Propagation of cacti or succulents from seed is a relatively easy and inexpensive way of obtaining plants, many of which may not be readily available through commercial outlets or garden centres.
Dinteranthus puberulus – 8 months
Seed may be obtained from your own plants, swaps with other enthusiasts or from membership with such as the British Cactus and Succulent Society, the Mammillaria Society and the Mesembryanthemum Study Group.
Astrophytum after 12 months
Time to sow
For summer-growing plants, all cacti and many succulents, seed sowing is best done early in the year. If you have a heated propagator, then the seed may be sown as early as February, otherwise, it is best to wait until May when the weather has warmed up. Seed can be sown in a seed tray or in BEF 2” or 2½” pots – whichever you use, make sure that the seeds are clearly labelled as young plants are often difficult to identify and it is all too easy to mix seeds up. For winter growers such as Cononphytum, Cheiridopsis, and Gibbaeum (to name a few) better results are obtained by sowing the seeds in August or September and nurturing them until the following year. Whenever you sow, make sure your seed tray or pots are clean.
Seedlings in 2″ pot
Compost
For compost, there are two schools of thought – the first is a mix of equal parts John Innes No 2 (sieved to remove debris) and small grit; the second is to use 1-3mm pumice as a completely mineral substrate. Most of the composts on sale at garden centres are now peat-free and this may require some experimentation before you decide on a brand that suits your needs. Pumice is initially more expensive but can be washed and reused.
Sowing the seeds and germination Once your pots are prepared, fill to about 1cm from the brim with compost and gently tap down.Scatter the seeds evenly over the surface and cover with a thin layer of compost. Water the pots or seed tray from below until the surface of the compost is damp and then place inside a heated propagator, which should have a clear top cover to allow plenty light, and set the thermostat for about 21-22 0 C. Germination should generally be within two-three weeks for most seeds, although if they do not show within that time be patient as some seeds can take considerably longer. If you are not using a propagator, then place the damp seed pots or tray inside a clear polythene bag; place in a warm location with plenty light (although shield it from direct sunlight) and wait until germination. If you are sowing seeds in pumice, then dampen the pumice before sowing the seeds and then follow the same procedure as for compost-sown seeds. Pumice-grown seeds tend to germinate slightly faster than compost-sown seeds. For both methods, the key to successful seed-sowing is sufficient warmth and plenty light – trying to germinate seeds in a dark airing cupboard is unlikely to work.
Watering Once the seeds have germinated, they should be kept adequately watered. Try not to let the compost dry out entirely and always water from the bottom to prevent seedlings being disturbed or, worse still, being washed out of the compost by heavy overhead watering. At this stage, watering will probably be required every 7 – 10 days. Do not let the seed pots become water-logged or the seedlings are likely rot. Pumice drains very quickly and watering may be needed every 3 – 4 days. If they are still in the seed pots when winter arrives, stop the watering but give the occasional spray to prevent the plants drying out completely.
Transplanting Once germinated and growing well, the temperature in the propagator can be reduced and the seedlings should be given ample light to prevent them etiolating – becoming thin and drawn. A south-facing windowsill, conservatory or greenhouse should provide sufficient light. They can safely be left in their seed pots for twelve months or until such time as they are large enough to handle without damage to the plants or the root structure. Depending on how many seeds have been sown, a little thinning out may be necessary, although some plants grow well when in company. Once the pot is crowded and plants are jostling for space, then it is probably time to transplant them. As young plants are easily bruised and damaged, care is needed when moving them into individual pots and a pair of tweezers is a useful tool in helping to move them.
After-care Once settled in their new pot, take care to ensure they receive adequate water and light (plants gown in pumice may require more frequent watering). You may need to provide some shade for the young plants in the height of summer. Direct sunlight can burn the plants and leave brown scarring, from which the plant may take a long time to recover. Keep a lookout for pests – mealy bugs and red spider mites are partial to young plants and tackle any as soon as you see them. Having done that, you can hopefully enjoy your plants for many years to come.
