Why Is My Parsley Turning Yellow? 7 Causes and What to Do

I love growing parsley in my garden, and I’ve usually found that it’s a pretty low-maintenance crop- most herbs are, and that’s one thing I like about them! But there are a couple of times every year that I walk out to the garden and think “hmmm, why is my parsley turning yellow?”

The most common reasons for parsley turning yellow are:

• Overwatering
• Under-watering
• Nutrient deficiencies
• Not enough sunlight
• Normal aging
• Root constriction
• Pests

I’ve run up against most of these issues at one time or another. In this post, I’ll talk about each problem in detail and give you tips for addressing it. Fortunately, I’ve found that yellowing leaves on parsley are typically not a big deal as long as you identify the problem quickly and take care of it.

So let’s get started and get your parsley back on track!

Why is My Parsley Turning Yellow: 7 Reasons

The condition of plants losing their normal green color and turning yellow is called chlorosis, and it can happen for several reasons. So identifying the true problem is key to tackling it quickly and correctly.

If you don’t have time to read the details, here’s a quick breakdown of the key points:

Here are the reasons for parsley turning yellow and how to tackle them:

1. Overwatering

Plants primarily meet their need for moisture by absorbing water through their roots, so keeping the soil sufficiently moist is essential for your parsley plant to thrive.

But soil that’s too wet can harm your parsley in two ways:

• Plants also absorb oxygen from the soil through their root system, known as root respiration. If the soil’s air pockets are filled with water, oxygen absorption can’t happen.
• Overly wet soil can cause root rot, which is bacteria and fungi that eat away the fine root tips where water and nutrient absorption happen.

In both cases, the roots can’t do their job of supporting the plant. In its weakened state, the plant cuts off energy to some of its leaves, causing them to turn yellow and die.

To find out if your parsley is overwatered, feel the soil and think about your watering habits. Daily watering is usually too much, so if you’ve been giving water that frequently and the soil feels wet to the touch, your plant is probably overwatered.

How to Fix Overwatering Problems

Stop all watering immediately and allow the soil to dry out. In the early stages of overwatering, this should be enough to help your plant bounce back.

Parsley is a pretty tough plant in my experience, but if the root rot is advanced, you may not be able to save it. I’ve found root rot is much more common in potted plants, although the ones in the ground aren’t totally immune.

Here’s what you can do to address root rot:

1. Carefully uproot your plant.
2. Brush away the soil and look at the roots- root rot shows up as brown, mushy, stinky root sections.
3. Use sanitized garden shears or pruners to trim those areas away
4. Rinse the roots under running water
5. Replant your parsley with fresh soil. Throw the old soil out- it’s contaminated with microbes.

Avoiding overwatering is definitely preferable. As a fast-growing herb, parsley likes a fair amount of water to keep the soil consistently moist. That’s usually somewhere between 1 and 2 inches per week, depending on the size/maturity of the plant and the weather conditions.

Typically, this means you’ll have to water your parsley deeply once to three times every week. Use the finger test to figure out if your parsley needs water- if the soil feels dry 1 inch deep, it’s time for a drink.

2. Under-Watering

Under-watering is the flip side of the issue we just talked about, and it can happen from either not watering frequently enough or not giving enough water at a time.

When a plant is chronically under-watered, the roots begin to desiccate, or dry up, and they can no longer soak up water to deliver to the rest of the plant. To conserve resources for the younger, new growth, the plant often cuts off energy to the older leaves, so they turn yellow.

Here again, feel the soil. If it feels dried out and crumbles in your hand, your plant needs water.

Typically, though, leaf yellowing in an under-watered plant is a late sign that you have a problem. All-over wilting and drooping almost always show up first, with the plant sacrificing leaves only as a last resort.

How to Fix Under-Watering

Give your parsley some water right away.

• If your plant is in a pot, give enough water so that the excess flows freely from the pot’s drainage holes.
• If your plant is in the ground, water long enough to thoroughly drench the soil.

If you catch an under-watering problem early, a single good watering can rehydrate your plant. But if the problem is more advanced, check your plant again in a few hours. If the soil feels dry an inch or two deep, water again.

Once you’ve got your plant back on track, follow the watering tips I shared above to keep your parsley properly hydrated.

3. Nutrient Deficiencies

Nutrients, primarily nitrogen, give our plants their lovely green color. And when those nutrients aren’t readily available for your parsley, some leaves can lose the green and turn a sickly shade of yellow.

Suspect a nutrient deficiency if you can’t remember the last time you fertilized. You can also find out your soil’s nutrient levels with a soil test kit.

How to Fix Nutrient Deficiencies

Make sure to plant your parsley in rich, nutrient-dense soil and give your plant regular doses of supplemental fertilizer throughout the growing season.

