 
Quick Tips
 Plenty of bright light e.g. sunny window ledge.
Water weekly in hot weather, fortnightly or less in cool weather.
Never leave standing in water for more than 2 hours.
Pot up in a gritty free-draining soil-based compost.
Use any type of pot with drainage holes.
A cold-dry Winter promotes flowering of some cacti.
Whatever the size of your collection of succulent plants, I hope that you find the following hints and tips useful. This information is of a general nature, based on the accumulated experience of many growers. However, the owner of this page cannot accept liability for any plant loss, or damage, or personal injury arising from use of this information.
The best way to get information about growing cacti and succulent plants is to join your local Cactus and Succulent Society, where advice is freely available from other members. Specialist societies exist for Asclepiads, Epiphytic Cacti, Euphorbias, Haworthias, Hoyas, Mammillarias, the Mesembryanthemum group of succulents, Peperomias and Sedums.
 Pots & Containers
for Succulent Plants
Two types of pots are available, clay or plastic. The choice is mainly a matter of personal preference. Plastic pots are lighter, cheaper, require less watering and are easy to keep clean. Clay pots can provide stability for tall plants and can mitigate the effects of over-watering, but their accumulated weight requires strong greenhouse staging. Whichever type of pot is chosen, it must have a drainage hole and the bottom should be lined with several pieces of broken clay pots or large clean gravel to assist with drainage.
Many cacti and succulents have fibrous roots and do not require or use the full depth of a standard pot, and half pots or pans are more suitable. Putting a shallow rooted specimen in a deep pot is counter-productive as the soil below the reach of the roots will stay wet for prolonged periods after watering and may become stagnant.
Those species which have tuberous or tap toots often require a deeper pot and will probably grow better in a standard pot or even a "long tom" if you can find one.
Bonsai pots can look very effective with caudiciform plants where the caudex (a swollen root or lower stem) is raised up above the compost. Finally, some cacti and succulents are native to limestone areas and often seen growing in cracks in limestone boulders. Such lime-tolerant plants are suitable for planting in a block of tufa and can look very effective as an alternative to alpines.
Soil Mixtures
for Succulent Plants
Many different types are available commercially, ranging from John Innes soil based composts to peat based and recycled garden composts. Add horticultural grade sand and grit to make the mixture porous; the final compost contains between 30% and 70% grit. You may have to experiment a little to find the best proportions of compost, sharp sand and grit for your growing conditions and using locally available materials.
Many plant nurseries grow and sell succulent plants in peat based compost. The first thing I generally do with my new plants is to repot them into my own loamy mixture. Repotting provides an opportunity to examine the condition of the roots.
Peat based composts appear to encourage root mealy bug compared with soil based compost, and many growers feel that Lithops (living stones) grow atypically in peat-based media. I have personally moved away from growing in peat based compost in favour of soil-based mixture (see opposite) except for plants that clearly need to grow in peat e.g. carnivorous plants. Coir fibre is becoming a fashionable alternative to peat, but is said to break down too quickly for use with slow-growing succulent plants like cacti.
Some epiphytic plants like Hoyas grow naturally in organic detritus in the forks of tree branches. I find that 'difficult species' often grow better in a free-draining mixture containing a high proportion of bark-based orchid-seedling compost with a small amount of soil-based compost rather than in 100% soil-based compost.
My own mixture:
As an example, my own potting mixture is based on sieved compost made from vegetable kitchen waste and leaves, weeds and other waste from the garden. This material accumulates and decomposes in a large green 4 ft tall plastic composter, obtained from the local council for a small fee.
Unlike peat, and possibly because of a small soil mineral content, this compost doesn't seem to encourage sciarid fly larvae and root meally bugs.
To the sieved compost is added about a third by volume of equal amounts of sharp sand and 2 mm flint/quartz grit which I also use for top dressing. Measuring with any convenient container that comes to hand or even by handfulls is sufficiently accurate. So this recipe amounts to four handfulls of compost to one of grit and one of sharp sand.
For species known to come from limestone habitats, I substitute ground dolomite of lime for the sand. More grit is added for "difficult" species.
