Propagation from seed
The seeds are quite easy to germinate and grow. Their main requirements consist of high humidity levels, free-draining soil mix, and enough (but not too much) water, light, and nutrition. There are a number of commonly-used methods that satisfy these requirements and the choice of a particular method depends mainly on the scale of the cultivation operation.
For soil, use coarse sharp sand (sieved river sand). Some people also find coir or peat, or mixtures, to be effective. The soil can be sterilized by cooking it in an oven on high for 1–2 hours. Sterilization will be most effective if the sand is moist. If one is available, an autoclave would also be useful at this point.
Some people find sterilization to be unnecessary. This may depend on other factors. The soil is placed into trays (which can be sanitized with bleach beforehand if desired) and the seeds planted into it (when the soil has cooled). The seeds should be only just below the surface (i.e. two or three sand grains over them). The trays now need to be kept in a humid environment. This may be achieved by the use of plastic bags, glass plates, or greenhouses, depending on scale. About 25 °C. is a good temperature for germinating the seed, with 33 °C during the day as a maximum temperature and 15 °C as a nighttime minimum temperature.Seeds usually germinate within two weeks to a month, but sometimes come up after several months.
The seedlings stay in the humid environment for several months. During this time they must be continually checked for water and nutrient requirements, and fungal pathogens. Ensure the soil stays moist, but not overly wet. Nutrients can be provided with a liquid fertilizer at 1/8 strength whenever growth rate slows down. Fungi can be killed with a sulfur- or copper-based fungicide. There have been some reports of seedlings responding negatively to these treatments; so be very cautious with the amount used. There is some evidence that garlic is also an effective fungicide.
If germinating seeds in cold weather, a heat mat and fluorescent light can be used. These should be set on a timer to mimic normal diurnal temperature cycles for germination but can be left on permanently for faster growth once all the seeds have sprouted. One good method for growing cacti seedlings using this setup is to germinate them in late winter and have them ready to go outside by spring as temperatures and light levels are increasing.