Why is My Cactus Turning Brown and Soft

The Cactaceae, commonly known as the cactus, is an excellent houseplant, one that is popular all over the world, including the USA.

With unique adaptive features that make it exceptionally tolerant and resistant, the cactus is perhaps the best house plant for a new plant enthusiast.

However, despite the many unique qualities that give a cactus its incomparable endurance, prolonged periods of poor care and neglect will eventually cause the plant to die well before it should.

If your indoor potted or outdoor planted cactus is turning brown and soft and is losing its ability to remain upright, you need to change your plant care routine.

Keep reading to learn about why your cactus is turning brown and soft.

What Makes a Cactus So Tolerant?

For a species to survive long-term, it needs to evolve and adapt to its living conditions.

Since the cactus is a desert plant that commonly grows in extremely hot and dry environments where water is scarce, it has successfully adapted to thriving in such harsh conditions.

In general, all species of the Cactaceae family have thorns and spikes instead of leaves. Since a plant’s leaf is the primary organ that connects it to its surroundings, it is responsible for all kinds of water loss.

By evolving into its thorny, leafless self, the cactus has managed to minimize its water loss, allowing it to thrive in drought-like conditions for surprisingly long periods.

Moreover, unlike other plants with long, thin stems, the cactus is known for its thick fleshy trunk. Just like a camel uses its hump to conserve water reserves for long periods, cacti use their thick trunks to do the same.

As a result, even when there is not enough rain or no external watering for months, the cactus can live off of its stored water reserve to stay healthy and maintain its shockingly long lifespan.

What is Causing My Cactus to Turn Brown and Soft?

Although the cactus is a prime example of a plant that has undergone one of the most remarkable natural adaptations, it still has its limitations and can die if not taken care of.

While a cactus plant will endure poor care for a while, the signs of declining health and early death will eventually become evident. Two of these signs include the cactus turning brown and soft.

If your cactus is losing color and its characterized firmness, pay attention to the possible reasons listed below.

Frequent Overwatering

To thrive in the hot and dry desert conditions, cacti have adapted to forming thorns instead of leaves and water-storing trunks instead of stems.

Moreover, since a cactus’ roots tend to dig deep into the Earth to find any traces of moisture, they have developed the unique ability to absorb any amount of water they find.

Hence, it is safe to say that plants like the spikey cactus will thrive in deprivation as they do not require much water to survive.

However, when plant parents frequently overwater their potted or planted cactus, they are actually killing it. This is especially true in the USA, where people tend to keep more than one plant species in their homes.

Since the cactus roots are adapted to absorbing any amount of water provided, they will soak up all the excess water that has accumulated inside their pot.

When this water travels up the plant, it is pushed out of the water-carrying vessels. Eventually, the entire water-drenched cactus plant becomes extremely heavy, mushy, and soft, which causes it to lose its ability to remain upright.

Moreover, due to the excess water present in the plant’s flesh, the plant is more likely to fall victim to a fungal infection. This causes the cactus stem or trunk to rot, which results in the plant losing its natural green color – and then it turns brown.

This condition or disease is usually called tip rot, cactus stem rot or root rot, and it is enough to kill a healthy and tall cacti plant within a month.

Insufficient Direct Sunlight

Apart from being used to dry desert soil, cactus plants are also well-adapted to grow in brightly-lit environments. Although long hours of direct sunlight will burn the cactus plant’s outer body, dim and dark conditions have their own detrimental impacts.

Since cacti need the energy from the sun’s light to carry out photosynthesis and produce plant food, it will suffer from food and energy deprivation when left in dimly lit and heavily shaded environments.

As the production of sucrose slows down, the plant is no longer able to synthesize chlorophyll, the chemical compound that gives a plant its green pigment. As a result, the plant will eventually develop brown and yellow spots all over its body.

Too Much Direct Sunlight

Although sunlight is crucial for a growing or tall cactus plant, too much direct sunlight can also be dangerous.

If a potted cactus is left on a sun-facing window sill or is grown outdoors without any shade, the sun’s intense heat and light will cause its body to burn. This will cause the cactus’ body to turn brown, yellow, and at times, black.

High Atmospheric Humidity

If you water your cactus plant infrequently, but you’re still struggling with the cactus turning brown and soft, you should check the atmospheric humidity levels.

If the air has too much moisture, it will cause the cactus’ soil to remain mildly wet at all times. When you add water to the wet soil, you unknowingly overwater your desert plant.

As a result, when the cactus absorbs all the water available to its roots, the water pressure leads to its trunk turning mushy and soft, along with causing it to rot from the inside out.

Eventually, the cactus turns brown and yellow and then dies.

Poor Quality Pot

While most experienced plant caretakers understand the importance of watering a plant as per its needs, not many know about the lasting impacts of a poor-quality pot.

Ideally, drought-tolerant plants like the cactus should be grown in highly-absorbent terracotta pots designed to soak up all excess water from the soil it carries.

Moreover, the pot should also have sufficient and unclogged drainage holes to help drain out any excess water if you accidentally overwater your cactus plant.

However, if the cactus is grown inside a metallic or plastic pot that is completely non-porous and lacks sufficient drainage holes, the potting soil will not dry up on its own.

As a result, the potted cactus will absorb all the water, which will cause its trunk to turn brown and soft.

Poor Indoor Ventilation

If you water your indoor potted cactus once every two weeks, and the atmospheric humidity levels are within the right range, then your cactus might be turning brown and soft due to poor indoor ventilation.

Without a proper exhaust fan or ventilation system, any moisture in the air will start accumulating inside the house. This will cause the cactus’ soil to remain wet at all times, resulting in stem rot and the loss of firmness and color.

Altman Plants, Assorted Cactus Plants Live Plants (4 Pack), Live Cactus Plant Live Succulents Plants Live Houseplants, Cacti Live Indoor Plants Succulent Plants House Plants in Cactus Soil Potting Mix

Final Thoughts – Take Care of Your Cactus Plant Before It Turns Brown and Soft

The desert cactus is an excellent house plant for people in the USA looking for easy-to-manage plant species. Not only is this plant exceptionally tolerant, but it can also endure prolonged periods of poor care and neglect.

However, if you make a habit of overwatering your cactus for many months or you deprive the desert plant of proper light, its stem will turn brown and soft. To keep your cactus healthy, green, firm, and tall, water it on a proper schedule, provide it with sufficient indirect sunlight, and plant it inside a highly-porous terracotta pot.