If you’re a forgetful plant parent, the ZZ plant can be the perfect houseplant for you. This plant is tough as nails, can survive in low-light conditions, and can live without water for quite some time.
But just like everything, this plant has a weakness. A ZZ plant is much more likely to die from overwatering than underwatering. To prevent that from happening, you must acquire a thorough understanding of the ZZ plant’s watering needs.
Learning about things like watering frequency, watering technique, and signs of overwatering will all play a role in making you a responsible plant parent. Therefore, in this detailed guide, I’ll discuss various aspects of watering a ZZ plant, beginning with the most important question:
How Often to Water a ZZ Plant?
Due to the ZZ plant’s unique nature, it doesn’t require watering often. It hails from an arid region that experiences long droughts followed by occasional intense rains.
These conditions have evolved the ZZ plant to store water and nutrients in its rhizomes (potato-like underground structures). When there’s no rain for an extended time, the plant taps into these reserves to stay alive.
But as a houseplant, you probably don’t want to mimic its natural conditions to a tee. To keep its leaves supple and stems upright, you need to water it more frequently than the rains it experiences in its natural habitat.
If you’re looking for a fixed watering schedule, you’ll find many recommendations on the internet. You should steer clear of them. Why?
Each ZZ plant experiences a unique set of circumstances determined by factors such as light, season, humidity, temperature, etc. If your ZZ plant sits in a sunlit garden, it would require more water than a ZZ plant in someone’s dimly-lit office. Therefore, a fixed watering schedule is a recipe for disaster.
I recommend a different approach to keep your ZZ plant healthy and well-watered for years to come. And that is checking the soil. Ideally, the soil should completely dry before you water your ZZ plant.
Testing the soil will help you closely mimic the plant’s natural cycle and protect the roots and rhizomes from staying damp too long. It will also protect the plant from long, dry spells that could kill it. It is the only recommended way to develop a watering schedule perfect for your ZZ plant.
So naturally, the next question is, how do you check the soil?
How to Tell if Your ZZ Plant Needs Water?
The only way to tell if a ZZ plant is thirsty is to check the soil, and there are three ways to do that.
Doing the Finger Test
The finger test is one of the simplest ways to check the soil. Insert your finger in the soil about two inches deep (second finger knuckle). If the soil feels damp or moist, check again after 2-3 days. But if the soil feels crumbly and dry, move on to the bottom of the pot.
Lift the pot and insert the finger 2 inches deep in the drainage hole. If the soil sticks to your finger after you pull it out, it is still moist, and you should check again in a few days.
However, if you feel dry dust sticking to your finger when you pull it out, you can water your ZZ plant.
Using a Skewer to Check the Soil
If you don’t like getting your fingers dirty, use a wooden skewer or a chopstick to check the soil. The stick should be long enough to reach the bottom of the pot.
Push the skewer into the soil until it reaches the bottom, and leave it there for a minute. Pull it out to see if it looks damp and has soil sticking to it. If yes, the soil is still wet. However, if the skewer is dry, you should go ahead and water the plant.
Using a Soil Meter to Check the Soil
If you’re meticulous and strapped for time like me, there’s no better way to check the soil than a soil moisture meter.
These devices are cheap, quick, accurate, and easy to use. All you have to do is turn it on, insert its probes deep into the soil so that they reach the bottom of the pot, and check the reading.
Water the soil if the moisture meter gives you a “dry” reading between 1 and 3, and postpone watering if the reading is between 4 and 7.
How Much and How to Water a ZZ Plant?
Learning the right watering technique is as important as learning how often to water a ZZ plant. Here are some dos and don’ts of watering a ZZ plant.
Should you water deeply once or water little but frequently?
Some people think that watering a plant often but in small amounts is better than giving it a good soak infrequently.
But as we have learned, letting a ZZ plant dry out is essential to mimic its natural cycle, so I highly discourage frequent watering. Also, overwatering is their kryptonite, and they are more likely to die from it than underwatering.
Therefore, I recommend always giving the ZZ plant a deep soak whenever its soil dries.
How Much Water to Give a ZZ Plant?
Like watering frequency, watering amount is subjective depending on your plant’s unique circumstances. In this case too, you’ll find people recommending a fixed number of cups of water, but that’s just bad advice.
I recommend you water the plant deeply until the excess water starts flowing from the drainage holes. It can be 4 cups for someone with a tall ZZ plant in a large pot or 2 cups for someone with a smaller plant.
With that out of the way, here’s the right technique for watering a ZZ plant:
Top Watering—How to Water a ZZ Plant?
Top watering is the recommended method for watering a ZZ plant. Here’s how to do it in a few easy steps:
- Pour the water around the edges and not the center of the plant. Watering close to the leaves can cause waterlogging and affect the plant’s health.
- Ensure the water stream is gentle and slow instead of heavy and fast. Too much pressure from watering can disturb the soil, which you’ll have to pat down later.
- Use room temperature water.
