Known for its toughness, the ZZ plant is a real rock star. They thrive on a bit of benign neglect, but even this unshakeable plant needs the right water levels to give its best performance.
Given their hardy nature, it’s easy to miss the signs of dehydration caused by under-watering. But never fear! The ZZ plant responds well to treatment, and I’ll help get yours back its best in no time.
ZZ plant is tough enough to endure periods of dryness. But it can’t go without water forever. Regular watering once every week or two, enough to keep the soil moist but not wet, is the best approach.
What Causes a ZZ Plant to Become Dehydrated?
Your ZZ plant is a living thing that uses water to make its food, exhaling and inhaling the air around you. During photosynthesis, sunlight combines water and oxygen to build sugars.
Later it uses those sugars to grow and loses water once more as vapor along with other gases through transpiration.
If your ZZ is dehydrated, it’s probably because the water coming into its pot doesn’t match what it needs to support these two processes.
The average ZZ is such a hardy plant that it takes some time to start showing water stress, so it’s easy to miss them until your plant is really starting to suffer. If you forget to water, it will slow down and die.
That said, there are other factors that come into play. Everything from the season to the position of the plant in your home can contribute to dehydration in your ZZ plant. Let’s take a look at how to spot signs of dehydration, and how to treat your under-watered ZZ plant.
Signs of an Under-watered ZZ Plant
Leaves Turning Yellow
When your ZZ plant is in need of a good drink, its leaves turn yellow. Your plant is marshaling its resources, and leaves that are yellow are being sacrificed to allow the rest of the plant to survive.
Droopy ZZ Plant
Your ZZ plant droops when it is thirsty. I’ve often thought of it a bit in terms of hydraulics – the water inside the vascular system of your plant helps keep it upright. Without that extra support, your plant will sag.
ZZ Plant Has Brown Leaf Tips
Browning is a sign your plant is struggling. The tip of the leaf is the most vulnerable to changing conditions, so any failure to keep your ZZ well-watered will show here. When there is a lack of water the resources can not reach the tips of the leaves, eventually, the leaf tips will turn brown.
Brown or Dry Leaf Edges
Even a healthy green leaf will show signs of damage if there’s not enough water to go around. Your ZZ plant starts to seem crispy and brown, as if the leaves are burnt around their edges, despite otherwise appearing lush and healthy.
ZZ Plant Leaves Wrinkling or Curling
As mentioned above, water in the cells of the ZZ plant plumps out the leaves and gives them their form. Once that water starts to run low, the leaf begins to wrinkle and curl.
If your ZZ plants drop their brown-edged leaves, your plant is severely under-watered. Wild ZZ plants drop leaves to conserve water during droughts, and your indoor ZZ uses this tactic when dehydrated, too.
Dry Brown Spots on Leaves
Like dry brown edges, dry brown spots appearing in the center of your leaves show that the leaf itself is dying for want of a drink. Those dry brown patches are dried out and dead.
Potting Soil is Dry
If your soil is dusty and loose, it’s a pretty conclusive sign that your lovely ZZ needs water. Moisture in the soil provides structure, and as it is lost the potting medium becomes flaky and powdery.
While they are out of sight and often out of mind, brittle roots reflect the important role water has in maintaining a plant’s physical structure. Brittle roots are dried-out roots.
Is My ZZ Over-watered or Under-watered?
Of course, nothing is ever as easy as it seems, and many of the signs of an under-watered ZZ plant are quite similar to that of an over-watered ZZ! Confused? Here’s a table to help you work out which approach your sad ZZ needs to come back from the brink.
|Signs of Under-watered ZZ Plant||Signs of Over-watered ZZ Plant|
|Brown leaf tips||Brown Leaf Tips|
|Wrinkled, curled leaves||Yellowing leaves|
|Gradual drooping or wilting||Softening stems and roots|
|Yellowing leaves||Decomposing roots|
|Crispy leaf edges||Foul smell|
I suggest you check the symptoms that are different – the drooping leaves, the wrinkled and curling leaves, and dry crispiness to the leaf tips and edges.
Identifying the Causes of Under-watering
Everyone makes mistakes, and it’s easy to forget to tend to a well-behaved plant. While they will take a bit of neglect in stride, after a few weeks of misses watering even the most resilient ZZ plant will suffer.
If you’re watering frequently and your soil is still dry as a bone, it’s likely the water is evaporating before your plant can use it.
Wide, flat pots allow water to evaporate readily, and a plant in a warm spot near a heater or a bright window will struggle to get the water to its leaves before the lot evaporates. Warm weather will also play its part.
Water Holding Properties of Soil
Not all potting medium is created the same. A medium that is too sandy or rocky will lose moisture rather than retain it, and some sub-standard mixes will allow everything to flow out the drainage holes before it can soak in.
A Note on Nitrogen Toxicity
ZZ plants are slow growers, and as such don’t need a lot of nitrogen. This nutrient is found in most fertilizers, as it is key to building new foliage.
However, for a slow grower like your ZZ plant, an over-abundance of nitrogen can cause a host of problems that look a lot like under-watering. Curling leaves and browning or burnt leaf edges are signs of nitrogen toxicity.
Luckily the most direct fix for nitrogen toxicity is to flush the pot with a lot of clean water, washing the excess fertilizer from the soil. This conveniently also treats under-watering, so it’s not a bad tactic to use if you are unsure.
