If the leaves on your philodendron plant turn white, several things could be causing the problem.
Some of these issues are more easily solved than others, but don’t worry – Philodendrons are very forgiving and will soon recover if you provide them with the right conditions.
In this article, I’ll take you through the most likely causes, and a few less common problems.
The most common reason why the leaves of Philodendrons turn white is lack of sunlight, especially in variegated varieties. A white substance on the leaves is likely to be powdery mildew. You need to take a different treatment approach to combat the mentioned problems.
You’ll also find the solutions for each issue, so your Philodendron will be back to its best in no time!
Fungal Diseases
Fungal diseases cause a variety of symptoms, including white patches or spots on the leaves.
Powdery Mildew
If you notice dusty white spots spreading on your plant, usually on the top of the leaf, it’s probably powdery mildew. Philodendron plants love a humid environment. Unfortunately, so does powdery mildew!
This type of fungus thrives in spring and autumn and during summer in cooler areas. Spores form when the air is humid, then disperse when it becomes drier. (Source: Clemson University)
Although powdery mildew is not so dangerous in itself, it can stop leaves from functioning correctly in large amounts. Eventually, this causes weak, slow growth and can even lead to death.
Solution
If you notice a small amount of powdery mildew in your plant, simply remove the affected leaf. If the infection is very bad or spreading quickly, several fungicides are available to treat the problem. Always follow the instructions for the particular brand that you buy.
You can guard against powdery mildew by ensuring enough air circulation around your plants and removing fallen leaves from the plant’s container.
Powdery mildew spores can live for a long time so make sure that you clean plant pots before reusing them, and never reuse infected potting mix without treating it with a fungicide first.
Fusarium Leaf Spot
Fusarium leaf spot usually causes brown spots on the plant’s leaves, which gradually get bigger and spread. They are often surrounded by a yellow ring. In some cases, the spots can be pale, almost whitish color.
Spores spread through the air and land on moisture on the leaves of a plant, then begin to consume the plant and reproduce – causing the symptoms.
Solution
Poor watering technique is a common cause of leaf spot diseases. If you get water on the leaves of your plant, you’re giving the spores a chance to make a home.
If possible, always water your plant from underneath. If you need to water it from above, make sure you don’t get water on the leaves!
If you notice a leaf spot, remove the affected leaves immediately. Use a fungicide developed for fusarium leaf spot, and make sure to follow the instructions.
Pest Infestation
Several types of pests could infect your Philodendron plant. If you see white dots, flies of fuzzy patches on your plant, it could be one of the following:
Mealybugs
Mealybugs are a type of scale insect that feed on the sap of plants. They are usually white and fuzzy or waxy. Nymphs are known as ‘crawlers’ because they crawl until they find a suitable place to feed before transforming into adults.
Adult mealybugs stay in one place, attached to the plant – usually underneath a leaf where it meets the stem. Mealybugs can spread quickly and can be a severe problem for houseplants, so if you see them, treat them straight away.
Solution
First, isolate the affected plant from any other houseplants. If you can see crawlers, spray them with a horticultural soap solution. This doesn’t work on adults because of their waxy shells.
To get rid of adult mealybugs, use a cloth soaked in rubbing alcohol to rub the pests from the plant. Do this several times until none remain.
Whitefly
Whiteflies are tiny, winged insects that feed on the underside of leaves. They can fly, but usually, walk unless disturbed. Their tiny white larvae do not fly. They are not usually a serious problem but will spread to other plants if allowed.
Solution
Treat whitefly with a simple horticultural soap solution, spraying the plant whenever you see them. Horticultural soap is available from garden centers. You can also make your own using warm water and a liquid soap such as Castile soap.
Woolly aphids
Aphids come in many colors, usually green, grey, or brown. They feed on the sap of plants and leave behind a sticky substance called honeydew. Woolly aphids produce a fuzzy white substance for protection.
They can look similar to mealybugs but are much more mobile. You’ll see a tiny black or pinkish dot amongst the white fuzz – this is the aphid itself.
Aphids are not very dangerous in small numbers, but they do spread quickly, so it’s a good idea to treat them as soon as you notice them.
Solution
Like mealybugs, woolly aphids are protected by their waxy coat. The best way to get rid of them is to use a strong jet of water to spray them off your plant. You can also rub them off with a cloth soaked in rubbing alcohol.
Spider mites
Spider mites are often red or brownish, but some are white or almost transparent. They eat through the top layer of leaves and produce white or gray webs, usually underneath leaves near the stem. Spider mites can be a serious problem, destroying plants quickly and spreading easily to other plants.
Solution
Spider mites spread quickly, so first isolate your plant. Luckily spider mites are another soft-bodied pest that you can treat with horticultural soap. Treat them whenever you see them until none are left.
You may want to try an application of neem oil for very bad infestations. This disrupts the reproductive cycle of the pest, so they are less likely to come back in the future. Neem oil lasts a long time, so one application will keep working for a week or two.
Chlorosis
Chlorosis is a condition where a plant cannot make enough chlorophyll in its leaves, causing them to become pale yellow or white.
It can be caused by several factors, most commonly inadequate light, nutrient deficiency, poor drainage, and potting mix that is too alkaline.
Inadequate Light
Philodendrons, particularly variegated varieties, like a lot of bright, indirect light. Without enough light, the plant cannot produce enough chlorophyll, and the leaves become pale and sickly looking. Without enough chlorophyll, the plant can’t make enough food, and growth will slow or even stop altogether.
Solution
For variegated varieties of Philodendron, keep your plant in a bright place with minimal direct sunlight. A position a couple of feet away from a sunny window is ideal.
