Leaves that were once a luscious green suddenly turning yellow is never good news. You might need to do some damage control before it is too late. And for that, you need to understand how the yellow spots on leaves occurred first and then employ appropriate solutions.
This guide covers some of the possible causes of yellow spots, both environmental and plant-related diseases, and tips for fixing them to revitalize your plant and avoid similar issues in the future.
Soil is dry and crumbles when you try to shape it into a ball
Older leaves falling off
Brown leaf edges
A key reason for plant leaves turning yellow is underwatering. When plants do not receive enough water, they cannot form leaves, fruits, or flowers well. To fix this, water your plant evenly and thoroughly to saturate the soil.
Your plant might start looking healthier within a few hours or a few days after watering, depending on the plant. On the other hand, if the plant is watered regularly but the leaves are yellow, then the soil might be compacted.
The water will sit on the soil surface or run out quickly through the drainage holes. To get rid of this compacting, you need to aerate the soil and allow water to penetrate more by poking some holes in the soil using a stick.
Mature leaves are brownish-yellow and beginning to wilt and look limp
Black spots and lumps on the stem and leaves of the plant
The soil is wet and muddy
Fungus gnats
If your plant is underwatered, avoid compensating by over-watering, as it is just as harmful. When plants receive more water than they need, they lack oxygen. This results in root damage, manifesting as yellow spots on plant leaves.
To fix this, check the soil before watering. If the soil feels moist or cool, do not water it. And if it does need water, water deeper and less often. And if your planter does not have drainage holes or the soil is too wet, you will want to repot it.
Yellow or brown leaves and steam near the base of the plant
Plant stops producing new growth
Root bound occurs when the roots lack room to expand and grow. This usually happens with potted plants. Left unaddressed, plants will be deprived of food and oxygen, which results in plant death.
To avoid plant death, repot the plant in a bigger pot. You should use a new container that is one to two inches larger in diameter than the old one. Anything bigger will lead to root rot and stress.
Plants are twisting, turning, and reaching for light
Another reason plant leaves turn yellow is when they receive too little sunlight. Without adequate sunlight, the leaves cannot photosynthesize and chlorophyll production stops completely.
This happens when you place your plant in an area with little sunlight or when the plant is thick and bushy, blocking light from reaching the inner and lower leaves.
To fix this, trim some of the leaves and stems to thin out the plant. Also, place the plant in an area with 6-8 hours of sunlight. And remember to provide shade in the afternoon for partial shade plants to avoid scorching.
But the best method is to ensure they do not attack your plant in the first place. To do that, inspect your plants regularly to nip the issue in the bud.
6. Leaf Spots
Common Symptoms:
Spots on leaves of different sizes and shapes
Spots are initially light or yellow but turn brown, black, or tan over time
Spots turn into raised lesions as the disease becomes severe
Leaf spots and pest infestation have similar symptoms. The only difference is you will not notice pests and their eggs with the former. If you do not see any pests after inspection, your plant is infected by fungal or bacterial pathogens.
The three common fungal diseases you should know of are:
1. Curly Top:
Symptoms: Leaves turn upward and yellow, purple-colored veins, premature fruit, and stunted growth.
Treatment: The disease is caused by beet leafhoppers, so try preventative measures. Also, infected parts need to be removed.
Symptoms: Leaves develop brown spots at first. Then, the leaves turn yellow and fall off.
Treatment: Plant different crops every year and use fungicides.
3. Septoria Leaf Spot
Symptoms: Leaves with dark brown circular spots and yellow ring
Treatment: Maintain ideal humidity and temperature. Avoid overhead watering. Rotate crops annually and use fungicides.
7. Lack of Nutrients
Your plants may lack nutrients if there are yellow leaves on plants. You should know what nutrients your plants need and ensure they are getting them in the right amount.
Spindly yellow leaves on new growth, sometimes with pink tints
Stunted plant growth
Treatment: For immediate effects, apply nitrogen-rich fertilizers such as sulfate of ammonia or poultry manure pellets. For a long-term steady supply of nitrogen, mulch with manure-based compost or use coffee grounds.
Potassium Deficiency
Symptoms:
Yellow leaves with brown edges
Poor flowering or fruiting
Mature leaves develop brown spots or yellow-brown veins.
Treatment: Apply fruit and veggie-rich compost or bury citrus peels in the soil.
Phosphorus Deficiency
Symptoms:
Slow growth
Dull yellow spots on plant leaves
Treatment: Apply superphosphate, bone meal, or rock phosphate.
Magnesium Deficiency
Symptoms:
Common on tomatoes, apples, grape vines, raspberries, roses, and rhododendrons
Yellow leaf veins, sometimes with reddish brown tints and early leaf fall
Treatment: In the summer, apply Epsom salts as a foliar feed for immediate effects. For long-term effects, sprinkle calcium-magnesium carbonate into the soil around the roots.
Abundance of branches and leaves with little to no fruit production.
Leaf drop
Fertilizer crust on soil surface
Just because your plant starts flourishing from fertilizers does not mean more is better. So, do not get carried away. Applying the correct amount is the best for your plants.
To fix this, remove fertilizer crust from the soil surface and wilted/burned leaves. As a cautionary practice, conduct a soil test before applying any fertilizer to determine what your soil needs and make a plan.
Transplant shock is a stress in plants that occurs when they are moved from one place to another for growth. Stress happens when the plant root system is disturbed or there is a change in the microenvironment.
The level of transplant shock can be reduced by gentle handling of plants and correct planting depth. Care for the water plants adequately, especially after transplanting them, and ensure they do not suffer from intense heat or pest attacks.
Extreme variation in the pH of soils reduces nutrient collection and results in yellow spots on plant leaves. Plants have optimal pH preferences for the intake of nutrients; otherwise, they suffer deficiency or toxicity.
When the pH is out of balance, test the soil to find the current pH level. Correct the pH with proper soil alteration, for instance, using calcium carbonate to increase the pH or sulfur to decrease the pH. Also, ensure aeration through the soil aeration guide.
Plants are not producing expected fruits and veggies
Your garden is growing moss and weed
Poor soil drainage is one of the common causes of plant leaves turning yellow that needs to be addressed immediately. Such type of soil is unable to allow water to flow throughout the plant to reach the roots.
Adding organic matter - compost will go a long way in improving soil drainage. Also, check that pots have sufficient drainage openings and think about what sorts of soil you may be using. Also, in the case of garden beds, use raised beds or add drainage layers that will eliminate waterlogging and resultant root rot.
Leaves of the plant turn yellow and wither due to age
Yellowing begins from the margins of the leaf margins and moves towards the middle
There is nothing to worry about if yellowing is observed in old leaves while the new ones are still green and healthy. This yellowing comes with age.
You can remove the old or yellowing leaves to maintain the plant’s aesthetic appeal and control the leaves’ natural aging process. Also, ensure the plant gets nutrients and water to encourage new growth from the base.
Final Thoughts
There are different causes of yellow spots on plant leaves and they all need to be addressed properly. It is therefore imperative to find out the cause of this so as to fully address it and promote plant health.
If the problem is because of a lack of nutrients or other factors like pests and diseases, stress, or any other factor, a specific action will bring your plant back to its best form.
It is important to check often, water properly, and apply fertilizers and treatments prudently in order to have healthy foliage. Knowing these causes will assist you in maintaining the health and beauty of your plants so that they continue to be healthy for a long time when you take proper care of them.
