Although easy to grow, rubber plants can be nit-picky about their watering requirements. They’ll likely shed leaves if you keep the soil mix either too wet or too dry. If you’ve decided to add a Ficus elastica to your houseplant collection, it’s crucial to ensure you’re irrigating it properly.
Rubber plants prefer soil to remain steadily moist but NEVER wet. For a consistent watering schedule, check the soil often using a moisture meter or your finger. When the top 1-2 inches of the soil is dry, it’s time to irrigate your rubber plant.
Of course, that’s easier said than done. That’s why I put together this practical guide to help you get a good feel for how much and how frequently to water your rubber plant correctly.
I’ve also included handy watering tips and telling signs your plant needs a drink. Also, look ahead for how to recognize the dreaded symptoms of an overwatered rubber plant.
Contents
Factors That Impact Rubber Plant Watering Frequency
[1] Seasons
As with most native tropics, Ficus elastica needs more water during the growth period (from early spring through summer) than when it’s not actively growing, usually during winter and fall.
In Summer and Spring:
When the chill disappears and the weather starts to warm up, spring cleaning isn’t the only thing that sets things abuzz. Your rubber plants also love the warmth.
Heat encourages them to spring back to life and start growing, with the analogous need for resources required for optimal growth.
You will notice that the soil mix dries out faster than before during summer and spring, and with good reason. Firstly, your rubber plant uses up more water during this growth spurt.
It’s not only required for photosynthesis but also helps ship nutrients wherever they’re needed.
Secondly, the higher temperatures cause moisture to evaporate more quickly from the potting soil.
Thirdly, rubber plants lose more moisture during hot weather from the leaves through increased levels of transpiration, evaporation, and respiration.
So, it’s crucial to monitor soil moisture more closely during this period. Check the soil moisture every four to five days or sooner.
Water again as soon as the top one to two inches are dry or crumbly. If the topsoil is still fairly moist, check back after a day or two.
In Fall and Winter
The opposite is true come fall and winter, which is when your rubber plant starts to slow things down.
It doesn’t love cold, and it’ll respond accordingly by reducing growth, sometimes to a point of dormancy deep into the chilly winter season.
The soil will also stay moist for longer. That’s because your plant gets less amount of natural sunlight during this period, resulting in less photosynthesis. In turn, less water is required for transpiration and respiration.
The worst thing you can do is give your rubber plant too much water when, in fact, it doesn’t need much of it. The excess soil dampness promotes root rot and other diseases.
During Flowering
While Ficus elastica plants can flower, they seldom blossom as houseplants. Instead, they put out eye-catching bright red to burgundy spathes that eventually open to reveal new leaves.
These sheaths will get detached and fall off once the new foliage unfurls.
The sprouting of new spathes often coincides with when rubber plants would start flowering in their native tropic forests.
Put otherwise, this typically occurs in spring and continues throughout summer, call for more watering to compensate for increased activity.
[2] Size of The Plant
Rubber plants are fairly fast growers and you’ll have to repot it once every year until it reaches mature growth of 6-10 ft. indoors.
Each large, glossy oblong leaf your plant produces is a beehive of activity. The chlorophyll (green pigment) uses light to turn water and carbon dioxide into nutrients and energy.
It’s quite a sight to see how your rubber tree plant turns any spot in your room into lush greenery.
That means the larger your plant gets, the more water it’ll need to churn out nutrients, respire, and grow more robustly.
(Source: Clemson University).
[3] Temperature
Like most tropical plants, your rubber plants like the warmer side of things. Nearly all cultivars of this jungle evergreen thrive when temperatures are in the range of 60-80ºF (15-26°C).
They prefer the higher end of the temperature range during the day for optimum growth.
As noted earlier, warmer temperatures not only cause the potting soil to dry out fast but also encourages growth. So be sure to increase watering as needed when temperatures are on the toasty side.
During winter when temperatures start to drop, you must reduce water frequency accordingly.
However, make sure that temps don’t suddenly dip below 55° F (13°C), especially when it’s drafty. This may cause your ficus elastica to drop leaves.
If it does shed leaves, stop watering until you see signs of new growth. But wait until the top 1-2” of soil has dried out a bit to avoid inviting rot diseases.
[4] Humidity
Because of their tropical nature, rubber plants do best in humid environments. They tend to lose more moisture to transpiration. You can think of it as the way you and I lose moisture through sweating and breathing.
If the air around your ficus plant is dry and drafty (usually during winter), it’ll get thirsty sooner rather than later. As such, you must check the soil moisture and water more frequently.
