Not just coleus, every plant needs sufficient light for survival.
If you are wondering how much light a coleus plant needs, this is the only article you need to read.
We will be covering everything related to coleus light requirements including what happens when a coleus plant gets too much or too little light.
So, let’s get started.
Coleus Light Requirements
On average coleus plants perform best in partial shade to full sun depending on the variety and other conditions. Based on scientific experiments, varieties having darker foliage do well in the direct sun while lighter varieties thrive in partial shade.
Here are some of the coleus varieties that thrive in partial shades,
- Coleus Albama
- Coleus Watermelon
- Coleus Rustic Orange
- Coleus Chocolate Cherry
- Coleus Chaotiuc Rose
- Cileus Painted Lady
Now, let’s check out some of the varieties that prefer full sun or direct sunlight.
- Coleus Redhead
- Coleus Inferno
- Black Dragon Coleus
- Coleus French Quarter
- Coleus Henna
- Wasabi Coleus
- Coleus ColorBlaze
- Coleus Red Carpet
If you are not sure whether the lighting for your coleus is right or not, check out the next sections where we discuss the signs of too much light and too little light.
Signs Of Coleus Getting Too Much Light
When a coleus plant receives too much light, the plant will show symptoms like washed out or bleached leaves, changes in variegation, always dry soil, slow or stunted growth, leaves curling upwards, wilting, etc. These signs are common for many other coleus problems, so read the below details to check whether it’s due to sunlight or not.
1. Yellow & brown leaves
Discoloration in leaves is the number one sign of many plant problems including coleus receiving too much light.
In this case, depending on the coleus variety, the bright color foliage starts to fade and showcase a yellowish tint. Even the yellow-colored coleus variety shows the same symptom, but the color change will be very subtle and you might have to look out for other signs.
After a couple of weeks, the leaves start to develop small dark yellow patches and spots. Then these spots will completely turn brown and dry. This is called sunburn in coleus leaves.
2. Leaves curling and wilting
Leaves curling and wilting are another common sign that many other coleus problems exhibit.
When your coleus gets too much light, the transpiration process in leaves speeds up and as a result, the plant starts to lose water content very fast. This triggers the leaves to move away from the light source and as a result, the leaves start to curl.
Even though curly leaves are a common sign, if the leaves are curling downwards, then you can be pretty sure that light is the culprit.
Additionally, if your coleus leaves are wilting during the hottest time of the day, it is 100% sure that the plant is getting too much light.
4. No growth
Coleus plants won’t grow for a few weeks whenever it experiences severe stress.
Receiving too much light will severely damage plant cells that are responsible for transpiration, photosynthesis, and other processes. When these cells are dead, it results in a severe imbalance inside the plant and triggers severe stress for the roots which results in dormancy or very slow growth.
Not just when the coleus gets too much light, stunted growth due to stress can also happen when the plant gets too little light, too much water, repotting, pruning, etc.
5. Dry soil
If you are growing a coleus plant, you may already have a regular watering schedule based on the external climatic conditions.
If you notice that the soil is getting too dry much before the usual watering cycle, then there is a high probability that the coleus is receiving too much light. It is a known fact that too much light will dry up the soil very quickly due to evaporation.
Just like all other symptoms we’ve discussed so far, this sign can also be associated with many other problems including usage of wrong potting soil, underwatering, etc.
But if everything else is perfect and still soil is drying very quickly, the light needs to be checked.
Signs Of Coleus getting Too Little Light
If your coleus plant is getting too little light, the first symptom to check for is the fading of the bright color in leaves and making the variegation less vibrant. Other signs include plants leaning towards the light source, leaves curling upwards, slow and stunted growth, and sometimes too much moisture in the soil.
1. Less vibrant foliage
As we’ve already mentioned above, coleus plants are available in hundreds of different variegations. The pigments responsible for different colors and foliage are generated only when the plant gets the recommended amounts of light intensity.
For example, if your inferno coleus (bright orange variegation) gets very little light, the leaves will have less orange pigmentation and more green color.
