I have been obsessed with kitchen herbs throughout my childhood. Basil has been my favorite herb to grow due to its ease of maintenance. But maintaining the attractive green foliages has proven to be a challenge due to weather climate dynamics.
So, why are my basil leaves turning white? The possible causes are over-fertilization, pest infestation, overwatering, fungal diseases, and direct sunlight exposure. It would be best to identify the exact problem before implementing measures to fix it.
Continue reading this article to find the exact reasons behind the basil leaves turning white and their respective solutions. You’ll also know factors to uphold to ensure your basil plant stays healthy and happy.
Causes and Solutions of Basil Leaves Turning White
Basil leaves are delicate and juicy. These foliage traits make the herb more vulnerable to insect infestation despite providing a better growing environment.
Aphids, red spider mites, thrips, whiteflies, mealybugs, and leafhoppers are the leading culprit to cause white spots on basil leaves.
These tiny insects usually munch on the delicate leaves and inject toxins into the tissues. The nibbled leaves appear as white dots and later turn to black dots.
I recommend the use of insecticidal soap spray to help in eradicating these pests. Remember to thoroughly clean the basil foliages before consuming them.
Basil plants are quite sensitive to cold weather. These herbs only thrive in warm temperatures of about 68 to 80oF (20-27oC). The herb cannot tolerate any temperature below 50oF (10oC).
High temperatures usually alter the physiological activities of the herb. The basil leaves will begin turning yellow, white, and brown.
I recommend growing basil indoors or in a greenhouse where you can regulate the temperature to enhance better growth. Wait for the frost to disappear, and then plant your basil seeds.
Basil downy mildew is a fungal disease that occurs in wet weather or prolonged leaf wetness. It can also occur due to warm and humid conditions.
Peronospora belbahrii is the causative agent. The fungal condition is highly contagious since it spreads through spores by wind and water.
Basil leaves turning yellow is the initial symptom, and over time the white spots develop underside the leaves. The white spots gradually turn into the black lesion with time.
Avoid misting the basil leaves to prevent downy mildew. I recommend the use of fungicides to help in eradication the fungal disease. (Source: Britannica)
Basil plants are vulnerable to fungal infection during the rainy season. The weather condition makes the leaves moist and soggy environment.
A damp condition and leaf wetness promote the growth of white fungus. The fungal disease is characterized by fuzzy white lesions on the leaves.
The white mycelium will concentrate across the leaf surface and hog the basil plant if it remains untreated. The white fungus growth is fatal and can kill your basil plants in no time.
Avoid creating soggy conditions to prevent white fungus growth. Another excellent option is to use fungicides to eliminate the causative agents.
Basil plants are light feeders when compared to other herbs. Too much fertilizer application leads to excess salt accumulation in the potting soil.
The soil later becomes saline with altered pH that no longer supports basil growth. The roots become weaker, and the basil plant health takes a toll.
The damaged roots are unable to absorb water and essential mineral ions. The basil leaves will begin to manifest white spots and later lose their green coloration.
Bacterial Leaf Spot
The high humidity level can be harmful to basil plants. It promotes the growth of pseudomonas cichorii that causes leaf spot disease on basil plants.
The basil leaves turn pale and white across the surface that darkens and turns brown along the edges. You will also notice some streaks on the stems.
If the black spots are left untreated, the basil plant will die. Use fungicides to treat the underlying condition and prevent basil leaves from turning white.
Too Little Sunlight
Basil leaves have green coloration that depends on natural light to carry out photosynthesis and other physiological activities.
Growing basil plants indoor or outdoor under the shade tend to slow the rate of photosynthesis and even transpiration. It makes the basil plant wither, and its leaves turn yellowish.
I recommend relocating the basil plants to regions that receive bright indirect sunlight. The exposure will help to revive the vibrant green foliages.
Inconsistent Watering Habits
Basil plants thrive in moderately moist soil. The moisture helps the herbaceous stems to remain turgid and maintain an upright posture.
Under-watering deprives the basil plants of the ability to maintain an upright posture and manufacture their food. The dehydrated leaf tissues cause whitening and dryness.
Soak the soil until the excess water runs through the drainage holes. Be sure to inspect the soil moisture content before watering to reduce the risk of overwatering.
Inappropriate Soil Quality and Type
Basil plants do best in light and well-draining soil. The potting mix allows air circulation and avails oxygen to the roots throughout the year.
Besides that, basil plants prefer soil with a pH range of 5.5 to 6.5. Inappropriate soil pH makes the nutrients unavailable to basil plants due to leaching.
Insufficient nutrients and mineral ions in the soil are the reason behind basil leaves turning white and yellow. I recommend the addition of organic matter into the potting soil to boost fertility.
Use fertilizer rich in nitrogen to resolve the white or yellow leaf problem. Be sure to dilute the liquid fertilizer and avoid over-feeding the herb.
Frequently Asked Questions
Why Is My Basil Pale?
Pale basil leaves are an indicator of malnutrition. Feed your basil plants with fertilizer rich in nitrogen to facilitate healthier growth. Too much direct sunlight could cause leaves to scorch.
Why Are My Basil Leaves Turning Silver?
Fungal diseases and nutrient deficiency is the leading cause of basil leaves turning silver. Other possible causes are overwatering, pest infestations, and direct sunlight exposure.
How Often Should Basil Be Watered?
Water basil plants every three days during summer and spring to prevent potting soil from drying. Reduce watering frequency in winter to avoid sogginess and root rot problems.
Basil leaves turning white occur due to overwatering, over-fertilization, pest infestations, and fungal diseases. Identification of the exact cause will help to implement appropriate measures.
But basil plants are easy herbs to grow and maintain regardless of your experience. Provide ultimate basil care to combat possible foliage problems.
I hope the information in this article will help you identify and fix the problem causing white spots on basil leaves. Let us know your experience in the comment section.