Cactus Not Growing (And How To Solve The Most Common Issues)

Cacti are some of the most unusual plants and this is what causes a lot of interest in them. Many plant lovers increasingly prefer cacti as houseplants. But if a cactus grows in conditions that are not native to it, it can be difficult.

Not enough sun, overwatering, and dormancy period are the main reasons why the cactus does not grow. To revive a cactus give it at least 5 hours of direct sunlight, water only if the soil in the pot is completely dry. Also, the room where the cactus grows must be well ventilated with moderate humidity.

Overwatering is the most common cause of not growing cactus

One of the most common mistakes is to think of the cactus as a common indoor plant. Coming out of this, many plant lovers water the cactus on a schedule, such as once a week. But this is a critical mistake, if the roots of the cactus are in constantly moist soil, they will soon rot.

Native cactus conditions involve no rain for weeks or even months. If you do not recreate these conditions at home, you will get a sick cactus that will not grow.

Symptoms:

• The cactus does not grow and shrivels.
• Brown spots can be seen where the plant comes out of the ground.
• The cactus may even lie on the ground.
• The ground in the pot is constantly wet.

Solution:

• Remove the rotten roots and re-root the cactus in sterile succulent soil.
• Treat the wounds with an aqueous solution of hydrogen peroxide at a 1:10 ratio (water:hydrogen peroxide).
• Water the cactus only when the potting soil is 100% dry.
• Be sure to use a pot with large drainage holes.

Not enough sunlight

The sun is the source of the life force of all plants. As for cacti, they are even more demanding to the amount of sunlight. In nature, cacti grow in deserts where there is no shade and only scorching sun all day long.

This is difficult to achieve when growing indoors, so you have to provide at least a few hours of direct sunlight per day. Otherwise, the cactus will stretch out and become thin. Growth will come from the accumulated energy reserves, and when they run out, the cactus will stop growing.

Also, sometimes large amounts of direct sunlight can damage the cactus. This often happens with tropical cacti or if the cactus is placed too close to the south window glass.

Symptoms:

• The cactus becomes elongated, thinning, and bent.
• The cactus slows down at first and then stops growing after a while.
• The plant is growing in a dark room without direct sunlight.

Solution:

• Move the cactus to a sunnier location with at least 4-5 hours of direct sun. Do this gradually, increasing 1 hour of sunlight time per week. Otherwise, the cactus can get burns.
• The ideal location for growing the cactus would be an east or west window.
• If natural light is lacking, use artificial light.
• Be careful when growing a cactus on a southern window as some species may burn and stop growing.

Dormancy period

This may be news to you, but the dormancy period is vital for plants. This is when they are resting and storing their strength for a new growing season. Obviously, they do not grow during this period.

Regarding cacti, they have two hibernation periods per year.

The first period is winter. When there is less sun, cacti slow down their growth so that they do not stretch out and lose their strength. This period can start in October or November and lasts until March. At this time you need to reduce watering but not stop it completely.

The second period is summer dormancy. When the sun is shining and scorching at maximum strength, cacti also slow down their growth so they don’t damage their tissues or lose water. This period can last about 30-40 days in mid-summer.

From all this, it follows that cacti are quite slow plants. You shouldn’t expect them to grow as vigorously as echeveria for example. Be patient and your spiny pet will look good and healthy.

Symptoms:

• The cactus does not grow in midsummer when it is hot.
• The cactus does not grow from late fall to early spring.

Solution:

• During the summer dormancy period, slightly reduce watering and shade the cactus from the scorching sun.
• During the winter dormancy, water the cactus for 2 weeks after the potting soil is completely dry.

Poor air circulation

Like all plants cacti like clean and fresh air. They absolutely do not tolerate stagnant air and high humidity because it can provoke the development of fungal disease. The structure of the cactus is quite watery and this is a perfect environment for rot.

In addition, if the weather is very hot and the cactus is close to a windowpane with poor air exchange, it can droop.

The need for fresh air does not mean that the cactus will tolerate draughts. In fact, this is another problem, if it grows in a place with drafts of cold then it can get damaged and stop growing.

Symptoms:

• The cactus is not growing and you can see brown spots on it.
• The place where the cactus is growing has poor ventilation and/or high humidity.
• The cactus is drooping.

Solution:

• Make sure the room is well ventilated.
• Do not place the cactus in the bathroom.
• Do not place the cactus near an air conditioner, refrigerator, etc.
• Do not place the cactus where there may be cold drafts.

Pot and soil issues

The first problem here is that the pot is too big. The fact is that if a cactus grows in a very large pot, the soil may not dry out for a long time and the roots can start to rot. To avoid this, the size of the pot and the amount of potting soil should be such that no rootbound occurs, but no more.

The second problem is soil with a high organic matter content. In this case, there will be an overabundance of organic fertilizers and water will be held in the soil for a long time.

These two problems will certainly cause the cactus to stop growing sooner or later and become diseased.

Symptoms:

• The cactus does not grow and turns yellow or brown.
• Cactus roots are rotten.
• The size of the pot is 2-3 times the size of the plant itself.
• The soil is too moist.

Solution:

• Remove the rotten roots and treat the wounds with hydrogen peroxide.
• Transplant the cactus into clean cactus potting soil with a minimum of organic matter and plenty of drainage material (perlite, etc.).
• The pot should not be much bigger than the cactus and should have at least 4-6 large drainage holes.

Not enough nutrients

Very often the cactus does not grow through a lack of nutrients in the soil. And this is quite normal because in desert areas where cacti grow there are very few nutrients. This is the reason why cacti do not like soil rich in organic matter.

Cacti prefer to grow in stony-sandy soil and this implies a slow growth rate. Room conditions slow it down even more, so you get the impression that the cactus is not growing, when in fact it is just growing very slowly.

To give your cactus some energy you can fertilize it. But do it without organic fertilizer and only during the growing period.

Symptoms:

• The cactus is not growing or is growing very slowly.
• No daughter plants appear.
• The needles of the cactus are very thin and their number is minimal.
• The cactus does not flower.

Solution:

• Fertilize the cactus once a year at the beginning of the season.
• Use a slow-release fertilizer designed for cacti or succulents.
• Avoid using compost and other organic matter as fertilizer.
• Avoid fertilizing during dormancy.

Transplant shock

All plants are constantly growing and developing and sooner or later they will need more space. This also applies to cacti, if you don’t transplant them for a long time, the roots may not have enough space. As a result, the plant will stop growing until you repot it.

That would be all right, but very often after transplanting, plants get stressed. This is called transplant shock. Cacti also sometimes experience transplant shock after transplanting, and one of the symptoms is that they stop growing for a long time.

You might get the impression that no matter what you do, the result will be that the growth stops. But no, if the cactus needs to be transplanted, then transplant it. Do it very carefully, so that you do not damage any of the roots, and reduce the amount of direct sunlight time, and after a while, your cactus will be back to normal.

Symptoms:

• The cactus does not grow after transplanting.
• The roots were damaged during transplanting.
• The cactus is shriveling and fading.

Solution:

• Do not damage the roots or the plant itself during transplanting.
• Use only good-quality succulent mix.
• Reduce the amount of direct sun to 1-2 hours per day. Water the cactus a little less frequently. When you see the cactus begin to grow, gradually return everything to normal.