I kept my freshly brought ZZ plant near the bright window hoping it would benefit from some sunlight, but sadly, the leaves soon started yellowing, curling, and dropping off.
It was not until my horticulturist pal informed me that my beloved ZZ plant leaves are severely dehydrated from intense, direct sunlight.
Not only did it draw water from the leaves, but it also left them exhaustingly sunburnt.
ZZ plants grow best in indirect light for at least 8 hours a day. In the absence of the sun, you can use grow lights with full-spectrum to mimic their natural light requirement.
They make an excellent houseplant that could thrive even in minimal-growing conditions, but too little sunlight can eventually kill the plant.
Here is a guide to help you determine your ZZ plant’s light requirement and how to treat a sunburnt plant.
Table of Contents
- Can ZZ Plants Survive Without Sunlight?
- Signs your ZZ Plant Needs More or Less Light
- How much Light does ZZ Plant Need, Anyway?
- Can ZZ Plant Grow in Low Light?
- How to Grow ZZ Plants with Artificial Light?
- How to Ensure Optimum Light for ZZ Plant?
Can ZZ Plants Survive Without Sunlight?
Most new growers believe that this Instagrammable plant does not require sunlight, but it is not valid.
Like any other plant, the ZZ plant (Zamioculcas) requires adequate sunlight each day to produce food.
Photosynthesis is a chemical process that requires sunlight to convert water and carbon dioxide to sugar and oxygen or produce food and energy.
The lack of appropriate lighting will affect the photosynthesis process and prevent your plant from getting its regular food source.
The lack of lighting will also affect plant cells’ ability to store and materialize the energy of sunlight that gives the plant its green color.
Therefore, keeping them in the dark corners will push back their foliage growth and invite other plant-related diseases.
Even regular watering or fertilizing is unlikely to save your plant as long as it does not receive sunlight.
Certain factors make all the difference between whether your plant is flourishing or merely surviving, and one of these factors is lighting.
Quick Tip: In zones 10 to 12, you can grow them outside in areas with filtered light, as long as it does not dry up their leaves.
Hence, ensure to keep them in a well-lit location in your homes, such as patio, room wall, or balcony that reflects the indirect sunlight onto the objects.
Signs your ZZ Plant Needs More or Less Light
ZZ plants are quite light-sensitive. Thus, you could tell that your plant is getting excess or less sunlight within a few tell-tale signs.
Start with diagnosing these symptoms to determine whether your plant needs more indirect sunlight (longer duration) or you should limit its light intake.
Signs of Light Deprived ZZ Plant
Here are a few signs of a light-deprived ZZ plant.
1. Overstretched Stems
The plant stems all leaning towards the nearest window or door is the clearest sign of a light-deprived plant.
When your ZZ plant is not getting enough light, it will start branching out towards the light source.
Therefore, it becomes evident with slender, overhanging branches on one side of the container compared to a typical plant fanning out on all sides.
ZZ plants reorient their stems to lean closer to a light source to capture more sunlight.
2. Lanky or Leggy Branches
The plant that is deprived of enough sunlight will begin to look leggy.
Known as etiolation, the plant stems become stretched out with not enough foliage (Leaves) or seemingly small leaves and soft and limp stems.
This is a clear sign of a ZZ plant compensating for lack of sunlight.
3. Slowed or Stunted Growth
It is a serious sign of a light-deprived plant because the growth would only stop when it is severely deprived of food.
When you notice that your plant’s growth has significantly slowed or stopped altogether even in the growing season, it is either because of lack of sunlight, temperature, or watering.
In most cases, the lack of sunlight leaves the ZZ plant stunted.
4. Root Rot Problem
A ZZ plant severely deprived of adequate lighting and warm temperature may encounter root rot problems.
Although root rot is primarily caused by poor drainage of damp soil, the lack of lighting and warmth may increase this process, especially after watering the plant.
Prolonged excess to excess watering will deprive the plant roots of air, leading to decay.
5. Falling or Drooping Stalks
ZZ plant stalks may start falling or drooping when severely overwatered, leading to root rot.
The onset of falling stalks may only be present in the plant suffering a severe root rot caused by light problems.
A cold, stressed plant will also start dropping stalks in some cases.
Hence, check for yellowing of the leaves and stalks falling and drooping that may indicate a light stressed ZZ plant.
6. Leaves Turning Pale
One of the tell-tale signs of a severely light-deprived ZZ plant is leaves turning pale.
The lack of sunlight will prevent chlorophyll production in the plant leaves that allows them to turn sunlight into energy through photosynthesis.
Therefore, they require some amount of light to help with photosynthesis to produce food and retain their natural green color.
Signs of Light Saturated ZZ Plant
Here are a few signs of a light-saturated ZZ plant.
1. Browning Tips
The primary indication of the light over-saturated plant is browning and crispy tips.
The ZZ plant stores water in its leaves that is redirected to the stem and roots when it starts drying out.
The leaf tips are the most sensitive part of any plant that reacts to a water deficiency, resulting in the tips turning brown and dying.
