Cacti are known for their resilience and ability to thrive in harsh environments. However, even these hardy plants can fall victim to root rot, a common and potentially fatal condition. In this blog post, we will explore what causes cactus root rot, what happens to cacti if they have it, and how to treat a cactus with this condition.
What causes cactus root rot?
Cactus root rot is primarily caused by overwatering, which leads to excessive moisture in the soil. It can also be caused by a poor soil composition for the cactus where there is not enough inorganic (pumice, lava rock or perlite, etc) material to balance out the organic material. When cacti are exposed to prolonged periods of dampness, their roots become susceptible to fungal and bacterial infections. These pathogens attack the roots, impairing their ability to absorb water and nutrients.
What happens to cacti if they have root rot?
If a cactus has root rot, it will exhibit several signs of distress. The most noticeable symptom is a squishy, discolored base that appears to progress up the cactus. The affected cactus may also develop a foul smell at the impacted site. Over time, the cactus may become overwhelmed by the root rot and eventually die if it is left untreated.
How to treat a cactus with root rot?
Early detection and prompt action are crucial in treating cactus root rot. Here are the steps to take:
Most of the time, it's best to just abandon the stock
By the time you are noticing the rot, it is likely too late to treat it. Therefore, you will need to completely cut above the line of disease and abandon the diseased root stock, preserving only the part of the cactus that is still fresh & healthy. Make sure that there are no areas of rot on the cutting that has been taken, because the rot will continue to spread.
However if you happen to catch it really early then:
1. Remove the affected cactus from the soil
Gently uproot the cactus and carefully remove any soil clinging to its roots. Inspect the roots for signs of rot, which may appear brown, slimy, or foul-smelling.
2. Trim the affected roots & treat with anti-fungal
Using a clean, sharp knife or pruning shears, trim away any soft, decaying roots. Make sure to cut above the infected area, leaving only healthy tissue. Oxidate, or Zerotole which is chemically the same as Oxidate (but cheaper) is an anti fungal that acts kind of like chemotherapy for plants. Both of these require research and proper application. Please be sure to follow instructions and it's best to err on the side of less than more if you are new to using these products.
3. Allow the roots to dry
Place the cactus in a well-ventilated area and allow the roots to dry for several days. This step helps prevent further infection and promotes the growth of healthy roots.
4. Repot the cactus in fresh soil
Choose a well-draining potting mix specifically formulated for cacti and succulents (more on this below). Plant the cactus in the new soil, making sure the roots are spread out and covered.
Prevention is the key
To prevent future root rot, it is essential to adjust your watering practices and maintain a good balance of inorganic and organic material.
Finding the right soil composition depends on the zone in which you live. A good baseline to go off of to start are:
Dryer climate: 2/3 organic soil and 1/3 inorganic (lava rock, perlite or pumice etc)
Wetter climate: 50/50 split
By following these steps and providing proper care, you can increase the chances of saving a cactus affected by root rot. Remember, prevention is always better than cure, so be mindful of your watering habits and the moisture levels in the soil. With the right care, your cacti can continue to thrive and bring beauty to your space.