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6 Causes of Rubber Plant Leaves Cracking (And Solutions)

It is common to grow rubber plant leaves because of their lush green color. It will be heartbreaking to see the rubber plant leaves crack. The good news is that it isn’t impossible to avoid. Let’s take a closer look at the issue and its possible solutions.

Overwatering and overfeeding can cause rubber plant leaves to swell and break, causing the leaves to appear swollen and the leaf skin break. In addition, the internal tissues of leaves grow faster than the skin, which causes the leaves to crack when they are overwatered and overfed.

Micronutrient deficiency, low humidity, and fluctuating temperatures can also crack the plant’s cell membrane.

The Leaf Becomes Brittle Due to Low Humidity

The Leaf Becomes Brittle Due to Low Humidity
The Leaf Becomes Brittle Due to Low Humidity

The leaves of the rubber tree plant require a high level of humidity. A lack of moisture in the atmosphere will make them more brittle and susceptible to mechanical damage.

A daily humidity level of 50% or higher is required for rubber plants to thrive. The leaves become brittle if there is not enough moisture in the air. Splits can result from even the slightest movement.

Like many indoor plants, Rubber plants are native to rain forests and jungles where the air is constantly moist. They’ve gotten used to the humid air and use it to their advantage to keep their leaves healthy.

Humid air reduces moisture loss from the leaves during transpiration, the process by which the rubber tree inhales and exhales oxygen and carbon dioxide as it converts light to sugar.

This means that less water evaporates from the air when there is a lot of moisture, so less water comes out with the gases. As a result, the leaves can retain their moistness and remain well-hydrated.

Rubber tree leaves are also protected from minor mechanical damage in increasing the humidity. However, the function of leaf secretions that cover the rubber plant’s leaves depends on high humidity. Newer, more vulnerable leaves are particularly susceptible to this.

New leaves emerge with a protective sheath from pests, disease, and mechanical damage. It helps the new leaf slide out of the sheath smoothly when it grows. In addition, they make secretions that act as lubricants so the leaf doesn’t get stuck.

Without that critical humidity, the rubber plant’s leaf secretions dry out and cannot help the new leaf slide free.

Misting Your Rubber Plant

It is the quickest and easiest way to raise the humidity in your rubber plant’s environment to the ideal level. You can increase the local humidity around the rubber plant by directly adding water to the air.

Set the tone for the day with a daily misting, especially in the morning. It’s also an excellent time to clean dust from the leaves and otherwise inspect your plant.

Lightly mist the leaves with cool, clean water in a spray bottle. To avoid leaving marks on the leaves, use filtered water.

Spray evenly, paying particular attention to newly sprouted leaf sheaths. It will help the new leaves unfurl quickly.

You may want to consider a more permanent solution if you keep seeing split leaves. Pebble tray can provide a sustainable solution to maintain the humidity.

The shorter and bushier the rubber plant, the better it will do in a pebble tray. Adding clean water to a shallow tray filled with smooth stones is all that’s required; the stones only need to be partially submerged. Water evaporates from this tray, which provides a steady supply of humidity to plants nearby.

Having my plants on the pebbles, saucer and all, allows the water to seep up into the leaves, allowing them to thrive. Learn more about pebble trays by clicking the link.

If you have a lot of tropical plants, a humidifier may be the most straightforward solution. You can’t go wrong with these humidifiers if you need constant humidity in a large area.

They’re also a great way to jazz up your home’s interior design. (Check the price on Amazon here)

Over-watering Rubber Plant Leaves to Swell and Break

A great paradox of indoor gardening is that over-watering can lead to dehydration in plants.

Root systems require small amounts of oxygen to function. Therefore, small air pockets in the soil are essential for rubber plant roots to work correctly.

The roots begin to drown when the soil becomes soaked due to over-watering. The soil no longer contains the necessary air for them to function. Even if there is a lot of water nearby, they can no longer get it from the soil.