How To Revive an Under-watered ZZ Plant.
Thankfully under-watering your ZZ plant is not likely to cause a lot of damage and is easy to treat. Your ZZ is a desert specialist, and it grows from fleshy rhizomes that store water and nutrients very efficiently.
That said, all plants need water, so here are the steps I’ve found that will help you bring your dried-out darling back to a full, lush life.
Remove Severely Damaged Leaves
Damaged leaves should be delicately trimmed away with sharp, clean shears. You can leave green leaves with a little crispiness at the edges or tips, but anything yellowed needs to go. Just chop them off. Your ZZ plant then focuses on regrowth.
Consider Your Soil and Pot
Take a good look at the quality of your soil and your pots. All indoor plants benefit from good drainage, but it’s possible to have too much of a good thing. If your mix is not retaining water and dries quickly, it’s a good idea to re-pot.
Your pot itself may also be part of the problem. Plastic pots are better at retaining water than terracotta or unglazed ceramics. The latter are porous materials, and allow evaporation from deep within the soil.
If you opt to re-pot, I recommend a pot around the same size, with no more than an inch or two difference across than the old one.
Ensure your new pot has one or more drainage holes. Plastic or glazed ceramic is a good choice in terms of materials.
For a potting medium, choose something with a lot of organic matter to provide water retention and structure to the soil. A mix with equal parts soil, peat moss, and perlite will do the trick nicely.
Water From Bottom
Once you’ve done your surgery, if any, and made sure your baby is in the right pot with a good potting medium, it’s time to water.
The most effective way to do this is to water from the bottom. It gets water to the roots and prevents surface evaporation.
- Find a tray or basin large enough to hold your plant with room to move.
- Pop your plant into the tray and fill it with filtered, distilled, or rainwater until the water level reaches halfway up the side of the pot.
- Give your plant time to absorb the water. It will be drawn in through your drainage holes, directly into the roots.
- Add more water as the level in the tray drops. Once the level is stable, wait a few minutes then remove the plant.
Water From Top
Less complicated is watering from the top. It’s how most folk usually water, but as a treatment for under-watering you will need to take a few extra steps.
- Place your plant on an appropriate surface, or in a saucer or tray.
- Fill your watering can or jug with distilled, filtered, or rainwater, and slowly pour it into your plant. Adding water slowly allows it to permeate the soil as it passes into the pot.
- Continue to pour until water starts to drain out the bottom of the pot.
- Allow your plant to rest in the saucer or tray for around ten to fifteen minutes, then remove it and allow any excess to drain before returning it to its home.
Find Good Location for Your ZZ Plant
Bright sun, warm air from heaters, and the breeze of an air conditioner will all cause your ZZ plant to lose moisture. They aren’t charmed by bright lights, so keeping them out of the direct sun will not only keep their soil moist for longer but will help prevent the plant from becoming stressed.
Likewise, draughts or warm air will cause the water in the potting mix to evaporate more readily, so keep your ZZ plant away from vents or draughty corridors.
Set up and Follow Watering Plan
Luckily your ZZ plant is forgiving. Once brought back from the brink it’s pretty straightforward to set up a plan to make sure you remember to water this enduring treasure.
I recommend the busy or the forgetful set a repeating reminder into their phone calendar once every two weeks. That way you don’t need to do the remembering!
Other folks make checking their houseplants part of their weekly routines. You can manually check the moisture level in your ZZ plant’s pot by simply feeling the soil.
Poke around in the mix – it should be allowed to dry to the top inch at least before you even think about watering. I’d even recommend letting it dry out entirely between every other watering. This is a low water specialist, and over-watering causes its own set of issues.
How Often to Water Your ZZ Plant
ZZ plants thrive on a bit of neglect. They are slow growers with low water needs, and even at the peak of the growing season don’t need a lot of water.
In general, once every week or two will do the trick, provided you check your plant and don’t go overboard with the watering can. Here are some extra things to consider when watering your ZZ plant.
Your ZZ plant’s growing season is during the warmth of spring and summer. It uses more water during this time, especially if it flowers in the late summer to early autumn.
Not only that, but the warmer weather will cause any water in its pot to evaporate more readily. It may need more water during this time.
Growth slows during autumn and winter, and less water is needed. Cooler weather will allow any water in the soil to remain there for longer too. I’ve known ZZ plants to go a month at a time between watering in the cooler part of the year.
Most water is lost through the leaves of your plant. A large ZZ plant with thick, abundant foliage will lose more water than a dainty darling with only a few bright leaves to call its own. Larger pots also retain more water, requiring more to reach appropriate levels of moisture.
Temperature and Humidity
Most homes and offices with climate control are kept warm and dry all year round. This causes water loss from both the potting medium and the ZZ plant itself.
A plant in an environment with higher humidity (such as a bathroom) will lose less water than one in a drier, cooler space like a home office.
A ZZ plant is a survivor. They can take quite a bit of punishment before they start to show signs of stress. But if you’ve let your ZZ plant dry out, I have great news – they are easy to revive if you follow my advice.
With a careful eye on water levels in the future, your ZZ will be back to its striking glossy self in no time at all. Simply make sure you get a bit of water to it every week or two, and it’ll give you years of joy.