ZZ plants will grow new shoots with light green leaves. These young leaves will turn darker over time as they get older. Other causes of light green leaves on ZZ plants include a lack of nitrogen which will eventually turn the leaf yellow, a lack of water or too much sunlight. Too much water can also cause leaves to turn light green as the soil lacks oxygen, grows mold and loses nitrogen.
Light green leaves on new growth is normal and a good sign of a healthy plant. If older leaves are light green this is a problem that you will need to solve.
This article will explore the top causes of light green leaves on ZZ plants and what you need to do to save your plant.
Top 5 Causes of light green leaves on ZZ plants
Here are the top 5 causes of light green leaves on ZZ plants. Check out each one to see if this is the cause for your plants at home. ZZ plants are hardy and can recover quickly if the problem is identified and solved quickly.
1. New growth
The top reason why ZZ plants will have light green leaves is due to new growth. ZZ plants grow new stems from rhizomes which are potato like growths under the soil. They store water and energy and grow new stems with light green leaves.
Over time the light green leaves will turn a darker green color and become shiny on a healthy plant. It will take around 2 months for the stem to grow and the leaves to turn darker. This is a normal process as the plant slowly increases the amount of chlorophyl in the leaf. This is what gives the leaf its green color.
ZZ plants will grow new stems in spring and summer when the weather is warm. Make sure they get a good water every month and feed them with slow release fertilizer at the start of spring and again in fall. This will keep your ZZ plant happy and growing new, healthy stems with light green leaves
2. Not enough nitrogen
A lack of nitrogen can cause mature ZZ leaves to turn light green. The plant needs nitrogen to develop the green chlorophyll in their leaves. When the plant lacks nitrogen, the leaves will start to lighten in color turning light green and then yellow.
A lack of nitrogen in the soil can be caused by overwatering as nitrogen is washed out of the soil. Choosing poor quality potting mix can also cause this problem if it is not topped up with a good quality fertilizer. Regularly fertilizing is ZZ plants is essential to keep their leaves green.
Use a slow release indoor plant fertilizer twice per year in spring and fall. Choose a slow release fertilizer that lasts for around 6 months to keep your plant happy and avoid mature leaves turning light green.
3. Lack of water
A lack of water can cause ZZ plant leaves to turn light green. ZZ plants are drought hardy but still need regular water to thrive. Their large rhizomes will capture and hold water to help the plant survive a dry period, but they still need water.
If you are watering your ZZ plant less than every month then it could be lacking water. Check the soil to see if it is dry below the surface and deep water your plant. Take the inner pot out of the outer pot and water it thoroughly outside or in your sink.
Water across the surface of the plant allowing it to drain through the bottom. Add enough water so the whole soil surface is wet and water is slowly draining through. Leave the pot to drain in your sink for 10 minutes or until it stops dripping before returning it to the outer cache pot or pot tray.
Note: Always remember to clean your sink thoroughly after watering your plants.
4. Too much sunlight
Too much sunlight can cause ZZ plants to turn light green, yellow or develop brown leaf edges. ZZ plans thrive in deep shade with bright indirect sunlight. Too much sun can burn the leaves and cause damage.
Move ZZ plants into a shade position outside or in a spot indoors that is out of direct sunlight. Keep them away form windows to avoid the reflected heat from the glass. You can remove damaged leaves if they have started to turn brown.
You can leave light green or slightly yellowing leaves on the plant to see if they recover. If the problem is caught early the plant can repair small amounts of discoloring over time.
5. Too much water
ZZ plants that are getting too much water can develop light green leaves. Overwatering can wash away nitrogen, remove oxygen from the soil and even cause root and stem rot. Root rot is a fungal growth that will damage the plant roots and will stop it from absorbing the nutrients it needs.
A lack of nutrients or root rot will both cause leaf damage. This will often start with the leaf turning light green, then it will turn yellow or brown as the damage gets worse. Check the soil and if it is constantly damp or growing mold then it is likely to be overwatered.
The best way to save an overwatered ZZ plant is to repot it into new potting soil. This will add back organic matter, oxygen and nitrogen. This will also help to get rid of any mold or fungus growing on the soil or around the pot.
You can shake off the old potting soil to remove as much as you can. Get some good quality potting soil from and repot your plant into a new, clean pot. You can repot it into the same pot that it came out of, just make sure you disinfect it and let it dry to kill off any mold.
For more on how to disinfect plant pots without using bleach, check out my article here: How to disinfect plant pots without bleach | 7 Easy Steps
Light Green Leaves on ZZ Plants (Zanzibar Gem) | Summary
ZZ plants or Zanzibar Gem will develop light green leaves on their new growth stems. This is perfectly normal and the leaves will darken over time. Light green leaves can also be caused by improper watering, too much light or a lack of nitrogen.
To prevent all of these problems, find a position indoors that gets indirect light, water deeply once per month and feed your plant with slow release indoor plant food twice per year.