutrients, and quick to harvest. Unfortunately, that doesn’t mean they are without problems. Yellowing leaves is a common issue in spinach plants, and many other popular plants, including pothos.
Just because you see these warning signs though, doesn’t mean it’s necessarily a major cause for alarm. Many of the causes have quick fixes and can be prevented by adjusting your care. Sometimes simply adjusting your watering schedule to allow for more or less water can do the trick.
Yellow leaves are also a natural sign of age. If you do not harvest the outer leaves of your spinach frequently, they will naturally turn yellow and fall off the plant. White leaves, on the other hand, are more troubling. This indicates a disease issue that usually cannot be rectified.Luckily, this and many of the causes of yellowing leaves are preventable. Let’s discuss how.
Spinach Leaves Turning Yellow
If your spinach leaves are turning yellow, there’s a few different causes for this. The good news is a yellowing plant usually means it’s something that can be remedied if you act quickly to preserve your plant. Let’s take a look at the most common reasons this happens to spinach plants.
Lack of Nutrients
The most common cause of yellowing leaves in spinach is a nutrient deficiency.
All plants need a range of nutrients to survive. These nutrients can be split into three categories:
- Macronutrients, needed in the largest amounts. These include the main nutrients you may have seen on fertilizers – NPK, or Nitrogen, Phosphorus and Potassium.
- Secondary nutrients, needed in fewer amounts but still vital to plant health. Some examples of secondary nutrients include calcium and magnesium.
- Micronutrients, needed in minimal amounts. Quantity varies by plant, with each requiring different amounts of things like iron or boron.
Deficiency in any of these nutrients can cause health problems for any plant, including spinach. If your spinach leaves are turning yellow, nitrogen is the most likely cause as it is the nutrient responsible for healthy leaf growth and chlorophyll development.
Boron deficiency is also known to cause yellowing. This can also be accompanied by stunted growth if the problem persists.
How To Fix It:
Start by conducting a soil test. This will help you identify which nutrient is causing the problem.
As nitrogen deficiency is most likely, you can fertilize with a high-nitrogen fertilizer straight away. But, if nitrogen isn’t causing the problem, this will only further the issue. It’s best to be safe and understand the cause completely through a soil test.
Once you have identified the problem, apply a fertilizer to target the deficiency according to package instructions.
Overfertilization
Fertilizer is an important part of vegetable gardening. However, while it may spur growth in the right amounts, it is possible to overdo it.
Rather than improving growth, overfertilizing will damage the roots and burn the leaves of your spinach. The build-up of excess nutrients, salts and chemicals in the soil has an adverse effect on health, placing the plant under severe stress.
When the plant is stressed, the leaves will begin to yellow and wilt. You may also notice brown spots or uneven discoloration across the leaves and stems.
How To Fix It:
No matter which type of fertilizer you choose, it’s vital to read the instructions thoroughly before applying.
Fertilizers come in different concentrations and have different application steps. Some should be diluted in water, while others are added straight to the soil. Some are slow-release, applied once every few months, while others need to be applied regularly to maintain nutrient levels.
If you do accidentally overdo it, you’ll need to flush the soil with water as best you can and hold off on fertilizing for several weeks.
Overfertilizing is quite difficult to fix, so prevention is always the best solution. Understand what type of fertilizer you’re dealing with before applying and only use as recommended.
Incorrect Soil pH
The correct soil is the starting point for a healthy plant. There are many properties that makeup soil health, from soil type to pH.
Soil pH is measured on a scale from 0 to 14. Acidic soils are those with a pH of below 7, alkaline soils with a pH above 7, and neutral soils are at exactly 7. Each plant has soil pH preferences, and some are fussier than others.
Spinach prefers slightly acidic soils with a pH of around 6.5. They can handle some variation, but nothing above the neutral zone. If your soil is too alkaline, it can cause your spinach leaves to turn yellow and remain discolored.
How To Fix It:
There are soil amendments available that will lower the pH. Acidic compounds like aluminum sulfate and sulfur are available at nurseries and are used commercially to rapidly lower pH levels. Over time, organic compounds like compost or peat moss can also lower the soil pH, but only marginally.
It’s best to make these amendments before planting to avoid disturbing the roots later on. Soil pH test kits are relatively inexpensive and will give you a more accurate picture of the levels. From there, you can determine how much product to add to resolve the issue.
Underwatering
Spinach is around 93% water. That means correct watering is a vital part of care (and taste). Too little or too much can have several negative consequences, including yellowing leaves.
