I recently added a few strawberry plants to my garden and I noticed their leaves started to yellow. Concerned about what could be causing it, I took to the web to find out more. Unfortunately, there wasn’t much out there, so I did some more digging. Here’s what I found.
Strawberry plants get yellow leaves most commonly from a lack of nutrients, but overwatering, improper growing zone, transplant shock, and pests can also contribute to the issue. For best results, check that your growing zone suits the strawberries and provide them with a quality fertilizer, such as organic compost.
So, while yellow leaves on strawberries most likely result from improper nutrients, what’s the best fertilizer to use and what else can we do to fix them?
1. Lack of Nutrients
Strawberries can get yellow leaves from a lack of nutrients—especially nitrogen. However, phosphorus and potassium are also important for plant health and fruit yields.
Like most plants, strawberries require three main nutrients: nitrogen, phosphorus, and potassium (abbreviated as NPK).
For best results, use a fertilizer that has a balanced NPK or one with slightly higher potassium, such as a 4-3-6 NPK.
A good fertilizer to use for strawberries (especially those with yellow leaves) is Down to Earth’s Acid Mix. It has a good blend of NPK and ingredients and is OMRI-certified organic. You can check out Down to Earth’s Acid Mix on Amazon.
Aside from a quality fertilizer, strawberry plants also need a balanced soil pH. If the soil is too acidic or too alkaline, strawberry plants will be unable to uptake nutrients from the soil, even if you’re using a good fertilizer.
Generally, strawberry plants prefer a slightly acidic soil pH of 5.4-6.5. If your soil pH is currently above or below this, then there’s a good chance your strawberry plant isn’t getting what it needs. This also most likely explains the yellow leaves.
Another common reason strawberry leaves turn yellow is because of iron deficiency. Iron becomes more available as soil pH decreases (Cornell University).
In this case, where your plant has an iron deficiency, your plant’s soil pH is too alkaline (above 6.5), apply acidic amendments such as sand, peat moss, and coffee grounds.
On the other hand, if your soil is too acidic (below 5.5), apply alkaline amendments such as wood ash, biochar, or lime.
A good way to test for soil pH is either with pH strips or a pH meter. I prefer using a pH meter since it’s affordable and easy to use. To see which pH meter I use, you can check out my recommended tools page.
2. Overwatering
Overwatering is another cause of yellow leaves on strawberries. This is especially true for strawberries that have less soil drainage such as those planted in clay soil or in containers.
You can improve the soil’s drainage by drilling more holes in the pot or amending the soil.
To check if your strawberries are overwatered, check the first 2-4 inches of soil with a finger. If the soil is sopping wet, and it’s been longer than an hour since you’ve watered it, then the drainage needs to be improved.
On the other hand, if the soil is bone dry, you’ll need to increase the frequency or amount of water. Water only when the soil gets dry.
Aim to water your strawberries every 2 weeks or so, depending on the weather. Again, only water when the soil gets dry.
If you find that your strawberry plant’s soil is drying out too fast, use 1-2 inches of mulch to cover the soil and protect it from the elements. Some good mulches to use for strawberries are leaves, straw, and pine needles.
Soil that is loamy or slightly sandy is better draining (and more acidic) than clay soil. If you do find you have clay or alkaline soil, consider using sand or compost to amend it and lower the pH, making it more suitable for growing strawberries.
For strawberries planted in the ground, you can create more drainage by planting them in mounds or in raised beds.
For strawberries in pots or containers, the best way to promote drainage is by using a container with enough holes and using soil that is loose and rich.
After addressing the soil’s drainage, mulching and amending the soil with compost will significantly improve water retention without causing overwatering.
3. Extreme Temperatures
Strawberries can start to get yellow leaves if the weather is getting too hot or cold—usually above 80ºF or below 60ºF.
Strawberries prefer growing zones 5-8 as perennials, but can often be grown in zones 3-10 as annuals. If it’s too hot or cold, consider bringing your strawberries inside if possible.
Even though strawberries are perennials, many gardeners grow them as annuals to either prevent their runners from growing too much or because of their growing zone.
The sweet spot for growing strawberries is between 60ºF-80ºF. So, if your strawberry plant is exposed to a temperature outside of this, it can start to kill the plant and cause yellow leaves.
For the best information on the window of time to plant your strawberries, you can refer to the image and table below by the USDA and strawberryplants.org.
4. Transplant Shock
While it’s not as common, strawberry plants can also get yellow leaves from transplant shock.
If you’ve recently planted your strawberries, and they’re getting yellow leaves, consider waiting another 2-4 weeks to see if they improve. If not, consider if any of the above issues could be causing it.
Transplant shock occurs when the roots have to get adjusted to new soil and environment. This can take time as the plant needs to establish a new root system.
You can reduce the chance of transplant shock by transplanting when the plant is as young as possible and avoiding any damage to the roots.
You can also minimize the chance of your strawberry plant getting transplant shock by moving the plant in its best growing season when they are most healthy.
5. Pests and Disease
Some pests such as spider mites can cause yellow leaves on strawberry plants. Diseases, especially fungal diseases, can also cause it.
If you see small dots or yellow spots on your strawberry plant’s leaves, then it’s likely a pest or disease that’s causing it. Prune off the diseased leaves and use an organic spray (such as neem oil).
The most common pest that causes yellow leaves on strawberry plants is spider mites, but there are a few others that could potentially cause it.
The best way to tell if a pest is sucking the sap from your strawberry plants is to check the underside of the leaves. If you see small dots then the plant most likely has a pest feeding off of it.
For a list and photos of common pests for strawberry plants, check out this post by the University of Minnesota.
Strawberries can also get fungal diseases if water splashes some soil up onto the leaves. If this happens, any fungus that’s present in the soil can then spread across the leaves.
For best results, prune the diseased leaves and consider using drip irrigation or watering the soil directly (avoiding pouring water on the strawberry leaves).
In either case, prune the infected leaves and use natural solutions such as neem oil or enlist the help of natural predators of the pest (for example, ladybugs eat aphids)!
