Raising cacti and succulents from seed
Great satisfaction and pleasure can be gained from growing your own plants from seed and in watching them pass through the various stages of their development, until the day that their first flower appears.
If you are lucky this will take about 18 months, but 2 or 3 years is more usual and some types will take even longer.
Choose clean plastic pots, about 3 inches in diameter, for your sowings. Loosely fill them, almost to the top, with a John Innes seed compost.
Use a fine sieve to sprinkle on the final quarter inch or so of compost. Now water the pot using a watering can with a fine rose on it until the entire potful of compost is wet. Allow a few seconds between waterings so the water has time to sink in and does not wash the compost out of the pot. Alternatively, you can stand your pots in a container of water so that they absorb the water upwards through the compost (see photo below).
After settling, the compost will be a short distance below the top of the pot. Insert a plastic label into the pot so that it protrudes a good way beyond the top of the pot.
Sprinkle your seeds evenly over the surface of the compost. If you have a sprayer available (a small hand-type is ideal), wet the seeds with a fine spray of water.
For added protection, a fungicide such as Benlate may be added to the spray as this will reduce the likelihood of your seeds or seedlings being attacked by fungi. Cover the top of the pot with a transparent polythene sandwich bag and secure it with an elastic band around the rim of the pot. The label will prevent the bag from collapsing on to the seeds.
Germination cannot take place unless the compost remains moist, and the seedlings need protection in their first, most vulnerable weeks, when they are susceptible to attack by Sciarid Fly larvae. Place the pot in a warm place – a temperature of about 70F or 20C is ideal, though some fluctuation in the temperature (plus or minus 10 degrees F) will do no harm.
Darkness is not required for germination, and the best position for the seeds will be well lit, but out of intense sunlight. If the light is strong then cover your pot and polythene bag with a sheet of newspaper laid loosely over the top.
Intense sunlight will make your seedlings go red and their rate of growth will be greatly reduced. If the only warm place is the airing cupboard then use that, though germination may not be as successful, and do not forget to give the seedlings light as soon as they have germinated.
After germination a temperature of 50F or 10C will suffice, but 70F or more will produce faster growth. IdeaIIy, the seedlings should be left in their bags for about two months and during this time the compost should remain moist.
The pots are unlikely to dry out, but if they do then stand them in a container of water until the top of the compost is wet again. It is very important, however, to check the bags regularly, and if there are any problems with moss, fungal growth or stretching of the seedlings towards the light, then the seedlings will be safer if the bags are removed.
After the polythene bags have been discarded, keep the compost slightly moist either by standing the pots in a tray of water for a few minutes, or by gentle watering from above.
Once the seedlings show spines they can be pricked out, but this is best left for a year after sowing unless there is severe overcrowding or some other problem arises. Mild overcrowding seems to have no detrimental effects.
Do not prick out seedlings after the middle of August, it is far better to wait until the following May.
In the Autumn gradually reduce watering and keep the seedlings dry from November until March.
After this, gentle watering may be resumed. During the winter keep the plants in a well lit position and do not allow their temperature to fall below about 40F or 5C.
In fact some seedlings will stand lower temperatures, but experimentation can be dangerous! Once your seedlings have started into growth in the Spring following sowing then you can feel confident that they will reach maturity.