The ZZ plant is a low-maintenance houseplant that has characteristic, upward-pointing, oval-shaped leaves. They are shiny and waxy, sometimes appearing artificial because they are so perfect.
One of the most common problems encountered by ZZ plant owners is browning leaf tips, and the most probable reasons for this are too much sunlight, underwatering, poor water quality, low humidity, lack of nutrients, recent repotting, and pests.
In this article, we will discuss each of these causes and what you can do to resolve them. So, if you are currently experiencing this problem with your own ZZ plant and wish to learn more, just keep reading.
Why are the leaf tips on my ZZ plant turning brown?
Too much sunlight
Whether your ZZ plant is kept indoors or out, overexposure to sunlight can turn its leaf tips brown. Intense light speeds the rate of transpiration and can dry out a leaf in a matter of hours. If the plant is not salvaged in time, it could die.
ZZ plants prefer bright but indirect light, which allows them to perform photosynthesis without the risk of scorching.
Fortunately, the signs of sunburn are easy to spot. If you notice the leaves browning at the tips, wilting and drooping, consider sunlight as a possible culprit.
If you prefer keeping the plant outdoors, place it under a large tree or on your porch so that it is protected from direct sunlight.
If your ZZ plant is indoors, place it next to north- or east-facing window, since these let in gentler light while being in the shade during afternoons when the sun is most intense.
If the only windows in your home let in harsh light, you can diffuse the light’s intensity with a sheer curtain.
Underwatering
The leaves of your ZZ plant will become brown, dry, and crispy at the tips if the plant is dehydrated. Although it will not die if you forget to water it every now and then, consistent underwatering will have a negative impact on its health in the long run.
You need to keep an eye on the moisture levels in the soil to determine when your plant requires watering. You can check this by touching the top two inches of soil with your fingers. If the soil is dry, water the plant, but if it is still damp, wait one or two days and then check again.
If you think the brown leaf tips are due to underwatering, water the plant generously by soaking all of the soil until you see excess water flowing from the pot’s drainage holes.
Sometimes the soil has been dry for so long that the soil’s surface becomes hydrophobic. In that case, it is best to bottom-water your ZZ plant by placing it in a shallow basin filled with three inches of tepid water. Leave it there for 10 to 15 minutes, and the soil will slowly absorb the water through the drainage holes at the bottom of the pot. After 10 to 15 minutes, remove the pot from the basin and leave it on a rack until it stops dripping, before placing it back in its usual spot. Continue to use the bottom-watering method for a few weeks until the plant has made a full recovery.
Overwatering
If your ZZ plant’s brown leaf tips are accompanied by a mushy leaf texture, you might be overwatering it. This is one of the most common causes of plant death because early detection is quite difficult.
ZZ plants do not like growing in soggy soil; they prefer well-draining soil that dries out between waterings. If they are left to stand in waterlogged soil for too long, the risk of root rot increases hugely.
Root rot is a serious disease often caused by bacteria or fungi that attack the weakened roots of an overwatered plant. The pathogens will make the initial rot of the drowned roots more aggressive, helping it to spread through the stems and leaves.
If you suspect root rot, remove the plant from its pot and wash off as much soil as you can from the roots. Inspect the roots for sections that have turned brown or black; these are rotten. Using sterile scissors, cut them off until only healthy, white roots remain.
Lay the pruned plant on a dry surface to let the roots air-dry while you fill a new pot two-thirds of the way with a well-draining potting mix. Then, place the plant in the middle of the pot and cover the roots with more soil as needed.
Place the plant in a spot where it can get lots of bright, indirect light and good air circulation.
If you were able to prune off all the infected roots, your ZZ plant should make a full recovery.
Poor water quality
Your plant’s browning leaf tips could be a result of continuous tap water use. Sodium, chlorine, fluoride, and other minerals can all be present in tap water, and a buildup of these mineral salts in the soil can be a serious problem for many indoor plants.
The salts cause root burn and the damage can affect the plant’s ability to properly absorb water and nutrients from the soil. If the plant’s absorption is defective, it will weaken and wilt and the leaves will turn brown, beginning at the tips.