Therefore, dried, browning tips are often the primary indication of a plant receiving too much sunlight.
2. Yellowing Leaves
Yellowing of plant leaves may indicate many different problems, especially overwatering and root rot.
If you are sure that you are adequately watering your plant, it could be a sign of a severely dehydrated plant.
When the plant is left outside for a longer time, it will start dropping leaves to prevent transpiration.
However, before the leaves drop, they turn yellow with wrinkled stems.
3. Curling of Leaves
The curling of leaves is typical in a plant that lacks water.
Excess sunlight results in more water loss from the leaves, depleting their water storage.
Although underwatering is the primary reason for curling leaves, plants often exposed to direct sunlight or warm lighting will develop curled and crispy leaves.
It indicates that your plant’s water source is drying up due to excess heat hence; you should move it away from its present location.
4. Leaning Away from Sunlight
In some cases, the excess lighting may cause plants to lean away from the source.
Also known as negative phototropism, the plant’s inability to access excess sunlight will lean the plant too far away.
The plant photoreceptors contain phototropin that makes up a protein and a light-absorbing portion that takes in sunlight.
The excess sunlight intake may affect the plant photoreceptors, causing the plant to lean away from the light source.
However, root or water scarcity problems may also cause plants to lean away; hence, check for arid soil before ruling out this possibility.
5. Droopy Stems
Droopy stems in the ZZ plant may also be caused by overly dry soil from too much lighting, excessive fertilizer, and transplant stress.
When left under an open lighting source, the plant stalks will begin drooping along with yellowing leaves.
The difference between droopy stalks from lack of sunlight and light saturation is the speed of growth with bare stems.
The plant that lacks sunlight will see a slower growth with bare stems.
How much Light does ZZ Plant Need, Anyway?
ZZ Plant originates from the tropical forests of Africa, making it a drought-resistant plant that requires no direct sunlight.
A typical ZZ plant does well in bright to moderate indirect light and requires at least 8-10 hours of Indirect Sunlight every day.
It is not suited for intense, direct sunlight, so keeping them outdoors without any cover is a complete No-No.
ZZ plant requires temperature within 65°F-85°F range (18°C-30°C) to grow and maintain properly. Hence, 8 hours of indirect light will provide the much-needed warmth to the plant.
Moreover, ensure to move the outdoor plants inside the house when the temperature drops below 60°F (15°C) and sunlight become scarce.
Rest assured, with adequate light and proper care, they will gain a healthy stature of 2.5 feet with lush green foliage.
Here is a table describing briefly direct and indirect lighting sources for plants.
|Direct Light||Indirect Light|
|Direct lighting occurs when the light naturally falls over any object.||Indirect lighting pertains to reflection of direct lighting or that falls outside the direct illumination.|
|It provides strong illumination to a specific area.||It provides less strong illumination outside the area of direct illumination.|
|Flowering plants like Lavender, Blanket flower, Cone flower, and Sunflower love direct sunlight||Tropical species of plants enjoy from indirect lighting.|
Can ZZ Plant Grow in Low Light?
A sturdy plant, the ZZ plant tolerates low indirect light, but the growth will be slower than the plant receiving optimum light.
An overly dark spot will also make your plant suffer. Although it may survive for a short period, it will eventually droop and wither.
The plant will spread its weak stems towards the light source; hence, you would see long spaces between each leaf node, making it look lanky.
However, it will likely store the little energy it produces for survival, directly impacting the stem, foliage, and root growth.
Moreover, your plant will fail to produce the rich, green leaves they are known for.
Therefore, they require some amount of light to help with photosynthesis to produce food and retain their natural green color.
If you cannot give them optimum indirect sunlight, ensure to keep them under artificial light (fluorescent grow lights) for a longer time.
How to Grow ZZ Plants with Artificial Light?
Using artificial light is helpful and very common in places that receive less or no sunlight, such as windowless offices, garages, and bathrooms.
A continuous supply of full-spectrum light with the correct bulb temperature ensures that the plant gets lighting equal to daylight.
Artificial light cannot entirely replace sunlight since artificial lights cannot replicate the specific colors of light optimal for plant’s growth.
However, it may serve well to supplement sunlight, especially where sufficient sunlight is unavailable.
You can easily mimic natural daylight by using the correct temperature of artificial light tubes suspended about 10-12 inches above the plant.
ZZ plants grown in low light tend to be spindly and lack green shade.
A similar plant grown in bright, indirect light will be shorter with sturdy branches and large green leaves.
Therefore, you can rely on artificial light like fluorescent grow light bulbs for growing ZZ plants indoors, but beware of using an incandescent light bulb that generates a lot of high heat.
Also, fluorescent, a form of full-spectrum light, provides the full light menu with less heat.
1. Use Right Light Temperature
Growing a plant for vegetation or flower will require light bulbs with varying temperatures.
