Most cacti and succulents come from dry areas such as steppes and desert. High temperatures and low rainfall force plants to collect and store water to survive long dry periods. They are very adaptable houseplants and will thrive in a range of indoor conditions. In fact, they are very difficult to kill, and if properly potted they require little maintenance to thrive. Additionally, some cacti and succulents bear extraordinarily beautiful flowers.
Cacti and succulents need warm temperatures and bright conditions for growth and flowering. Prolonged periods of low temperatures can lead to fungal diseases and stunted growth so they should be placed in the warmest and sunniest part of the house.
Bright conditions are required – these are among the few plants that can thrive on a south facing windowsill all year round. In the middle of the summer, however, light through a window may result in scorching so check regularly and move around if you notice any scorching from too much light. East or west facing windows can be good enough, too.
Although they can withstand long periods of drought, cacti and succulents will need regular watering especially during the growing season. Allow for the top part of the growing medium to dry between watering, but not too much as this will inhibit growth. Water from the top of the pot. Regular watering is especially important during flowering to prevent premature drying of the flowers.
In their natural environment cacti and succulents absorb nutrients and water from dew or mist so they will benefit from regular misting with water, or a specialist nutrient mist which provides nutrients at the same time. The best time to mist a cactus or succulent is in the morning. Avoid misting in cold weather/during the winter.
Cacti and succulents will respond to regular feeding which will promote healthy growth and flowering. Use a fertiliser specifically formulated for cacti and succulents, at the recommended rate with every other watering during the growing season and occasionally during the winter.
Most cacti and succulents will flower once a year – in response to high temperatures and bright conditions (Christmas cactus is an exception and will flower in response to short days and lower temperatures). Unfortunately, the house environment is not warm and bright enough to enable some species to flower.
Cacti and succulents need repotting every 24–36 months, or if the condition of the old soil is poor. For best results plants should be repotted early in the year, just before the new spring growth starts, but they can be repotted at any time in the summer. If not repotting, it is a good practice to replace the top part of the growing medium (without removing any roots) with fresh medium every year.
When repotting cacti or succulents it is important to use a pot with an adequate number of drainage holes and a free-draining growing medium specifically for cacti and succulents.
Start feeding with a specialist fertiliser six weeks after repotting – this will encourage healthy growth and flowering.
Problems and Solutions
Shrivelled stem or leaves
Check the growing medium. If it is too dry the cause is very likely to be under watering. Water immediately and adjust the frequency of future waterings accordingly.
White ‘threads’ on leaves
White fluffy insects in plant crevices
These are most likely mealybugs. Remove with a cotton bud dipped in methylated spirit and wipe the leaves or stem clean regularly to prevent an infestation (assuming there are no spines in the way).
Brown or mushy parts
This is most likely due to excess water. Cacti and succulents need to dry between waterings, and to receive plenty of sun light. Too much water makes the tissue soft and easily attacked by fungi.