Cactus and Succulents


There are probably well over 20,000 different plants that come within the scope of Cactii and Succulents, below is a brief guide to some of them.

Contrary to belief that cactus require hot dry conditions is not quite correct!

Any frost-free, sunny place will satisfy the majority of cactii, provided they are kept relatively dry in winter.

A Collection of Cactii

Similarly, a greenhouse, though desirable, is certainly not essential, since many plants will thrive and flower regularly on a sunny windowsill.


Most Cacti and Succulents are quite easy to grow and care for, and come in a multitude of interesting shapes, sizes, and spine forms.

Many of them with careful cultivation will produce magnificent and brightly coloured flowers.

Once a plant is old enough to flower it should do so every year, generally in the spring or early summer, Christmas cactus, Echinopsis, Epiphyllums, Lobvias, Mammilarias, Notocactus and Rebutias are particularly good for flowering.

Many Cactii will flower when quite small, particularly Gymnocalyciums, Mammillarias, Notocactus, Parodias, and Rebutias.

Some plants will flower more than once during the same year, plus many of the above named plants will flower within 3-4 years old from sowing seed.

Astrophytum ornatum
Parodia leninghausii

Mammillaria geminispin

Mammillaria hahinana

Example of the seasonal stages / growing cycle of a Thelocactus

Germinated seedlings (year 1)
Pricked out (year 1)
Growing on (year 1)
Growing on (year 1 / 2)

Various stages of the flowering cycle (year 2 onwards)

Flowering period about to end (year 2 onwards)
Seed Capsule (year 2 onwards)


Succulents come from 22 different plant families and differ from cacti in so far as they generally have leaves instead of the spines / hair which are the characteristic of a true cactus.

They come in many shapes and sizes, and the plant bodies can vary widely in colour.

Although more diverse in their requirements (some are winter growing or flowering) most require similar treatment to the cacti, for example: they generaly need less sun, more water and are rather more vigorous in their growth.

Unfortunately with the winter growing types, light levels in the UK are normally too low to allow much natural growth.

Growth made during these months will often be weak and slender and greater care should be taken when watering.



Lithops: or Living Stones should be planted so that they just emerge above the level of the compost and they grow best in a sunny position.

They respond well to a weekly watering and a monthly balanced feed.

Their large daisy like flowers in white or yellow are produced in the autumn up to November or December.

After this they should be given a rest as for the other types of succulents.

In spring, when they begin growth again, the outside segments of the stem die off and are replaced by new growth from the centre.


Epyphillum hybrids are grown for their huge, spectacular flowers, which come in a large range of colours.

Their ancestry can be traced back to epiphytic cactii, rooting in pockets of dead vegetation in the branches of trees in tropical rain forests.

Because of their origins, they need more water than the terrestrial cacti, and they prefer a shadier position, such as under the greenhouse staging, or on a fairly light window sill.

They will also benefit from liberal feeding with high potash fertiliser in the growing season.

Epyphillum hybrid

Ideally they should not be kept in areas where the temperature can fall below 4°C (40°F), although some are more tolerant and will withstand temperatures down to 3°C (35°).

Aporocacti, Aporophyllums and Selenicereus require similar treatment to the epiphyllums.

All of them benefit from more sun, and need plenty of water and feeding during the summer months.


Christmas Cactii (Schlumbergera) does well as a house plant, and should be kept shaded from prolonged direct sunlight, or grown under the greenhouse staging in summer/autumn to induce bud formation.

Watering: they should be watered just before the compost completely dries out, and fed every two weeks with alternate high potash and balanced fertiliser liquid feeds during the growing season.

The compost should never remain saturated for long periods.

They are tolerant of low temperatures, down to 3°C (35°F) for short periods.

To flower in the winter months, keep them above 8°C (45°F)


Some of the colours, e.g. whites and yellows may develop pink flushing at lower temperatures, so temperatures of 13°C (55°F) plus is better to get truer colours.


Cacti and Succulents require a porous compost e.g.

Sowing compost:

Potting Compost:


1 part compost,

1 part loam,

2 parts sharp sand,

3 parts grit.

* Measured in parts by volume.

1 part compost,

1 part peat,

4 parts loam,

2 parts sharp sand,

5 parts grit.

Sieved potting compost

Sieved peat

Loam or sieved home made compost

Sharp / River sand, agricultural grit or expanded clay aggregate.


Most plants are easy to grow and are quite tolerant to low temperatures 4°C (40°F) if kept fairly dry.

Like most plants they will benefit from good ventilation but not draughts.


Plants require a nice bright situation at all times and will grow happily in a south facing window.


Over-watering is the main cause of cacti dying, and winter is the most likely time, i.e. when the plants have stopped growing and the evaporation from pots is slow.

It is recommended that during the winter all cacti (except Christmas Cacti) should be kept reatively dry from around November (Week 44) until April.

Too much water at these low temperatures may cause them to rot.

To start up again a little water should be given in April (Week 16-17), and the amount increased gradually, until the plants are being watered once or twice a week by the summer.

Water and feed during the spring and summer, allowing them to dry out between each watering.

In the autumn watering is gradually reduced again, giving them just enough water to keep them from shrivelling up.


Sow seeds in spring (Week 16-18) at a temperature of 21°C (70°F)

Depending upon variety germination can be a bit erratic.

On average germination should take about 1-4 weeks.

Germinated Seedlings

Week 25:

Prick out plants if large enough to handle into 50mm (2") pots or cells.

Offsets can be detached in summer (Week 25-28) and set in grit sand.

These should root within 2-3 months when they can then be potted on into growing medium described above.

Week 37-40:

Collect seed.

Seed Capsule


The main pests of cacti and succulents are mealy bugs and these may occur on the roots, stems or leaves.

Although mealy bugs are unlikely to kill the plants, they do look unsightly.

They can easily be eradicated by the use of systemic insecticide.

Mealy Bug

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