Most indoor plants require a cool white or daylight shade, especially in the range of 6000K to 6500K, to grow, while a warm white shade, 2700K to 3500K, will induce fruits and flowers.
However, ZZ plants rarely flower, so they do not need light bulbs with varying temperatures.
You can rely on cool white or daylight bulb (6000k-6500k) to provide full-spectrum lighting to your plant.
GlobalNews.CA reports that Fluorescent light is rich in blue and the shorter wavelengths of red light, essential for healthy foliage
2. Use a Right Grow Light
A standard fluorescent bulb with a 6000-65000k range will best grow ZZ plants.
However, if you are confused between different kinds of fluorescent grow lights found in the market, here is a quick guide for you.
a. CFL -Compact fluorescent lamps are regular bulbs that work well as grow lights.
A single bulb will be enough for growing a ZZ plant indoors. Install multiple CFL bulbs if you have a small indoor garden or switch to T5.
A 40-watt fluorescent bulb will be enough to lighten up a ZZ plant indoors.
b. T5 -T5 is a dedicated grow light with a fluorescent hydroponic fixture used specifically as grow light.
You can mainly use T5 to germinate plant seeds or grow and maintain a large set of plants in a single column.
Here are a few recommendations for an artificial grow light.
|VIVOSUN T5 Grow Light Bulbs||Cool and balanced T5 lamps emit a flat blue and violet spectrum at 6500K.|
|Hydrofarm Agrobrite FLC32D||Produces 1800 lumens and 6400K temp. that will last an average of 10,000 hours|
|2-Pack T5 HO Grow Light||Each bulb produces 2500 lumens in a cool white shade perfect for indoor gardens.|
Alternatively, you can use LED bulbs with the same wattage as effective as grow lights.
3. Reconsider Watering
You can control the watering intake of your ZZ plant kept indoors under artificial light.
Because the fluorescent growth light provides a maintained light intensity, you know when the soil will dry up.
Therefore, you would not need to water your indoor ZZ plants more often.
Watering your ZZ plant once every 18-25 days would suffice when grown in a controlled environment.
Moreover, you need not cut back on watering in winter because your plant will be actively growing.
Read our article on how to appropriately water your ZZ plant to prevent overwatering problems.
How to Ensure Optimum Light for ZZ Plant?
Although a low-maintenance houseplant, the ZZ plant requires ample lighting to ensure minimum upkeep throughout the day.
Here is how you can ensure optimum lighting conditions for this magnificent plant.
1. Plant Location
Location is the key to ensuring optimum light for the ZZ plant.
Whether you choose to grow them outdoors or indoors, make sure to place them in a location that receives at least a faint amount of natural sunlight.
This low to medium light-loving plant would suit a north-facing window that receives relatively less direct sunlight.
An understory plant (the plant that grows under shades of large plants) in shaded corners of the house will help mimic their wild habitat.
If grown outdoors, ensure to use a canopy or mesh net that would block a significant amount of direct sunlight from reaching the plant.
2. Light Intensity
Light intensity also refers to brightness produced by the light source.
It may be more relevant to plants grown using artificial lighting.
The impact of light intensity may depend on the distance between a light source and a plant.
When determining the light intensity of your grow light, consider these factors.
|Photosynthetic photon flux (PPF)||It measures how much a bulb per second emits plant-usable light.
ZZ plant requires 50-150 umol PPF to grow effectively.
|Lumens||Lumens measure the light output of any modern light bulb.
ZZ plant requires 60-80 lumens of light bulb to grow effectively.
|Watts||It is relatively easier to measure light output in watts and determine the cost of energy.
ZZ plant requires 10-15 watt of light energy to grow effectively
3. Light Quality and Distance
Maintaining the correct distance between the light source and plant ensures balanced plant growth.
Keeping the ZZ plant closer to the light source may quickly dehydrate the plant.
Ensure to keep at least 12-24 inches between your adult ZZ plant and grow light measuring 10-15 wattage.
If your ZZ plant is younger, consider placing it at least 6-12 inches closer to the light.
The light spectrum used by the plant is called Photosynthetically Active Radiation, composed of red and blue light.
Non-flowering plants like the ZZ plant may require blue light or mixed light to ensure green foliage.
4. Light Duration
Light duration, also known as photoperiod, measures the number of hours of light a plant needs.
It is classified into three categories.
- Short day –Plant requiring 6-8 hours of light each day.
- Long day –Plant requiring 8-14 hours of light each day.
- Day-neutral –plants that are insensitive to day length different
ZZ plant is naturally a long-day plant that requires over eight hours of light each day.
Alternate between indirect sunlight and artificial grow light to ensure the ZZ plant receives an ample amount of light.
ZZ plants are perfect for carefree people who do not wish to spend significant time with their plants.
The ZZ plant does well without enough watering, but it may require ample low light to thrive.
You can start with finding a location that receives indirect sunlight throughout the day and leave your plant there day-long.
Otherwise, you could always rely on artificial grow light to compensate for the lack of sunlight.
Related Article: Are ZZ plants toxic to human and pets?