Last year, we grew strawberry plants, but they ended up getting brown leaves and dying. This year, we wanted to apply what we’ve learned and help our strawberry plants thrive. Here’s what we learned about brown leaves on strawberry plants.
Strawberry plants get brown leaves due to improper watering, nutrient deficiencies, pests, diseases, or sunburn. To fix this, maintain proper watering, provide balanced fertilization, monitor for pests and diseases, and protect plants from excessive sun exposure.
While strawberries get brown leaves for several reasons, how can we tell which issue is causing it, and from there—how can we fix it? Let’s take a closer look.
1. Improper Watering
Under-watering strawberry plants cause their roots to dry and die, which limits the amount of moisture the plant can send to its leaves. As a result, the leaves curl, brown, and drop. If left for too long, the strawberry plant will die.
While it’s difficult to tell the exact amount you should water strawberry plants, there is a good rule of thumb.
Only water strawberry plants when the first 2-4 inches of soil is dry.
Since each plant has different soil, sunlight, wind, drainage, and other factors, it’s impossible to provide a set volume of water.
However, by checking the soil first, you’re ensuring you’re not under-watering.
If you find that your strawberry plant’s soil is drying too fast (usually within 1-2 days of watering), there are a couple of things you can do:
Soil likes to be covered, and providing compost and mulch is the best way. Covering the ground allows the soil (and its beneficial microbes) to escape the drying effects of sun and wind. It also prevents soil erosion.
Apply 2 inches of compost and 4-12 inches of mulch to the top of the soil.
Compost and mulch also dramatically improve the soil’s water retention, nutrients, and health. As a result, you don’t have to water (or fertilize) your strawberry plants nearly as often.
Providing compost and mulch mimics forests: fallen branches, leaves, and animal manure build the soil.
However, there are times when adding mulch is not a good idea.
Excess watering drowns the roots of the strawberry plant, leading to issues such as poor soil aeration and fungal growth (such as root rot). If not addressed, the strawberry plant develops yellow, brown, and dropping leaves.
Eventually, the strawberry plant will die.
If you check your strawberry plant’s soil and notice it’s sopping wet for 1+ days, it likely has poor drainage.
Check your soil’s drainage by pushing a finger 2-4 inches into the soil. If it’s bone dry, increase your watering schedule. If it’s sopping wet, hold off on watering until it’s dry.
While the above is a good way to get a quick reading of your soil’s drainage, there’s a more extensive method.
Here’s how to do a drainage (percolation) test:
- Dig a 12-inch by 12-inch hole
- Place a yardstick in it and fill it with water
- Measure the drainage over 1 hour
Good soil drainage is around 2 inches of drainage per hour. Any more and the soil is draining too fast, any less and it’s draining poorly.
Don’t worry if yours is way off, this is a guideline and not a rule. We have some areas with soil drainage of 5 inches per hour and plants still grow well.
If your soil is draining too quickly, increase its richness with compost and mulch. This encourages more organic matter and soil life (which holds more moisture). It also reduces the soil’s water content from evaporating.
If your soil is draining too slowly, you’ll also want to increase its richness. This is because the organic matter in the soil not only retains water but breaks up the larger clumps of soil—allowing for ideal drainage. However, avoid mulching your strawberry plants as it can trap moisture, preventing evaporation.
2. Improper Nutrients
Either too much or too little nutrients cause strawberry plants to get brown leaves. Excess nutrients chemically burn the plant’s roots, causing the plant to die off. Too few nutrients starve the plant.
Feed your strawberry plant a balanced fertilizer (such as a 10-10-10) as directed, or 2 inches of compost every 1-2 months. While chemical fertilizers have short-term benefits, they have been found to harm the soil long-term (and therefore the plant).
Because of this, I prefer to use compost and mulch. However, chemical fertilizer can be handy in the short-term.
As with all plants, strawberry plants have three primary nutrients: nitrogen, phosphorus, and potassium (abbreviated as NPK). Both chemical fertilizers and compost have sufficient nutrients for strawberry plants.
If you’d like to buy fertilizer, I recommend the brand Down to Earth. You can see more on my recommended fertilizer page.
You can also make your own strawberry plant fertilizer at home. Here’s a table I put together of the primary nutrients along with the ingredients you can use:
|Coffee grounds, feathers, blood meal
|Bone meal, gelatin, leaves
|Banana peels, sweet potatoes, mushrooms
|Kelp, beans, spinach
|Eggshells, bonemeal, molasses
To see my complete list of food scrap ingredients and example combinations, check my post on homemade fruit tree fertilizer.
A strawberry plant could have all the nutrients it requires, but if the soil pH isn’t balanced, the plant won’t be able to absorb them.
This is because a slight acidity dissolves the nutrient solids in the soil and makes them accessible to the plant’s finer roots.
As with most plants, strawberry plants prefer a slightly acidic soil pH (5.3-6.5).
Fourteen of the seventeen essential plant nutrients are obtained from the soil. Before a nutrient can be used by plants it must be dissolved in the soil solution. Most minerals and nutrients are more soluble or available in acid soils than in neutral or slightly alkaline soils.Donald Bickelhaupt, SUNY College of Environmental Science and Forestry
The best ways to check your soil’s pH are with pH strips or a meter. I prefer using a pH meter since they’re easy to use and affordable. To see which pH meter I use and recommend, check out my recommended tools page.