[5] Location of The Plant
Sitting in a brightly lit or hotter spot can make you mighty thirsty, and the same is true of your rubber plant. It prefers to be parked in an area that receives bright, indirect light.
If it’s located in a window with blazing or sunny southern or western exposure, you will have to water it more often. Likewise, you must give your plant more water if it’s in a dry, drafty area, perhaps in the path of hot drafts or near a fireplace.
[6] Type of Pot
I’m a big fan of garden pots made from porous materials like terracotta, unglazed ceramic, or clay. They encourage fast-drying of soil through permeable walls and creates a humid microclimate for my rubber plants.
Nonetheless, that doesn’t counter the fact that the soil dries out fast, so you’ll need to double down on the watering frequency, as well.
If your rubber plant is potted in a glass, glazed ceramic, or plastic container, the soil will likely remain moist for longer.
That’s because these materials are inferior when it comes to permeability. For this reason, you must ease up on watering, lest the soil becomes soggy and root rot sets in.
All rubber plant pots must have drain holes in the bottom, regardless of the material. This will help drain perched water, as rubber plants don’t like standing in stagnant water or so-called “wet feet”.
The more the drainage holes, the sooner the soil will dry out. That also translates to a higher watering frequency.
[7] Size of the Pot
The pot acts as a reservoir for your Ficus elastica. If the pot is too small for your plant, the soil’s capacity for holding water is limited. That way, the soil dries out very quickly, needing regular watering.
The container should match the size of your rubber plant to ensure even soil moisture. Ideally, there should be about an inch of potting soil around your rubber plant.
A container that’s too large for your plant will retain moisture for longer. In a worst-case scenario, localized soggy areas may develop in areas where the roots don’t reach. Usually, around the edges and in the bottom.
[8] Type of Potting Mix
You know how important the right potting soil is for your plant. Your rubber plant is actually tolerant of most soil types. In fact, any fast-draining potting mix will do just fine, be it clay, sand, or loam.
The overarching requirement is that a Ficus elastica doesn’t like its feet wet. But the drainage and water retention capacity of the potting mix will define how often you should water it.
If the soil is organic-rich and retains water for longer, you should be careful not to overwater your plant. This puts it at risk of diseases, such as crown, stem, and root rot.
If the soil is free-draining with high content of sand, vermiculite, perlite, etc., you’ll want to increase irrigation frequency to avoid the potting mix from drying out completely.
How Do You Know If a Rubber Plant Needs Watering?
Now that you’re familiar with factors that affect the watering frequency, you must also know how to spot an underwatered rubber plant.
[1] Test Moisture Level using your Finger or Stick
The easiest and most reliable method to know if your plant is thirsty is to check the soil moisture every 4-5 days after watering. You don’t have to invest in an expensive apparatus when you can use a stick or your finger.
- Stick your finger/stick approximately two or so inches into the topsoil
- If it’s still moist, check back after every one or two days
- Allow top one to two inches to dry out before you water again
When your rubber plant isn’t actively growing during autumn and winter, the potting mix may take longer than a week to dry out. Be patient. The last thing you want is to kill your precious Ficus with too much of a good thing!
[2] Potting Soil Color
This one is a no-brainer — moist soil usually takes a darker hue. Dry soil, on the other hand, is typically grayish and lighter in color.
If the soil is too damp, this will support the growth of mold, mildew, and other fungi. This will appear as a moldy cover on the surface of the soil. This may also be a dreadful sign of root rot due to overwatering or waterlogged potting mix.
[3] Wilting or Drooping Leaves
Rubber plants boast spritely oversized lush, perky leaves with strong veins. They slant upwards in a graceful gait. When you notice that they are wilting and drooping, that’s one of the earliest signs your Ficus elastica is thirsty.
Wilting oftentimes begins with lower/older leaves. This is a natural survival tactic whereby your plant favors new foliage over older ones when resources are scarce.
[4] Brown Leaf Tips
Do the tips of your rubber plant’s leaves appear burnt or crisped up? Dried out and browned leaf tips and edges are a telltale sign that your plant is very thirsty.
[5] Leaves Wrinkled
When heavily dehydrated, leaves lose a lot of water and contract, forming wrinkles on the leaf surfaces. In fact, when the exposed outer layer of the leaves starts to pucker, that’s a clear indication that you need to water your rubber plant.
[6] Leaves Turning Brown or Yellow
If the dehydration spell is longer than usual, you’ll probably find dying or dead foliage. Perhaps you went on vacation and your friend or house-sitter left the soil to dry out completely.
Browned or yellow leaves instead of lush, glossy green foliage with a burgundy tinge is another sign of an underwatered rubber plant.
