How Often To Water ZZ Plant

If you know anything about ZZ plants, you will have heard that overwatering them is not a good idea. They abhor wet feet and can sicken and die if the potting mix is constantly wet. But how do you know how often you should water your plant?

How often you should water your ZZ plant depends on several variables, including temperature, humidity, light intensity, air circulation, pot size, and climate. Watering requirements also change with the seasons. Your plant needs watering only when the top few inches of soil are dry to the touch.

You, therefore, need to appreciate the environmental conditions in which you keep your ZZ plant in relation to your local climate, whether you use air conditioning or central heating, how bright the light is, and how much humidity and ventilation there is.

Local Climate

Why do you need to know your local climate? Because this gives an idea of how dry your air is likely to be, the average evaporation rates.

Air humidity, temperature, and air circulation also change from season to season, so if you have very dry, mild winters, you may have to water more frequently than in cold winters with lots of precipitation.

Evaporation of water from the soil in the plant pot will be slower if the humidity in the air is high. This translates to less frequent watering. Higher air temperature also contributes to increased evaporation, so cooler air generally means less watering.

Dry Climate

Plant in a dry soil climate

In dry climates, moisture rapidly evaporates from the air, and precipitation is low. Deserts and steppes are examples of dry climates. They experience significant seasonal and daily temperature fluctuations. For instance, the day can be blisteringly hot in a desert while the night is freezing.

Dry climates include arid and semi-arid regions in the western United States, Australia, southern and central Africa, southern South America, and large parts of Asia.

In a dry climate, your ZZ plant will need water more frequently because the water evaporates faster into the surrounding atmosphere. You may also have to mist your plant regularly to improve humidity or even buy a cool-mist humidifier to prevent the potting mix from drying out too rapidly.

The ZZ plant likes an average indoor humidity of around forty percent. Although it is drought resistant because it stores water in its rhizomes, the leaves will start to fall off if it is dry for too long. Another thing you could do to address the dryness in the air is to put the pot on top of stones or gravel in a flat tray filled with water.

You may need to water every third or fourth day in a very dry climate, but you should always feel with your finger for moisture in the substrate before watering. It should be dry before you water. If the air around your ZZ plant is humid because you mist regularly or use a humidifier, you may only need to water it once a week.

Read more: Zamicro Zz Plant

Tropical Climate

A tropical climate is hot and humid, with average temperatures above eighteen degrees Celsius, or sixty-four degrees Fahrenheit all year round. These areas have high rainfall – above fifty-nine inches of precipitation every year.

Tropical climates can also have widely fluctuating temperatures during the day and are usually dry in summer and wet in winter. The daily temperature difference can be as much as twenty degrees Celsius in mountainous areas.

Many indoor plants originate from tropical climates, and the ZZ plant is considered a tropical plant. This does not mean you have to live in a tropical environment to keep one. It helps to understand that the plant is adapted to withstand dry periods followed by torrential rain.

The ZZ plant can store water to get it through dry periods, so this means you don’t have to water it as frequently as many other indoor plants. Also, when you water it, drench the potting mix until you see liquid running out of the pot’s drainage holes. It is vital that the substrate drains well and doesn’t retain much water.

If you forget to water it on occasion, the plant is very forgiving. However, if you leave it dry for too long, it will drop its leaves to prevent water loss.

In a tropical climate, the air will probably have the forty percent or higher humidity level required by the ZZ plant, and you don’t have to invest in a humidifier or mist the leaves too frequently. It is likely to need water once a week in summer, but only once every two to three weeks in winter.

Always test to see if the soil is dry before you water. You can insert an untreated wooden chopstick in the potting mix right down to the bottom of the pot. If it comes out clean, water your plant, but if it comes out with soil attached, it is still moist, and you shouldn’t water.

zz plant leaves

Temperate Climate

In temperate climates, summers are typically warm, humid, and punctuated by thunderstorms. Rainfall is moderate throughout the year, with sporadic dry periods. Average monthly temperatures are above ten degrees Celsius in the warmer months and above minus three in the winter.

The majority of the world’s population lives in coastal and inland temperate zones.

In a temperate climate, the higher humidity in the summer may mean you need to water your ZZ plant less frequently because evaporation slows right down. If the air is dry, you may have to water more often in winter.

However, you also have to take account of the ambient temperature because the ZZ plant does not usually grow in winter and so needs less water.

The general rule is that if temperatures are low, your plant needs less water than when they are high. If you use air conditioning or indoor heating, evaporation rates will rise. You may need to water your ZZ plant more often in this case.

As a rough guide, you should water your ZZ plant weekly in the summer and fortnightly in the winter but always test the soil for moisture before you water.

Also Check: Zz Plant Rhizome

Continental Climate

Continental regions have bitterly cold winters and hot summers and are subject to temperature extremes. The air is relatively dry, and they get mainly summer rainfall. Most continental climates occur in the northern hemisphere because this is where the majority of the Earth’s landmass is found.

Examples in the United States include Alaska, California, Arizona, and Oregon. Cities like New York, Indianapolis, Chicago, Detroit, Denver, and Salt Lake City have continental climates.

A ZZ plant is not frost and cold tolerant, so you will have to keep it indoors. It will grow more slowly in cooler, low-light conditions than in warmer bright ones.

Slower growth means less frequent watering. Since air conditioners and heaters dry out the air, the humidity is likely to be low, which means more frequent watering. You have to strike a balance between temperature and humidity. You need to water more frequently in the hot summer months – once a week or so.

If you use indoor heating in the winter, the room temperature may be very comfortable but dry, in which case watering once a week may be required. However, the ZZ plant usually goes dormant in winter, so watering may only be needed every two to three weeks.

Air Circulation

Air circulation around your ZZ plant will affect the amount of moisture it retains. Most indoor plants require some ventilation and the ZZ plant is no exception. This doesn’t mean you should train a fan on it in still conditions!

However, if the air in your home doesn’t circulate well and tends to be still, evaporation of moisture from the potting soil and leaves of the plant will be much slower. This is also the case if you cluster many plants together to improve the humidity. 

Poor air circulation and high humidity mean you won’t need to water your ZZ plant as often as in good circulation with low humidity.

Pot Size

Different size pots for sale

If your plant is in an overly large pot with plenty of substrate, there is a risk of overwatering because it dries out more slowly. The ZZ plant likes to be slightly rootbound, so the pot should only be a couple of inches wider than the rootball. If you have put it in a large pot, it may need water less often.

Since it must be left to dry out between waterings, the best way to know when to water is to see if the top few inches of soil are dry.

Light

In bright light, your ZZ plant will grow faster than in low light. Faster growth equates to more frequent watering.

Conclusion

Climate, temperature, humidity, pot size, humidity, ventilation, and season all affect how frequently you water a ZZ plant. Because they vary significantly, one can’t say with certainty how often you need to water. It is best to check that the top few inches of soil are dry before watering.

References:

https://scijinks.gov/climate-zones/

https://www.britannica.com/science/climate-meteorology

https://sciencing.com/characteristics-dry-climate-4878.html

https://www.sciencedirect.com/topics/earth-and-planetary-sciences/tropical-climate

https://www.sciencedirect.com/topics/earth-and-planetary-sciences/temperate-climate

https://www.worldatlas.com/articles/what-is-the-continental-climate.html