2. Plant leaning towards the light source
It is a known factor that plants grow in the direction of the light source.
The coleus plant’s stem will slant toward the light source when it is not receiving enough illumination.
The plant’s main objective in this scenario will be to get as quickly as possible to the light source so that it can receive the highest intensity of light. This describes a long, week stem with very few leaves. And, it is known as a leggy stem in the gardening world.
3. Leaves curling upwards
We have already seen leaves curling downwards as a symptom of coleus getting too much light. And, here it’s just the exact opposite.
When your coleus gets very little light, the individual leaves try to get close to the light source and as a result, the leaves curl upwards.
4. Too much moisture in the soil
Just like how dry soil is a symptom of too much light, always wet and moist soil is a sign of coleus receiving too little light.
It is because the soil won’t drain as quickly as it should when your plant doesn’t get enough light.
Similar to the case of all other symptoms, damp soil may not be the result of poor lighting alone. Numerous additional factors, such as overwatering, poor pot drainage, old soil, root rot, etc., may also contribute to it. So, before concluding that it is due to low light, you must be sure that the other problems do not exist.
Coleus Light Requirements – Frequently Asked Questions (FAQs)
In this section, we answer some of the most frequently asked questions about coleus light requirements. All these questions were asked by beginners to intermediate gardeners in many gardening threads across the internet.
How much sun does coleus need?
Different coleus varieties have different sun tolerances. On average, the majority of the coleus varieties need medium-intensity sunlight or partial shade for at least 10 to 12 hours. If you have brighter color variants like Coleus Inferno, those plants can sustain even full sun throughout the day in humid conditions.
Can I keep coleus indoors?
Coleus plants are mostly grown in outdoor gardens. But in recent times, many houseplant owners are fascinated by the bright colorful foliage of the coleus and are growing it indoors. If you can provide medium to high-intensity light for 12 to 14 hours indoors, then it will do well inside.
Can coleus grow in full shade?
Even though your coleus plant may survive for a few days to a week in full shade, it won’t grow. Bright light is necessary for the plant to grow and thrive irrespective of its location.
Can coleus grow in fluorescent light?
If you do not have a spot with adequate natural lighting, it is fine to put your coleus under fluorescent grow light. Generally, coleus plants are referred to as solar plants, that love moderate to high-intensity sunlight. However, when you grow them under fluorescent lighting, make sure that the light is very close to the plant and has high intensity. Also, it must be turned on for at least 12 hours a day.
If you are wondering about the best light conditions for the coleus plants, now you know that it depends on the variety you have.
If you are not sure whether your coleus is getting the right amount of light, analyze the plants for the above-mentioned symptoms. If it’s receiving less light, try to move it to a sunnier spot otherwise move it to a shadier spot.
For indoor growers, adding a grow light is also a good choice for all light-related issues.
To back up the information we provide in our articles, the Plantials team only uses high-quality sources published in peer-reviewed university or scientific research journals.
- Coleus Species: Solenostemon Scutellarioides, Review Article From Inventi Journal Via Reasearchgate.
- Effects Of Light Quality On Vegetative Cutting And In Vitro Propagation Of Coleus (Plectranthus Scutellarioides), American Society For Horticultural Science.
- Minimum Daily Light Integral For Growing High-Quality Coleus, American Society For Horticultural Science.
- The Role Of Light On Foliage Colour Development In Coleus, University Of Florida Via Sciencedirect.
- Effects Of Different Levels Of Shade On The Growth And Quality Characters Of Coleus, Department Of Crop Science, Eastern University, Vantharumoolai, Sri Lanka.
- Effects Of Light Quality On The Circadian Rhythm Of Leaf Movement Of A Short-Day-Plant, Plant Physiology, Oxford Academic.
- Combined Effect Of Leaf Chlorophyll And Anthocyanin Content On The Overall Aesthetic Appearance Of Coleus (Plectranthus Scutellarioides (L.) R. Br) Var. ‘velvet Red’ Under Four Different Light Levels, University Of Ruhuna.