With its red color strawberries are attractive and delicious, but it might be worrying if strawberry leaves turn red.
Cornell college of Agriculture and Life Sciences, states two major causes of this discoloration. One being leaf scorch diseases and other is due to deficiency in nutrients.
Apart from this, there can be several factors that turn green strawberry leaves to red or purple.
Soil pH, fungal diseases, cold climatic conditions, phosphorus and nitrogen deficiency can turn strawberry plant leaves to red.
So, now the question arises how to revive your plant and how can you avoid leaf discoloration in this fruit plant?
Before jumping to its causes, allow me to write few points of nutritional requirement of strawberry plant.
Essential Nutrients to Grow Strawberry Plant
How many nutrients a strawberry plant need depends on soil type, growing season, nutrients in the soil and crop history.
Like most plants, strawberry needs balanced amount of NPK ratio while planting.
Along with fertilization, you should add organic matter around the plant to achieve fertile soil.
Growing soil has lots of nutrients, which your plant will need all the time. But, during growing phases, strawberry needs certain nutrients in large amount.
Most reputed and essential nutrients include nitrogen, phosphorus and potassium. Apart from this, calcium, zinc, boron, iron, magnesium, copper, sulfur and silica are need to grow healthy strawberry plant.
Every nutrient has its own important role in growing successful strawberries.
- Nitrogen is responsible for green leaves of your strawberry plant.
- Phosphorus is needed for photosynthesis process.
- Potassium looks after regulating the use of water and to fight diseases.
- Similarly, calcium to resist mold, iron for chlorophyll production, sulfur to ripe strawberries.
Clearly, deficiency in these nutrients will eventually result in discoloration of leaves and your plant will be prone to disease.
Strawberry Leaves Turning Red: What Causes?
If you haven’t skipped above lines, then you might already know importance of soil nutrients.
But, why strawberry leaves are turning red?
As already mentioned, it can be due to deficiency in nitrogen and phosphorus or it plant disease like leaf scorch turned your green strawberry leaves to red.
1. Nutritional Deficiency
Agricultural University states, when the soil lacks enough nitrogen or phosphorus, strawberry plant leaves turn purple or reddish in color.
To avoid, you must initially soil test before growing strawberry plants.
Why Nitrogen or Phosphorus deficiency occurs?
Nitrogen plays vital role in chlorophyll production, which is essential in photosynthesis.
- Deficiency in nitrogen occurs due to leaching. Loss of nutrients due to heavy rain or excess irrigation.
- Lack of moisture in the soil makes it difficult for plant roots to absorb water soluble nutrients by roots.
- Poor soil aeration also results in deficiency in nitrogen.
- Soil temperature, weed infestation, root health, low organic matter in the soil and soil salinity all can cause nitrogen deficiency in your growing soil.
- Phosphorus deficiency can be found in soil that has too high pH or too low pH.
You should opt for neutral soil pH.
If the soil pH is less than 7.5, adding soil amendment like sulfur will help to neutral soil pH.
In case, soil pH is above 7.5 then it can be difficult to lower. Gardeners must opt for pH tolerant plants in such soil. Read more about reducing soil pH here.
Excess carbon can turn strawberry leaves red
Presence of too much carbon in the growing soil can affect decomposition of organic matter.
Microorganisms work for your plant to break these carbon compounds needs more nitrogen and as a result it uses N from the plant.
Thus, resulting in nitrogen deficiency and turning green leaves to red.
You can avoid it by keeping sawdust, straw and pine needles.
Conduct soil test before adding organic matter or fertilizers to get rid of nutrient deficiency. You can use bone meal or worm castings that are high in nitrogen.
2. Climatic Conditions
Most plants undergo dormant stage during winter. Similarly, if you see strawberry leaves turning red in cold temperature, then don’t fertilize instead leave it so till winter goes.
3. Leaf Scorch
Inspecting your plant leaves is a major step to determine the fungal infection like leaf scorch.
If you notice, purple lesion on leaves along with red leaves, then most likely it is leaf scorch disease.
If ignored, it can spread to fruit and eventually kill the plant.
Depending on the variety of plant, you might notice different signs of leaf scorch.
Common symptoms: Reddish purple spots on leaves and stems. It can also spread to runners and fruit.
This fungal disease spread rapidly in wet or moist environment. Avoid overwatering your strawberry plant.
Cut the affected part of the plant and use fungicide to resist fungal spread.
Avoid using such affected plant leaves in your compost bin.
Here is a research publication that explains how soil pH affects nutritional availability in the growing soil.
Gardeners must test their soil before starting strawberry plants.
- Your strawberry plant prefers slightly acidic soil with pH 5.3 to 6.5. (Source)
- Add lime if pH is less than 5.3.
- If the soil pH is too high, add elemental sulfur before 1 year of planting.
How Avoid Strawberry Leaves from Turning Red?
In simple points:
- Soil test before planting. This will help to reduce or increase pH of the growing medium.
- Also, conducting soil test for nutrients will help you to add essential nutrients before planting strawberry plant.
- Avoid overwatering.
- Ensure the plant gets enough sunlight.
- Growing medium should be have enough organic matter that releases water soluble nutrients into the soil.
- Inspect your strawberry plant leaves regularly. If noticed fungal infestation, then cut the affected part and use fungicide.
- Avoid using tools that are affected by plant disease.
Growing medium, watering and sunlight exposure all are important for plant growth.
Before planting strawberry ensure to conduct soil test to determine nutritional ability.
Essential nutrients like nitrogen, phosphorus and potassium are essential for a healthy strawberry plant.
Though you provided enough nutrients, what happens when the plant roots fail to absorb them?
Nutrients like nitrogen prefer neutral soil pH, with too high soil pH nutrient may find it difficult.
As mentioned above, soil pH will affect nutrients in the soil. It can be organic or synthetic fertilizer.
Start to fertilize your plant with balanced NPK. Then you can add nitrogen rich fertilizer to boost leaf, roots and plant growth.
Home gardeners along with growing soil, add old compost to container. Along with NPK, compost attracts helpful fungi that bring other nutrients to the growing medium.
You can also use liquid fertilizers, as strawberry leaves can absorb nutrients.
Like most plants, strawberry plant absorbs nutrients from its growing medium. So, you should opt for well-drained and fertile soil.
Should I be worried about strawberry plant leaves turning red?
No, you don’t have to worry.
First diagnose the root cause.
Use fungicide if the cause if leaf scorch.
Else, add nitrogen or phosphorus rich fertilizers to the growing soil.
Why my strawberry stems and leaves are are turning red?
Nutritional deficiency, leaf scorch plant diseases can cause your strawberry stems and leaves to turn purple-reddish.
Should I prune red strawberry leaves?
Yes, leaves turning red or purple can either affected by fungal disease or the soil has nitrogen deficiency. Trim and add required amount of nutrients to the plant.
Can overwatering strawberry cause red stems or leaves?
Yes. Fungal infestation grows rapidly in wet moist environment. Avoid excess watering your strawberry plant.
What deficiency causes red stem?
Phosphorus and nitrogen deficiency causes red stem and leaves in strawberry plants.
Strawberry leaves turn red or purple due to deficiency in nitrogen and phosphorus.
As mentioned, leaf scorch can result in purple lesion on strawberry leaves, stem and fruit.
You need to diagnose the problem, only then apply nutrients, as high amount of nutrients can often result in stunted plant growth.