[7] Leaves Drying Out and Falling off
One of the first signs to appear due to underwatering is dry, crispy leaves. They do so due to loss of turgor pressure because your plant isn’t getting enough water from the soil. Eventually, the leaves will dry up, wilt, and fall off.
You must first rule out other possible culprits of leaves falling off. Rubber plants may naturally shed older leaves. But cold drafts, low light, lack of humidity, and sudden changes can result in the same.
[8] Measure the Weight of The Pot
Not the most reliable way, but a lighter pot may indicate that your rubber plant wants a drink. Carefully lift or weigh your plant right after watering to get a sense of its weight when well-watered.
[9] Use Moisture Meter
This is definitely the most effective way to ensure a consistent watering routine for your rubber plant. To get more value for your money, I suggest that you invest in a quality multi-function meter that can read soil moisture, as well as humidity, temperature, and other growth parameters.
[10] Use an App
It’s important to check on your rubber plants once a week or more to see if they need watering. But it’s easy to forget, so using an app like Happy Plant, Waterbug, etc., can be a useful reminder.
Signs of Overwatered Rubber Plant
Here’s the truth: it’s easier to kill your rubber tree from overwatering than underwatering. That’s why you should be able to spot an overwatered Ficus elastica sooner rather than later.
Look out for the following dreaded symptoms of overwatering:
- Brown or yellow, limp leaves
- Wilting and drooping leaves, both new and old ones
- Brown spots on leaves with yellow halos
- Leaves Cracking
- Moldy growth on top of potting mix/soil
- A rotten smell emanating from soil
Don’t ignore the indiscriminate wilting of leaves, as this is often an early sign of root rot.
How to Water Rubber Plant
[1] Watering from Above
As a tropical plant species, rubber plants often prefer watering from the top. They appreciate the extra humidity that comes from top irrigation. Here are a few things to keep in mind:
- Use rainwater, filtered, or distilled water, preferably room temperature water
- Water at the base, making sure to avoid splashing on the leaves
- Water until liquid passed through the drain holes in the bottom
- Dump out perched water from the saucer after 10 minutes
- Let the top 1-2inch of the soil dry out before the next irrigation
[2] Watering from Below
If your plant’s pot has drainage holes, this is an excellent watering method.
- To water from below, you must first fill a shallow dish, basin, or tray with room temperature water up to 1” (2.5 cm).
- Put the pot inside the basin without the saucer, allowing your rubber plant to soak up water for around fifteen minutes.
- Remove the pot from the basin once the potting mix is evenly moist. Drain the excess water as much as you can by tilting the pot.
- Move your rubber plant to its default spot, let the excess collect on the saucer then dump it out.
- Don’t forget to water your ficus from above from time to time to get rid of salts that may accumulate in the soil.
[3] Self-Watering Pots
Self-watering pots remove the guesswork out of irrigating your rubber plant.
- All that you have to do is refill the water reservoir with filtered or distilled water at least once every month or when needed. Then set it and forget it!
- Some of the higher-end models come with a built-in water filtration system.
- A model with a see-through reservoir or water meter will make for a more hassle-free operation.
Golden Rules of Watering Rubber Plants
- Keep the soil uniformly moist — to do so, use the correct size pot and water until water escapes from the drainage holes.
- Allow the top 1-2 inches of soil to dry out between waterings
- Water early in the morning — this is especially important if you water from above. This will give any water splashed on the leaves enough time to evaporate during the warmer hours of the day.
- Water away from the leaves — Leave dampness invites some diseases and pests. Instead, water at the base where roots are.
- Ensure water reaches the roots — Irrigate until water comes out of the drainage holes
- Avoid water logging — Only water when topsoil has slightly dried out. Repot if the soil becomes waterlogged.
- Use fast-draining potting soil, such as a cactus mix
Watering Rubber Plants After Repotting
Rubber plants are heavy growers, particularly when the growing conditions are perfect. In most cases, you should repot once every year until it achieves the max height of 6-10 feet.
- Use a well-draining potting mix like cactus or orchid mix that includes sphagnum, perlite, or vermiculite
- Water before repotting. Water until excess water escapes from the drainage holes. This is a great way to ensure the soil is uniformly moist.
- Don’t forget to allow the pot to drain thoroughly. This way, the potting mix won’t be messy or muddy when you’re repotting.
- After repotting, give it bright, indirect slight and don’t disturb until you see signs of new growth
- Water again when the soil has dried out a bit following techniques outlined above
Final Words
- Rubber plants call for a consistent watering schedule — make sure the soil is moist but not soggy
- Water again only when 1-2 inches of topsoil has dried out.
- Water early in the morning at the base of the plant