Non-variegated Philodendrons will be happier in lower light levels. Although they don’t mind bright light, they can thrive in positions that are much too dark for most houseplants, such as shady corners.
If you think that the pale growth on your plant is down to lack of light, move it to a brighter position.
Nutrient Deficiency
Philodendrons are native to tropical areas with rich, fertile soil. When keeping them in pots, it is vital to feed them regularly, or they will develop a nutrient deficiency.
Pale yellow or white foliage in Philodendron plants is often a symptom of calcium or magnesium deficiency.
Solution
Feed your plant with a general-purpose houseplant fertilizer once a month during spring and summer and reduce it to every couple of months in the autumn. Don’t feed it at all during the winter.
Overwatering and Poor Drainage
Although Philodendrons like a moist environment, they don’t like their roots being constantly wet. Wet roots lead to root rot – a serious condition that prevents roots from absorbing nutrients from the soil. In turn, this leads to nutrient deficiencies and results in slow, weak growth that is pale yellow or white.
Solution
Keep your Philodendron plant in a pot with adequate drainage holes in the bottom. If you want to use a decorative planter with no holes, place a few pebbles in the bottom of the planter, then place your plant in a pot with drainage holes on top.
Before watering your plant, check the top few inches of soil. If you can feel any moisture, hold off watering. Never water to a schedule – always check first!
Alkaline Soil
Philodendrons like slightly acidic soil with a pH level of between 5.5 and 6. If the pH level of the soil is higher than this, it can lead to pale, white foliage.
This is because it is more difficult for plants to obtain nutrients from alkaline soil, even though the soil may contain plenty of nutrients.
Solution
Use a pH meter to check the pH level of your plant’s potting mix. If you find that the soil is alkaline (above 7), you can increase the acidity by adding sphagnum peat moss or a special acid fertilizer.
Both are available from garden centers. Always add a little at a time, and follow the instructions if you’re using a pre-made formula.
Other Issues
Excess Salts
If you notice a white residue or granules on your plant’s leaves, it could be down to a process called guttation. This is a natural process where the plant expels water from its leaves to reduce pressure on the cells of the leaf.
It usually happens at night when the temperature drops, but humidity remains high. The water contains various organic and mineral compounds and usually dries to a white residue.
Although guttation is not a problem in itself, if you see a lot of white streaks or granules, it could be a sign of salt build-up in your plant’s container.
Excess salts can cause severe issues like leaf or root burn and become a problem if you use too much fertilizer or rarely re-pot the plant. A white crust on the surface of the potting mix is another sign of mineral salt build-up.
Solution
If you suspect that mineral salts have built up in your plant’s container, re-pot it straight away in a fresh potting mix. Check the roots for damage, and cut out any damaged roots with clean scissors. If you can see build-up around your plant’s roots, gently rinse them in fresh water before re-potting.
To avoid salt build-up in the future, follow these steps:
- Water your plant with rainwater or filtered water if possible
- Re-pot your plant in fresh potting mix once a year in the spring
- Always make sure to dilute fertilizer according to the instructions
Too Much Sun Exposure
If you keep your Philodendron in direct sunlight, such as on a sunny windowsill, it will likely develop sun scorch. The leaves will turn pale yellow or creamy white before becoming dry and brown.
This happens because the delicate cells of the plant’s leaves cannot withstand the intense light and heat from the sun’s rays, and they dry up and die.
Solution
Ensure that you keep your plant in a position that suits your particular type of Philodendron. A good rule of thumb is the more solid green the plant’s leaves are, the less light it needs.
Cold Temperatures
Philodendrons are native to tropical areas and do not like cold temperatures. For your Philodendron to thrive, you should keep it at a temperature of 65 – 85°F (18– 29°C).
If the temperature falls below 32°F (0°C), or even a few degrees above that, your plant could freeze -causing damaged leaves with grey, white or brown spots.
This happens because when the cells of a plant’s leaves freeze, the ice breaks the cell walls, which causes them to collapse once the temperature rises. Once collapsed, the cells can no longer function and die off.
Solution
Always keep your Philodendron plant in a position where the temperature does not drop below 50°F (10°C). Even a cold window could affect the delicate leaves of the plant, so if you keep it near a window, make sure that none of the leaves touch the glass.
Temperature Fluctuation
Philodendron plants are not subject to much change in temperature in their natural environment. If you keep your plant in a place where the temperature changes a lot throughout the day and night, such as close to a window or heat source, it might react badly.
Slow, pale growth, wilting, or curling leaves could be a symptom of problems caused by temperature fluctuation.
Solution
Keep your plant away from drafty windows or other sources of cold and away from radiators or other heat sources. It’s OK if the temperature drops a little at night, but large fluctuations could cause trouble for your plant.
If you want to move your plant to a different position, for example, putting it outside in the summer, it’s best to do this gradually over a few days to avoid causing temperature stress.
Genetic Mutation
Occasionally, plants may produce a leaf or bud that is very different from the rest of the plant. A genetic mutation causes this, and the odd parts are known as ‘sports’. Sports are most common in plant species that have been heavily cultivated – such as Philodendrons.
If your plant has produced a healthy-looking leaf that is entirely white or with a spot that seems to be simply part of the leaf, it could be a sport!
Sports might show characteristics of the variety that the particular cultivar was developed from or completely new features. These sports are no danger to your plant and are often used to create new cultivars.
Solution
There is no way to stop these genetic mutations. If you don’t like the way a sport looks, you can cut it off the plant. There’s no guarantee that the same thing won’t happen again, though!
If your plant’s sport is very unusual, you could try to propagate it to grow more plants like it. You might even end up with a brand-new variety of Philodendron!