A number of cactus species are easy to grow from seed. Here are details on some of these.
Mixed cactus seed
Thompson and Morgan has a special mix of easy to grow species. Recommended for greenhouses and as indoor plants, these are generally hardy in warm regions of the country. The height ranges from four inches to two feet.
In general, these can take as little as five days to germinate. However, seeds of some species can take several months. For best results, keep seed trays or pots at a minimum of 75 degrees Fahrenheit.
Hedgehog cactus (Echinocereus spp.)
Hardy to about zone eleven or so, about 14 species of hedgehog cactus are in cultivation.
Some of these are fairly easy to grow from seed. Quick flowering, the blossoms come in a range of colors. The plants range from two inches to a foot or so in height.
The seeds will sometime sprout in about a week. However, they can take four months or so sometimes. For best results, keep the pots or seed trays at least 70 to 75 degrees Fahrenheit. They’re usually planted in the spring.
Thompson and Morgan has a hedgehog cactus seed mix as do some other seed companies. In addition, the seeds of several specific species are available. There is also a mix of different varieties of Echinocereus pectinatus.
Easy to grow from seed, these are hardy to about zone 11. At least 30 species are in cultivation.
The seed is usually planted in late winter or early spring. Best results are achieved between 65 and 75 degrees Fahrenheit. The seeds can germinate in about a week. In some cases, it will take three or four months.
Thompson and Morgan has a mammillaria seed mix. The Thompson and Morgan catalog lists some of the species in its mix.
Prickly pear (Opuntia spp.)
Considered to be among the fastest growing cacti, this is easy to grow from seed. The seeds often germinate better if they’re soaked prior to planting. The seeds of hardy species often benefit from a cold treatment before planting. This can be done by planting them outdoors in the fall or by refrigerating the seeds for a month or so.
The seeds can be sown in the early spring indoors or in a greenhouse. Use a standard cactus mix. Set the seed tray or pots in a bright spot.
Several seed companies sell prickly pear seed mix. Seeds of Opuntia ficus-indica are also available. J.L. Hudson sells seeds of various individual species of prickly pear.
Some species of prickly pears are hardy enough to grow outdoors in some regions. In other cases, they’re best grown indoors or in greenhouses/conservatories.