Compost is always the top choice for fertilizer, both for topdressing to enrich the soil before planting and for regular side dressing. This video from Dave the Hillside Gardener does a nice job of showing the difference between top and side dressing:

If I’m between batches of compost being ready to apply to my plants, I like to use an organic vegetable/herb fertilizer- Dr. Earth Home Grown is my favorite formula. Whichever fertilizer you choose, follow the package directions for the application process and frequency.

4. Not Enough Sunlight

Chlorophyll contains green pigments that play a key part in the plant’s food-production system, photosynthesis. When plants aren’t exposed to enough sunlight, chlorophyll production goes down, leaving plants with weak, yellow-tinged leaves.

Side note: Yellow isn’t the only unhealthy color parsley can turn if not given the proper sunlight. Find out what to do if you find white spots on parsley.

Sun-starved plants will also grow slowly or not at all.

Parsley is a sun-lover and does best when it gets at least 6 hours of light each day.

How to Fix Lack of Sunlight

If your parsley is in a container, move it to a spot that gets more light exposure. This could also be as simple as turning your pot if you’re growing your parsley with other plants that could be creating shade. It’s an easy fix, but it’s really easy to overlook- it’s happened to me before!

If your parsley is in the ground, make sure there are no taller garden plants or neighboring shrubs/bushes making things too shady. Trim back any plants you can if this is the case.

Sometimes permanent objects, like trees or buildings, create shade. If that’s the case, you may have to transplant your parsley- or make a note to plan your parsley patch in a sunnier area next year.

5. Normal Aging

This is one of the more common reasons I’ve found for yellowing in my parsley. And fortunately, it’s nothing to worry about- it’s just part of your parsley’s normal life cycle.

A plant sends the bulk of its energy and nutrients to the new growth on the central stalk- this is how the plant grows and eventually produces seed. As the energy flows to the younger leaves, there’s less to go around for the older ones, so they eventually turn yellow and die off.

In this case, the yellowing should be confined to the oldest leaves at the base of the plant.

How to Fix Normal Aging

When this happens to my parsley, it usually means that I’ve neglected to harvest for a bit too long. The yellow leaves have reached the end of their natural lifespan before I got around to picking and enjoying them while they were still at their peak green stage.

Treatment is easy- just pinch off the spent leaves and throw them in the compost pile. And in the future, make sure you take full advantage of all the goodness your parsley plant has to offer by harvesting more frequently!

6. Root Constriction

Healthy roots are key to your parsley absorbing all the moisture and nutrients it needs from the soil. And if the roots can’t do their job correctly, the plant will start to suffer the effects, often with leaf yellowing.

Root constriction happens most commonly in potted parsley plants when the plant has simply outgrown its home.

It can also happen if you have too many plants packed too closely together. I’ve been guilty of that- it’s so hard to picture these small seedlings you’re planting at their mature size!

How to Fix Root Constriction

If you have a single parsley plant in a container, repot it into one that’s about 2 inches larger in diameter.

If your yellowing parsley is part of a larger mixed pot, you can try to move it into its own pot. But you risk damaging the roots of the neighboring plants in the process.

So you may just have to live with the situation this season and make a note to use a larger pot next year. Frequent harvesting of all your herbs will help keep everybody trimmed down to a better size, and it will help stimulate the plants to produce new green growth.

7. Pests

The University of Florida Extension lists several common garden pests that will take the opportunity to make a meal of your parsley plant, including:

• Aphids
• Cabbage loopers
• Armyworms
• Cutworms

When pests attack, they can drain the plant of vital sap or munch directly on the leaves/stems. Either way, the damage can cause the leaves to turn yellow and die.

How to Fix Pest Attacks

If you need to get rid of aphids, a strong stream of water should knock most of the adults off the plant. Use your garden hose for outdoor plants and the shower for indoor ones. Aphids have a roughly 4-week life cycle from egg to adult, so repeating the spray-down weekly for a month should break the cycle.

For cabbage loopers and armyworms, insecticidal soap can help get rid of existing pests.

For cutworms, pick off the caterpillars by hand and dispose of them in a cup of soapy water, then spread a layer of diatomaceous earth (DE) around your plants. DE is made of sharp, microscopic crystals that slice into the cutworms’ soft bodies, killing them. Check your parsley plant often for the next few days, picking off any other cutworms you find. Reapply the DE after rain or watering.

NOTE: DE is a known lung irritant, so wear a mask while working with it, and don’t dump large amounts of it at once to avoid making a dust cloud.

To keep pests to a minimum in the future, plant flowers that attract beneficial predatory insects to your garden. Marigolds, nasturtiums, cosmos, coneflowers, sweet alyssum and clover are some good options.

Final Thoughts

Parsley is a tasty, healthy addition to the garden- so don’t let a few yellowing leaves stand in the way of your harvest! I’ve found that even if my parsley suffers a setback, it’s eager to go back into production mode once I identify and correct the problem.

I hope these tips are useful for you and your parsley this year. If you have any more questions or any parsley-growing tips you’ve picked up along the way, I’d love to hear about them in the comments. I believe learning from each other is the best way to gain knowledge, so please feel free to share!