(In the East of Scotland)
By Allan Weepers

To grow cacti and succulent plants, a basic understanding of their native growing conditions is useful. This group of plants grow in arid (dry) areas of the world where regular rain is not guaranteed, so the plants have adapted to store water to preserve life during these dry periods. Therefore, in cultivation, a dry period is required, usually October to March depending on temperature. The lower the temperature the longer the dry period and the warmer vice versa, never going below 3 to 4 months of “drought” minimum temperature of 5-7° C.

Echinopsis cv New Dawn (short spine)

The arid areas of the world have little growth, therefore not much-decomposing vegetable matter, resulting in poor soil with little organic content so we should add a quantity of sharp sand, grit, gravel or expanded clay to our growing medium. This also aids drainage allowing us to water freely in the summer months. A top dressing of gravel is also recommended giving super drainage in the top of the pot, meaning that the bottom of the plant does not sit on wet compost which causes rotting. It also looks good.

The other effect of little growth is limited shade so cacti and succulents have adapted to high light levels producing “wool” to shade themselves or dense spination, both acting as a “sunblock”. Thus by giving our plants maximum light, we can achieve well-balanced growth. Care is required in early summer after months of dull winter light to ensure plants do not burn. This can be achieved by netting or paint-on shading. Keeping plant bodies dry stops patch burning by magnified light through water droplets.

Mammillaria guelzowiana v. robustior
Mammillaria guelzowiana v. robustior

The containers we grow our plants in can be clay (my preference) or plastic but should be large enough to accommodate all the plant, including spines. Thus neighbouring plants cannot be damaged.

Compost – (Update)
As Peat is being phased out, alternative growing mediums are becoming available using coir, bark, wood fibre, and digested and recycled material.
I am currently trying the following mix after some experimentation ensuring that it dries quickly after watering:
1 part bark-based compost
1 part John Innes compost
1 part coarse Vermiculite
1 part grit
Many growers also add expanded clay available as cat litter (not the wood fibre type).

Rebutia cv JessicaRebutia cv Jessica

Top Dressing
Top dressing can be harling, granite chips, pea gravel or grit. A reasonable layer is recommended
Last but not least, chemical additives are required for growth and health. A high potash food is recommended such as phostrogen or tomato food. Alternatively, Chempak supplies specialist food.

Pest Control
Although many pests do not affect cacti and succulent plants, some do. Red Spider and Mealybugs are the main ones. Mealybugs on the plant body may be removed using cotton buds soaked in methylated spirit. However, root Mealybug is more difficult and quarantining new plants to stop introduction is the best deterrent.  If a plant has root Mealybug, remove all compost and wash the roots.  Removing all the pests may seem drastic but works.  For Red Spider, one remedy still on the market is ‘Hotbox Sulfume’ which vapourises sulphur which the red spiders dislike.  Regular use seems to be effective.

Now that you know how to grow succulent plants, all you have to do is choose the ones you want, remembering that some require a higher minimum temperature than others 40 or 50°F  (4 – 10°C) as mentioned above. Using a proper Cacti Nursery, you can check this out. However, using Supermarkets and DIY Stores you cannot.  A rough guide is tall cacti and all succulents with swollen roots (turnip-like with shoots out of the top) and Melocactus require a higher temperature.

Greenhouse view Rebutias

So now you have bought your plants, here is my quick reminder

WATER in Summer, once a week, twice if really hot
FEED one week in three
DRENCH with insecticides annually
REPOT when the plant outgrows the pot – using open compost
REMOVE DEAD FLOWERS – do not allow them to stay on the plant and rot.

But most important of all – HAPPY GROWING.