- Water until the soil is soaked, and the excess water starts flowing out of the drainage holes.
- If you keep a tray under the pot, empty it after all the excess water has been collected. Letting the plant sit in the water-filled tray for too long can damage the plant’s roots and rhizomes.
When to Bottom Water a ZZ Plant?
I don’t usually recommend bottom watering, but there are a few instances when bottom watering is more appropriate.
Firstly, ZZ plants can become root-bound. It means that its roots can grow too big and surround the soil inside the pot. When this happens, the water usually flows down the pot without absorbing into the soil.
Secondly, a ZZ plant’s soil can also become compacted. Compaction happens when soil particles are pressed tightly, affecting its porous nature. Fewer pores in soil mean reduced absorption and transfer of water/nutrients to the roots.
In both cases, top watering will not adequately soak the soil. These conditions can only be fixed by moving the plant to a bigger pot (when root-bound) and changing its soil (when soil is compacted). However, you can water your plant through bottom watering until you find the time to fix these issues.
Here’s how to do it in a few easy steps:
Steps to Bottom Water a ZZ Plant
- Fill the pot tray with room temperature water and place the plant in the tray.
- In about 20 minutes, the plant’s soil will absorb the water.
- To check whether the soil has absorbed enough water, insert your finger in the topsoil about two inches deep.
- If the soil feels damp and sticks to your finger when you pull it out, the plant has absorbed the water
- If the tray is empty, but the soil still feels dry, refill the tray and wait for another 20 minutes.
- Check the soil again and empty the tray if the soil has absorbed water.
Should you Use Tap Water or Distilled Water?
Tap water contains higher concentrations of salts and minerals that can accumulate in the soil and affect nutrient uptake. However, when it comes to ZZ plants, it seems to have little adverse effect. Use distilled water if you can acquire it easily. Otherwise, tap water is fine too.
But if you regularly use tap water or bottom-water your plant frequently, it is a good practice to give your plant a water flush every couple of months. Here’s how to do it.
When it is time for watering, top water your plant with distilled water and use three times the water you normally use. As the water flows out of the drainage hole, it will refresh the soil by removing the mineral and salt build up with it.
Watering a ZZ Plant in Summer vs. Winter
With time, you’ll automatically develop a schedule that fits your ZZ plant. But you should know that you must readjust your watering routine as the seasons change.
You see, summer is the active growing season for the ZZ plant. The plant is trying to grow during this time and needs more water and nutrients. Since the temperature is also higher, the soil dries out more quickly during summer. It means you’ll have to water your plant more during summer.
As the winter rolls in, the plant starts entering dormancy. It is the period when the plant is not focused on growing but storing water and nutrients in its rhizomes. As the temperatures drop, the soil also dries out slowly. This leads to the plant requiring fewer watering sessions.
Therefore, it is best to stay vigilant when the season changes and reassess how quickly the soil dries.
Signs of an Overwatered ZZ Plant
A ZZ plant is more likely to suffer from overwatering than underwatering. Here are some key overwatering symptoms to look out for:
The roots of a ZZ plant become waterlogged when they sit in soggy soil for too long. Waterlogging means that the roots cannot absorb the nutrients from the water to keep the plant healthy.
The first sign of this is yellowing leaves and stems. As the nutrient supply is compromised, the leaves and stems become sick and lose their vibrant green color.
Wilting Leaves and Stems
Noticing an occasional drooping leaf or stem is normal.
But if more and more leaves and stems of your ZZ plant are starting to wilt, it is a clear sign of restricted nutrient supply to the plant because of the waterlogged roots.
Leaves Dropping Off
Generally, a ZZ plant drops leaves when it is underwatered and needs to conserve its resources. In this case, the leaves wither and drop off slowly and gradually.
But when a ZZ plant starts dropping off many leaves at once, it is likely overwatered. If the plant drops leaves with other symptoms mentioned above, there should be no doubt that it is being overwatered.
Soft and Mushy Spots
You’ll notice the stems and leaves developing brown, mushy, and soft spots in severe overwatering. These spots originate from the soil line and are a symptom of root rot. Root rot is a disease that affects rhizomes and roots that stay in soggy soil for too long.
Rather than a symptom, root rot is a disease that develops when a ZZ plant experiences overwatering for an extended time. It is a decay that happens when mold starts affecting the roots and rhizomes of an overwatered ZZ plant.
Apart from the symptoms mentioned above, some key indicators of root rot are foul-smelling soil and mushy roots. But to check the roots, you must pull out the plant and observe them closely.
If any symptoms from this list are present, it is better to stop watering immediately and take the plant out of the pot to be sure.
You should also know that in severe cases of root rot, it may be difficult to save the plant. But hopefully, it won’t come to that if you catch the symptoms early on and take prompt action.
Fixing the Problems Caused by Overwatering
The first step to save and revive an overwatered ZZ plant is to stop watering immediately until the soil is thoroughly dry. It could take weeks to months, so be patient.
