Cacti are usually on the windowsill of people who have little time for plant care. But there are also rules for cacti that should be observed. Mistakes can be made, especially when repotting.
Cactus soil can store a lot of water
When is a cactus repotted?
Cacti are relatively undemanding. They grow very slowly, it is enough to plant them in a different container every two to five years. At the latest when the cactus has grown very large or roots are growing out of the pot, it needs a new home.
The right soil for cacti
Cactus soil must have various properties in order to thrive:
- Structural stability so that the plant has a footing
- crumbly texture
- Air exchange possible
- good water retention
- nutrient richness
- pH at 5.5
Commercially available or your own mixtures can be used.
The standard mix
It contains mature, three to four year old compost that has been sanitized by sterilization. There is also peat, which has good air and water retention. Fibers made from bark, wood or coconut can also be used instead of peat. Crumbly lava, expanded clay (19.73€) or pumice are also added. The materials keep the floor airy and retain water.
Good potting soil can be used as a basis for the standard mix. It is mixed with 20% lava or expanded clay and 20% pumice.
The mineral mix
Some cacti require an extra portion of minerals. Here more lava or expanded clay is mixed into the potting soil, plus pumice, river sand and some clay or zeolite (volcanic mineral).
The repot
When repotting your cacti, proceed as follows:
- Give up watering for a week.
- Get sturdy gloves to protect against the thorns.
- Carefully remove the cactus from the pot.
- Shake out the roots and loosen them up with a wooden stick.
- If the cactus has rotten spots, they must be cut out.
- Leave the plant to air for a few hours, up to two weeks in case of rot (the wound should be dry)
- Prepare the new pot and place a drainage layer of broken shards, gravel or expanded clay over the drainage hole.
- Fill in soil and place the cactus in its new environment.
- Water the plant only after a week.
- Avoid direct sunlight for about three weeks.