The whole mixture is then packed into a stainless steel cooking container, sufficient rainwater added to ensure a moist consistency and the sealed container heated in an oven (e.g. 250°F for > 2 h).
This treatment is essential to kill insects, larvae, eggs and seeds which may be present in any garden-based product but leaves some of the beneficial soil microoganisms, particularly those that form spores.
| Grit - mineral particle grades |
| Clay | | 0.002 mm |
| Silt | | 0.002-0.06 mm |
| Fine sand | | 0.06-0.2 mm |
| Coarse sand | | 0.2-2.0 mm |
| Gravel | | 2.0 - 20 mm |
| Pebbles | | 20 - 60 mm |
| Cobbles | | 60 - 200 mm |
| Boulders | | 200 mm |
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Soil pH
. . . more about
soil pH
Most cacti and succulent plants prefer a slightly acidic compost (pH6). If in doubt, this is the best choice for most species, but also avoid watering with strongly alkaline tap water. Simple, affordable pH meters are sold in many garden centres.
Some species e.g. Echevierias really hate lime and are probably suited to a peat-based compost. Others e.g. Ariocarpus fissuratus, Echinocactus horizothalonius, Escobaria tuberculosa always seems to grow on limestone in their habitat and may appreciate a proportion of ground limestone or dolomite of lime in their growing medium. Still other plants e.g. Geohintonia are noted for growing on nearly pure gypsum cliffs.
Ground limestone is calcium carbonate with a mild alkaline reaction neutralising soil acids.
Dolomite of lime is a mixture of calcium and magnesium carbonates with a mild alkaline reaction.
Gypsum is calcium sulphate, neither acidic nor basic.
Garden Lime is calcium hydroxide and has too strong an alkaline reaction for use in potting mixtures.
Repotting a prickly customer
Ideally, succulent plants should be re-potted every year to provide fresh compost and room to grow. This is also an ideal time to inspect the roots for diseases such as root mealy bug.
A good way of handling spiny cacti or spiny euphorbias during repotting without breaking the spines is to wrap a roll of newspaper or paper towel round the sides of the plant. This may be kept in place if required by elastic bands or a wire twist tie. If the spines become entangled, wetting the paper will make it easier to remove, and small bits can be taken off the spines with tweezers. 'Old hands' often handle plants with bare hands during repotting by distributing the weight on the hands between as many spines as possible. However, this is not recommended with Opuntia sp. as the fine spines (glochids) will break off and become embedded in the skin, or with Mammillaria species with 'fish-hook' spines that tend to catch in the skin.
To re-pot, invert the plant and tap the rim of the pot against the bench or with a piece of wood to loosen the pot from the compost. Inserting a piece of cane into the hole in the pot may help this process, but beware of damaging plants with fleshy or tuberous roots. If the plant is in a plastic or other flexible pot, squeezing the pot gently may help to loosen the root ball. As a last resort, it is better to break the pot to free a compacted root ball rather than damage the plant.
Remove the pot and clear away the old compost from the roots, keeping an eye out for pests. Use a thin stick or plant label to tease out the roots and remove old soil. If you see white fluffy patches in the soil and tiny insects, similar in shape to woodlice, but about 2 mm long these are root mealy bugs. If you find any pests, remove or wash off as much soil as possible, and soak in systemic insecticide. I used to use a formulation containing dimethoate but this is now unobtainable. One based on imidacloprid which is less toxic to plants and people was very effective, but also hard to come by. Newer Neonicotinoid insecticides can be tried but seem less effective to me.
Repot the plant into a new pot, which should be a little larger than the old one (perhaps 1 cm extra all round) if the plant has grown to fit its old pot. Replace fairly dry new compost around the roots and allow the plant to rest for about two weeks before watering to allow broken roots to heal.
Handling Euphorbias
The Euphorbiaceae comprise a fascinating group of succulent and non-succulent plants, with a wide range of growth forms and sizes, and are well worth growing. However, the milky latex characteristic of plants in this group is very poisonous and should be treated with respect. Euphorbia latex should never be allowed to come into contact with the eyes and any contamination should be washed off the skin immediately. It is a good idea to make a habit of washing one's hands with soapy water immediately after handling or re-potting any Euphorbia species.
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