Refrain from watering your ZZ plant with tap water, and use distilled or rain water instead. If you do not have access to either, collect tap water in a large container and let it stand covered overnight; this way, the minerals will dissipate and make the water safe to use on your houseplants.
Low humidity
ZZ plants thrive in environments with high humidity levels. In fact, the vibrant color of their foliage can be attributed to the abundant moisture in the air of their natural habitat. Many growers forget about the humidity needs of their ZZ plant because they believe the myth that it is drought-resistant.
When the humidity is low around your plant, its rate of transpiration increases and the leaves dry out faster than normal. The plant is likely to lose a significant amount of water compared with the amount it is taking in. If you do not take measures to increase the humidity, it will start to wilt and its leaf tips will turn brown.
To help your plant out, mist its leaves on a regular basis. This combats the browning because it moistens the foliage and the surrounding air, albeit temporarily.
You could also keep the plant in the bathroom or the kitchen because these are the most humid rooms in the house. Alternatively, place the plant’s pot on top of a tray filled with pebbles and water. As the water evaporates, it will moisten the leaves as well as the soil in the pot.
If you have other plants that enjoy high humidity, group them together with your ZZ plant, so that together they can create a microclimate around themselves.
Finally, an easy option is to use a humidifier to automatically regulate the humidity level around your plant.
Lack of nutrients
Plants that do not receive enough nutrients can suffer from malnutrition. Although ZZ plants are not heavy feeders, restricting the nutrients available to them may cause the browning of their leaf tips.
To remain healthy and vibrant, ZZ plants need a combination of macronutrients and micronutrients, and the presence of discoloration or damage to the leaf tips is a possible indication of nutrient deficiencies. The plant may also experience stunted growth.
Fertilize your ZZ plant once a month during its growth period in the spring and summer, and every two months during the fall and winter. Use a balanced houseplant fertilizer diluted to half-strength so that you do not accidentally overfertilize it.
Recent repotting
ZZ plants grow at a slower rate compared with other plants, but they will still outgrow their pots eventually.
When your plant’s pot gets too small for the plant, you will need to repot it, and during this process, it is likely to experience shock and stress. Its foliage will become wilted, droopy, and discolored as a result of this.
Repotting your ZZ plant in the summer is not recommended, as the heat may worsen the browning and wilting symptoms. Rather repot it in the last few weeks of winter, so that it can recover throughout the spring.
Be gentle in handling your plant when you repot it, so as to cause as little physical damage as possible.
It is normal for a repotted plant to look droopy and to have a little browning at the tips in the days following, as it recovers from the transplant stress. It should be fine after a short time in its new pot.
Pests
Scale insects, spider mites, blackflies, whiteflies, thrips, aphids, and vine weevils are all common insects that infest ZZ plants, and they can be difficult to control.
Pests can have a devastating impact on your ZZ plants, so they should be prevented as far as possible. Insects secrete substances that encourage the growth of mold on the leaves, and this mold prevents the plant from completing its photosynthesis cycle. Later, you may notice the leaves drooping, browning and wilting.
Your best strategy is to pay close attention to your plants so that you spot any infestation in its early stages. If you think your plant has pests, take it to a different part of the house to prevent any possible spread to your healthy plants.
You can handpick the insects off the plant or use a strong stream of water from a hose to knock them off.
Alternatively, apply rubbing alcohol or neem oil to the affected areas using a cotton pad or swab. Repeat the process every three days until you are sure that all pests have been eradicated.
Conclusion
The ZZ plant is a low-maintenance houseplant that is easy to grow and care for. This makes it a perfect starter plant for beginner growers. Still, it can suffer some problems, one of the common ones being the browning of its leaf tips. The most common causes of browning ZZ plant leaf tips are too much sunlight, underwatering, poor water quality, low humidity, lack of nutrients, recent repotting, and pests.
The sooner the specific cause can be determined, the faster the treatment and the sooner the plant can recover.
Image: istockphoto.com / Bilal photos