Next, you should see if the soil mix is appropriate for the ZZ plant. To promote drainage, you should use a high-quality and well-draining potting soil mix with 20-30% perlite.
However, if the plant still doesn’t recover, or if it is clear that the symptoms are severe, it is best to test the plant for root rot instead of waiting. Here is how to do it in a few simple steps:
How to Fix Root Rot in a ZZ Plant
- Set up a working space by spreading a tarp or newspaper and have clean and disinfected shears handy.
- Use gardening gloves to protect yourself from the irritating plant sap.
- After gently tapping the pot’s sides, tip it over and pull out the plant.
- Clean away the soil from the roots and look for mushy and bad-smelling roots or rhizomes. If you find any, cut them off with clean shears.
- Next up, prepare a potting mix with 70% well-draining cactus soil and 30% perlite.
- Pick a pot with 2-3 drainage holes and fill it halfway with the fresh potting mix.
- Place the plant in it so it is almost at the same level as in the old pot.
- Adjust the soil level accordingly, and fill the pot with the remaining potting mix.
- Tap the soil gently and leave it to dry out thoroughly before watering again.
- Lastly, prune away any mushy or rotten-looking leaves/stems to prevent the above-soil rot from spreading.
Signs of an Underwatered ZZ Plant
In my experience, it is less common for a ZZ plant to die from underwatering. Their exceptional ability to tolerate drought-like conditions helps them survive an occasional dry spell.
But like any other plant, prolonged underwatering can lead to undesirable problems. Here are the key symptoms a constantly dehydrated ZZ plant exhibits.
Dry Leaf Tips
A ZZ plant has succulent-type qualities, which are noticeable in its leaves. Its leaves have a thick, full, and smooth texture thanks to the water they hold inside.
When the plant is underwatered, the leaves lose this water and start to wilt, dry, and brown near the tips. They also lose their tautness and feel softer to the touch. It is the first sign that the plant needs more water.
If your ZZ plant starts dropping leaves one by one, it might be trying to tell you that it’s thirsty. This plant drops leaves when it has limited resources, and doing so allows it to conserve energy that it can use for the plant’s survival.
The petiole is the tender stalk that connects a leaf to the main stem. When a ZZ plant is thirsty, its petioles shrivel and wrinkle. It usually starts from the petioles close to the base of the plant.
Even though this symptom is hard to notice, look for it if other symptoms are present. It will be a definite sign that your beloved ZZ is dehydrated.
Fixing the Problems Caused by Underwatering
The only way to fix an underwatered ZZ plant is to give it a deep soak. Keep watering until it starts flowing out of the drainage holes.
Observe closely and do a chopstick test to see if the soil is absorbing water or if it is just draining down the sides of the pot. It usually happens when the soil has become compacted, or the plant is root-bound. If that is the case, the only way to fix it is to change the soil.
Until then, you can bottom water your plant by placing it in a tray and filling it with water. Empty the tray when the soil has absorbed water thoroughly, or refill it if needed.
In my opinion, the most important principles regarding the ZZ plant’s watering are these:
- Overwatering is the plant’s biggest weakness.
- When in doubt, it is always better to forgo watering until you’re sure.
- Checking the soil is the safest way to determine whether the plant needs water.
And if, unfortunately, your plant has started showing signs of being overwatered, it is better to take it out of the pot and check it for root rot rather than waiting and seeing.
But no matter the situation, this guide will always be here to answer all the watering-related questions for your ZZ plant!
- How long can a ZZ plant go without water?
A ZZ plant can survive without water for up to a month. After which, it’ll start developing symptoms like dry and dropping leaves. The plant will not immediately die, but it will start fighting hard for its survival by this time.
2.Can I spray water on my ZZ plant?
ZZ plants are naturally found in arid environments. They have evolved to use water only when essential, so spraying or misting a ZZ plant is not recommended. To clean the leaves, you can use a clean cloth and wipe them gently.
3.Should I bottom-water my ZZ plant?
It is not recommended, but if the water simply flows down the sides of the pot without absorbing into the soil, you may need to bottom water your plant. It usually happens when the soil compacts or the plant becomes root-bound. In both cases, it is recommended to change the soil and plant in a bigger pot asap. Until then, you can bottom water the plant to keep it alive.
4.How do I tell if my ZZ plant is overwatered?
A ZZ plant is more likely to die from overwatering than underwatering. Here are some key overwatering symptoms to look out for:
- Yellowing leaves
- Many leaves dropping at once
- Wilting stems and leaves
- Soft and mushy spots on the plant
- Root rot
5.How do I tell if my ZZ plant is underwatered?
A ZZ plant can survive dry spells, but it will exhibit consistent dehydration through the following symptoms:
- Dry and browning leaf tips
- Leaves dropping one by one
- Shriveled petioles
6.Can I use tap water to water a ZZ plant?
Even though tap water contains a higher concentration of minerals and salts, it is generally safe for watering a ZZ plant. However, if you can easily give it filtered or distilled water, that’s even better.