If you find your strawberry plant’s soil pH is too acidic (below 5.3), apply alkaline amendments such as wood ash, biochar, or lime.
For soil that’s too alkaline (above 6.5), apply acidic amendments such as sand, peat moss, and coffee grounds.
Protecting your strawberry plants from excessive sun exposure is essential for their overall health, as sunburn can cause leaves to turn brown and dry. Here are some strategies I’ve found helpful in protecting my own strawberry plants from sunburn and heat stress.
- Provide Shade: One of the simplest ways to protect your strawberry plants from sunburn is by providing shade during the hottest part of the day. You can use shade cloth, which is specifically designed for this purpose, or even repurpose old sheets or lightweight fabric. Make sure the material you choose provides 30-50% shade, allowing enough sunlight for photosynthesis while protecting the plants from excessive heat. Install the shading material on a structure or support system above your plants, ensuring proper airflow.
- Plant in a Suitable Location: Planting your strawberries in a spot that receives morning sun and afternoon shade is ideal, as the morning sun is less intense and less likely to cause sunburn. If you’re planting strawberries in containers, you can easily move them to a shadier spot during the hottest part of the day.
- Mulching: Applying a 2+ inch layer of organic mulch around your strawberry plants helps to keep the soil temperature cooler and retain moisture. This helps protect the plants from heat stress and reduce the risk of sunburn. Some effective mulches include straw, wood chips, or shredded leaves. Make sure to leave a small gap around the base of each plant to prevent fungal diseases from developing due to excessive moisture.
- Adequate Watering: Keeping your strawberry plants well-watered is crucial for preventing sunburn, as well-hydrated plants can better tolerate high temperatures. Water your plants early in the morning, so the moisture has time to reach the roots before the sun gets too strong. Make sure to water deeply and consistently, as shallow and infrequent watering can stress your plants and make them more susceptible to sunburn.
- Use Companion Plants: Planting sun-tolerant companion plants around your strawberries can help provide natural shade and protect them from excessive sun exposure. Some great companion plants for strawberries include taller, sun-loving herbs like basil, dill, or cilantro. These plants can create a microclimate that offers some relief from the intense sun while also providing additional benefits such as attracting pollinators and repelling pests.
4. Transplant Shock
If your strawberry plant was recently planted or repotted, and its leaves are starting to curl, yellow, or brown, it’s likely due to transplant shock. Transplant shock occurs when a plant is exposed to a new environment and has to establish a new root system.
Avoid transplanting strawberry plants unless necessary as it can take up to 1 year for recovery.
To help avoid transplant shock, I like to plant with the following steps in mind:
- Have the new ground (or pot) prepared
- Remove as much of the plant’s current topsoil as possible, without damaging the shallow roots
- Grab the base of the plant’s stem and wiggle lightly
- Using your other hand, scoop up and support the rootball
- Lightly place the plant in the new ground (or pot) and fill it in
- Make sure the soil is at the same level on the plant as before
- Apply 2 inches of compost and 4-12 inches of mulch to the top of the soil
- Water generously and add more soil as needed
Aphids are tiny insects that feed on plant sap, and they can cause leaves to curl, yellow, and eventually turn brown.
To control aphids, I recommend releasing ladybugs or using a homemade garlic or soap spray.
Also, you can use a jet of water to blast the aphids off (this worked for my lime tree and the aphids have yet to return).
Spider mites are another common pest that can cause browning leaves on your strawberry plants. They are tiny and hard to see, but you may notice webbing on the leaves.
To control spider mites, spray the leaves with water to knock them off or use neem oil, which is a natural insecticide. Make sure to apply the neem oil early in the morning or late in the afternoon to avoid harming beneficial insects.
Ladybugs also help keep spider mite populations in control.
Verticillium wilt is a fungal disease that can cause the leaves of strawberry plants to wilt, turn yellow, and then become brown. This disease is particularly damaging because it can persist in the soil for years.
To prevent verticillium wilt, plant resistant varieties, rotate crops, and avoid over-watering (following the tips earlier in this post). If you suspect verticillium wilt, remove and dispose of infected plants to prevent the disease from spreading.
Another fungal disease that can cause brown leaves on your strawberry plants is leaf blight. This disease appears as small, irregular brown spots that can enlarge and merge, causing the entire leaf to turn brown.
To prevent and manage leaf blight, avoid overhead watering, maintain proper plant spacing for air circulation, and remove and dispose of infected leaves. If the problem persists, you can use a copper-based fungicide, which is an organic solution to control fungal diseases.
Botrytis (Gray Mold)
Botrytis, also known as gray mold, is a fungal disease that can cause brown spots on strawberry leaves and fruit.
To prevent and manage botrytis, ensure proper air circulation around your plants, remove any infected plant material, and avoid over-fertilizing with nitrogen.
If necessary, you can use a biofungicide like Bacillus subtilis, which is an organic option.
While our strawberry plants had brown leaves and didn’t do so well last year, we suspect it was a result of poor drainage and nutrients. So, when we planted new strawberries just a couple of weeks ago, we went all out.
We use a combination of Hugelkultur and companion planting (planting chamomile, marigolds, and thyme with our strawberries), and man, they’re really taking off this year!
We’re also using worm tea from our homemade vermicompost bin (see video below). Fingers crossed they continue to do well. I’ll keep you updated!