Ceci est une ancienne révision du document !
The first edition of this article was published on the “Cactus Francophone” in 2000. A second edition was published in the magazine “Succulentes” (May 2001). Since then, I received many comments, suggestions and questions. Moreover, I have sown much more, giving me the opportunity to note some further details. Based on the 2nd edition, this 3rd one should give you a closer view.
When catching the virus of cactimania, usually a secondary infection of sowing seed will follow. There are various reasons for sowing seed. First of all, there is the huge choice of genera, species, and varieties. For the most demanding collectors, seed suppliers may offer field collection numbered seed. Seed suppliers often have a much larger selection compared to the choice offered by the plant producers. Secondly, there is the lower price of seed compared to the price of plants. For most of the species, for a packet of 10 to 30 seeds, prices vary between 0,5 and 2 euros. In that way, within a couple of years, one can obtain a nice collection for little money. The third reason is the interest presented by a seedling coming out of the seed and developing its first areoles, its first spines, growing step by step from youth to adult form. A fascinating sight.
Sowing cacti is a little more delicate than sowing tomato or bean seed. Why ? The main reasons for this are their slow growing and their sensitivity to fungus (melting of the seedlings which results in liquefying all the youg plants in a pan within a couple of days). For the first months, waterings should be applied carefully ; on the one hand enough to avoid the seedlings dying from thirst (at this stage, they only have very little stems and very small roots), and on the other hand not too much in order to avoid fungus development. That means daily surveys with a touch of ability and know-how. Sufficient moisture can be maintained and fungus development avoided by using a funcicide. However, that does not stop the development of alga, which theoretically are without danger for the seedlings but which does tend to choke them anyway. (Also, that does not avoid accidents such as forgetting to water or too much watering). In order to avoid all that trouble, there is a method named “baggy”. The idea is easy : the sowing is to be kept in an absolutely closed environment, free from pathogenic agents, and at a constant, quite high degree of moisture. Setting up the baggy requires a minimum of preparation and difficulty, but once the sowing has been done, one can just watch them grow and supply suitable quantities of heat and light.
Soil : As a basis, I use a good quality, fine earth bought in a shop, to which I add vermiculite (expanded mica), perlite or any other draining material, as well as possibly some sand. The important thing is to have an open draining soil. The presence of a quantity of peat does not matter as long as the seedlings are in the baggies. Once out of the baggies, it is better to repot the sensitive species into a more mineral soil.
Treatment : All pots and soil are treated by micro-wave, 15 minutes at full force, and moistened with fertilizer at a normal amount. Use water that is sterile(osmosed, boiled or mineral water). After microwaving, the soil should remain wet enough but not sodden.
Sowing : As soon as the soil and pots are back to room temperature, the seeds are sowed and burried at a depth of their own diameter. Then the pots are put in deep-freeze bags, hermetically closed and placed in an self made “piece of furniture”, nicknamed “Breizh Bed”. No watering whatsoever is necessary as long as the pots are in the “baggies”, i.e. several months. Some people may recommend wiping off the condensation that occurs inside the bags. I strongly recommend this not be done. This condensation causes no harm. And the less often the bags are opened, the less risk there is for contamination. If it is absolutely required to operate inside a bag (for example, seedings arranged in an untidy manner…), all used tools such as forceps are to be sterilized (passed through a flame for instance).
After :When the seedlings are big enough (after 3 or 4 months, but possibly more, up to 1 year) the pots are taken out of the bags and the plants are given the normal cactus treatment of applying times of dryness. I have never noticed any losses due to the sudden fall of moisture degree after seedlings are removed from the baggy, even where very often the seedlings loose volume in a very visible way.
Some remarks :
This is a kind of table-box, made by myself, from material I recovered here and there. It is simply made of 5 wooden boards. 2 upright (100×30 cm) making the sides and in between 3 horizontal ones (160×30 cm). Under each of the upper 2, there is a ramp of 2 fluorescent tubes of 1m50 (58W, but it is not necessary to get them that strong) so as to have about 20 cm between the upper side of the pots and the tubes. Better is to use 2 kinds of tubes, 1 Home light (red) + 1 cool white (blue), in order to get the light spectrum the plants need. They are sold in any “do-it-youself” store or supermarket. There is no need for heating, since the fluorescent tubes already heat very much (almost too much). Correct air circulation is required to keep the temperatures beneath 30° C. In my opinion, ideally one should maintain a temperature around 24 to 28° C at day and lower at night - around 15 to 20° C. A timer gives 12h30 as a day and 11h30 a night. That should be the same as the luminosity during the month of May.