Water carries nutrients around the plants, fills the cells to maintain structure, and is an important component in photosynthesis. When photosynthesis is limited, the plant cannot produce food and becomes stressed, causing the leaves to turn yellow.
In this case, the yellowing will occur after the leaves start to wilt. They will slowly change color to a light green and then yellow over time.
How To Fix It:
Luckily, the fix for this problem is easy. Simply water your plant and the leaves should return to normal. Heavily yellowed leaves are unlikely to change color, but slight discoloration can be rectified.
Modify your watering schedule to give the plants more water, especially in periods of high heat. They typically require watering every few days at the least but should be checked regularly to avoid underwatering. Alternatively, install irrigation around your plants on a timer to ensure they get the right amount of water.
Root Rot
Too much water can have the same impact as too little water. Overwatering can occur if the soil becomes waterlogged or if it doesn’t drain well enough, leaving the shallow root system sitting in moisture.
Excessively moist soil will stop oxygen from reaching the roots and cause a disease known as root rot. Root rot is caused by fungus and is difficult to get rid of once it sets in.
The roots become mushy, unable to take up water or nutrients. The leaves will start to wilt and turn yellow, as they do with underwatering.
How To Fix It:
Moderate cases of root rot can be solved by changing your watering routine. Leave the soil to dry out before the next watering and monitor the plant. If the problem is not resolved, you likely have a severe case of root rot and will need to pull the plants before the problem spreads.
Root rot is best avoided rather than dealt with when it hits. Ensure the soil is loose and well-draining before planting. Don’t let water pool around the roots and never water so much that the soil becomes waterlogged.
Blight
Spinach blight is one of the most common diseases afflicting these plants. It is also known as Cucumber Mosaic Virus, attacking cucumbers, peas, and other common garden vegetables.
Spinach blight is spread by destructive aphids in warm climates. It can also be transmitted by thrips, who reproduce and munch on the leaves in the process.
Plants with spinach blight will be easy to spot. The leaves will develop yellow discolored spots around the veins and can become deformed. Overall growth will be stunted. The disease can also spread to other susceptible plants in your vegetable garden if left untreated.
How To Fix It:
Unfortunately, spinach blight is difficult to get rid of once it takes hold. Removing the plants from your garden is safest to avoid spreading the problem.
While it is difficult to tackle, it’s not as difficult to prevent. Remove any debris around your plants and weed regularly to avoid attracting the pests that spread the disease. Row covers can also keep these pesky pests off not only your spinach but all the plants in your beds.
Keep your plants in good health by watering regularly and fertilizing often to allow their natural defenses to work to their full potential.
Downy Mildew
Downy Mildew, another common spinach disease, is caused by the parasite Peronospora farinose. It usually affects seedlings and young plants but can occur at any stage of growth.
Yellow spots start out small on the young growth and expand in a circular pattern. As they grow, they become tan in color and start to dry out. If you flip the leaves over, you may see purple fungus on the undersides.
Downy mildew is damaging and causes the leaves to become distorted and stunted. They may also curl inward if the infection is severe.
How To Fix It:
The best tool against downy mildew is prevention. Start by choosing a resistant variety, especially if the planting area is cool and moist where this fungus thrives.
Preventative fungicides can also stop downy mildew from taking hold, but will not resolve the problem once it has become established.
Spinach Leaves Turning White
If your leaves are turning white, there’s usually one primary cause with spinach, and that’s white rust. While there may be other less common reasons, this is the primary reason you’ll need to watch for in your garden. Let’s take a look.
White Rust
Albugo occidentalis, another fungus known to attack spinach plants, causes a devastating disease named white rust. Unfortunately, it is almost impossible to spot until the problem is too late.
Initial signs of infection are similar to downy mildew, with yellowing spots on the tops of the leaves that slowly grow. A look at the undersides will clarify which disease is the cause. While downy mildew produces a purple fungus underneath the leaves, white rust causes white blisters to appear.
As the problem spreads, entire leaves will start to turn white, indicating a severe white rust infection.
How To Fix It:
Once the leaves have turned white, there is no way to save the plant. You will need to pull them from the garden and destroy the plants to avoid spreading the fungus. Prevention is the only way to deal with white rust, by keeping the plants in good health and providing the right care.
Final Thoughts
If you notice the leaves of your spinach starting to turn yellow or white, there is no need to panic. Take a look at these signs and your care to identify which is most likely and apply these easy fixes. If none of those fixes work, then it may be time to remove the plant from your garden before disease spreads, and reevaluate your approach. Most likely it’s an easy fix, and you should have your plants back to good health in no time.
