I have a sick Cactus!

(Question)

Hi there,

I have a bunch of cacti in the same pot and noticed that one of them died. I removed the dead cactus from the pot and noticed that the small one at the front of the pot is now starting to dry up as well.
Its been in fairly well lit areas of the house and my house is sitting at around 25 degrees room temp.
I’d love to know how I can fix this, and maybe I need new soil and a larger pot?

I’d really appreciate any insight you may have

Thanks so much

(Answer)

Cactus are wonderful house plants with their odd shapes and beautiful flowers, if we are lucky enough to see them do that. They also need special care, particularly in winter. The Education Extension professor, Don Janssen of the University of Nebraska describes it “intelligent neglect”.

As is often is the case, we kill with kindness. Cactus go dormant in the winter, and do their active growing in the summer months. No fertilizer, and watering sparingly during the winter means a very little, every few weeks to a month. If we water more often, it rots the cactus, as it’s not taking up the water. We just need to keep the plant roots from shriveling.

As well, you’d mentioned that it’s in a well lit condition, at approximately 25 degrees. Your cacti probably did well for years. However, dormant cacti¬† prefer cooler conditions. Next to a cool window often is several degrees cooler than the main house. It will help it stay in a constant dormant state, and possibly trigger the flowering response.

Repotting cactus should occur as the dormancy period ends – as winter is coming to an end, as at that point, you will start watering a little bit more frequently. The pot should be barely larger than the biggest cactus, or the group of cacti about 2 cm from the edge of the new pot. As cacti absorb water during the growing period, heavier pots are recommended, as light, plastic pots can easily tip. Unlike most household plants, cacti do not prefer soil that holds moisture. Any cactus mix from a reputable garden centre would do. If you prefer to make your own, house plant soil mixed 50/50 with builder’s sand is recommended. The sand allows sharp drainage.

Finally, if you can, put your cacti outside in the sun from spring to fall. They are actively growing, and with sun and regular feeding, they will thrive.

If you want to read further about general and winter cactus care: www.lancaster.unl.edu/hort/articles/2008/cactiwinter.shtml

The Toronto Master Gardeners has put together the following Gardening Guide for cacti & other succulents: http://www.torontomastergardeners.ca/index.php/factsheet/growing-cacti-and-other-succulents-a-toronto-master-gardeners-guide/