Opuntia from seed can be either very easy or extremely frustrating. The reason for the 2 extremes is connected to the dormancy of the seeds which needs to be broken correctly so that the seed germinates when you want it to and not when it feels like it.
In nature Opuntia fruits are eaten, the seed passes unharmed, except that the chemical coating in the seed case has been removed by the process. Now it is possible to buy chemicals which you can soak the seed in to recreate the process, however, there is a much simpler way.
Place the seeds in a ceramic cup (this is important as plastic ones might cause harm to come to the seed). Pour on sufficient BOILING water to just cover the seed ie no more than a few millimetres but sufficient to cover them completely. This treatment breaks down the chemical inhibitors and the seeds survive the contact because you use a ceramic cup which conducts the heat away and very little water – all of which minimises the risk to the seed. After 5 – 10 minutes top up the water to 3 – 5 cm with warm water and then leave to soak for a few days changing the water every 12 hours or so. It is important to change the water as this flushes away the chemicals we are trying to remove. Don’t let them dry out, or else you will allow the inhibitors to soak back into the seed.
Now sow the seeds – covering them with their own depth of good quality compost. Water them and now place somewhere warm, close and bright. Sealing the pot in a plastic bag and placing them in a propagator will be best. They need a temperature of 22 – 35 Deg C to germinate and sunlight, so do not place them in the airing cupboard.
Germination will commence in 7 – 10 days and will continue for quite some time. The seedlings look nothing like a prickly pear; they look more like cress with fleshy leaves. Eventually the pads will start to form from the centre of the seed leaves and a more recognisable plant will emerge.
Pot them up when large enough to handle into cactus compost. Do not throw away the pot though as I have seeds germinate as much as three years after they were sown (these are the ones that the treatment did not work on).
Opuntia from seed can reach flowering size in as little as three years from seed. Some types will be hardy, others will not. Most can be identified out of flower providing you knew what you had to start with.