The leaves will soon dry out as the roots are no longer working. They become brittle and dry as a result of this. To learn more about proper watering for rubber plants, check out this post.

Keep your rubber plant moist but never completely submerged if you want your rubber plant to thrive. Only water when the top two inches of the growing medium are completely dry, if at all possible.

Physical Harm to a Tall Rubber Plant

They aren’t very flexible, and bumps and scrapes can easily damage them. This is especially true for plants too big for their pots and isn’t well-balanced.

As with a piece of paper that is frequently folded, a large rubber plant that is commonly knocked or bumped will develop weak spots on its leaves. That crease will become brittle and crack as the leaf ages.

Keep out Larger rubber plants of high-traffic areas like hallways and passageways. If people don’t bump into the plant, they’re less likely to damage its leaves or, worse, knock it over with the pot still on it!

Be on the lookout for pets and children in the area where your rubber tree is located, as well. Curiosity and mischief are two of the most common causes of leaf damage.

Make sure your rubber plant is well balanced and in a heavy enough pot to keep it stable. Ideally, you’ll want to use ceramic or stone/concrete pots. They will be less likely to topple over because of the additional weight.

In my opinion, one or two large decorative stones or statues placed at the base of larger plants also work well. To find a good balance, you may have to experiment with a few different setups.

Avoid covering the entire surface area of the growing medium with a weight if you choose this option. Leaving space for the medium to dry out is critical in preventing mold growth in your mix.

Micro-nutrient Deficiency

Plants need nitrogen, phosphorus, and potassium to thrive, and most fertilizers focus on providing these three nutrients. But that isn’t all your rubber plant needs, of course.

Iron, magnesium, and boron are all necessary to grow sturdy leaves. For the most part, rubber trees have adapted to rely on soil nutrients for their nutritional needs.

However, because indoor plants have limited resources, it is critical to ensure that they are well supported as they grow.

Young plants require frequent applications of high-quality organic fertilizer during the growing season. However, even mature plants benefit from a little extra assistance.

Fertilizer made from natural ingredients contains micronutrients that chemical fertilizers lack.

In addition to worm castings, fish emulsions, and well-aged compost, rubber plants can benefit from various micro-nutrients that are often overlooked.

But if you can’t find them, you can use a custom-blended fertilizer instead. Rubber plants are a type of fig, so use a fig-specific variety. (Check out the prices on Amazon here)

Extreme Environmental Changes

Like all kinds of figs, Rubber plants are notoriously picky about their surroundings’ temperature. Split leaves signify a plant whose temperature fluctuates from one extreme to the next throughout the day.

Temperatures between 75°F (24 °C) and 80°F (27 °C) during the day and no lower than 60°F (16 °C) at night are ideal.

You should try to keep that temperature at the same level as possible if you can. It’s not acceptable for the temperature to fluctuate drastically at all.

If your rubber plant gets too hot, it will often drop all of its leaves as a show of protest.

Keep your rubber tree at ease by providing it with steady, even warmth. At night, a room with a lot of natural light can become surprisingly chilly.

Should You Cut off Damaged Rubber Plant Leaves?

It is up to you whether or not to remove or leave the cracked leaves on your rubber tree after identifying and correcting what’s making them split in the first place.

Suppose the damage isn’t too bad and is primarily cosmetic. In that case, I tend to leave the damaged foliage where it is, even if it isn’t charming. If the leaf is mainly green, photosynthesis can still take place.

However, removing any unsightly leaves by pruning them away is not a bad idea. A little pruning is suitable for rubber plants, so removing a few damaged leaves from time to time is fine. It won’t take long for the rubber plant to sprout new growth points.

However, for rubber plants with extensive damage, try to leave at least two-thirds of the leaves intact and focus on removing only the most severe damage.

Rubber plants produce a milky sap that can irritate the skin, so you should take precautions. Wear gloves while you do this.

Your trimmed plant will be back to its lush, tropical self in no time if you follow proper care instructions.