Propagating cacti from seed is not a difficult or daunting task. It is simply a task that requires a few necessary components. These components are the seeds, a container to plant the seeds in, potting soil, a glass or plastic cover for the growing container and a spray or mist bottle with water. You will also eventually need a larger container to transplant the young cacti plants into when they are large enough to move from their first container. Fungicide and fertilizer may be needed.
The cacti seeds can either come already prepackaged or they can be fresh. If you are propagating cacti from seeds that are fresh, meaning that they come from the berries produced by cacti flowers, they must be dried. If you have just been given cacti berries, do not panic, these berries will actually be cacti seeds as soon as they are dry. To dry these berries, simply set them out, spread thin, on a flat surface that they will be easily removed from, and where they can get air ventilation easily. Then place this object with the cacti berries on them where they can dry, but not where they will have a chance to get too hot. Direct sunlight will not work and attempting to dry them in an oven will not work. You can, however, speed the process using a fan to circulate the air. Cacti seeds are viable for many years, so do not be afraid of drying a lot of cacti berries.
When propagating cacti seeds the proper potting soil is an important factor in the equation. This would be a potting soil made up of one part crushed gravel or perlite, which is volcanic glass, to three parts regular potting soil. Another formula for cacti potting soil is one part sand to three parts perlite or vermiculite, which expands when heated. Both of these type potting soils will allow the water to drain through so the cacti do not get to much water.
The container needed to propagate cacti seeds in is pretty simple as well. If you are planning on propagating a lot of cacti seeds simply use a standard nursery flat. Also, if the cacti seeds are from several different species of cacti, mark the flat in the location where the different seeds are located. Using the special mixed potting soil, plant the dried seeds one-quarter of an inch deep in the nursery flat. After the seeds have been planted, spray or mist them with water. Next, you will use the clear glass or plastic to cover the flat of cacti seeds so the moisture will be kept in. The flat with the cover should then be placed where there is quite a bit of sunlight. Allow the potting soil to dry between watering, this will prevent mold and other diseases from killing the cacti sprouts. Fungicide can be applied to the cacti sprouts if it is needed. The potting soil in the flats will need to be kept at a temperature between 70 and 75 degrees Fahrenheit and can be accomplished using an electric heating pad or an electric light.
When your cacti sprouts are well established the cover can be removed. Wait a few days, then transplant the individual sprouts to their own pots. These pots should have a hole in the bottom for drainage and the same potting soil used for propagating the cacti seeds should be used in the transplanting of the young sprouts. These newly transplanted cacti will be watered even less than they were when they were in the flats. Fertilize them now if they need it.
