In this album, you will see many cactus species' seedlings growing and than grafted on Pereskiopsis spathulata.
Growing cacti from seeds isn’t very difficult. However, they need an extra attention than their parents. The seedlings flower in two to four years generally. But for some species, for example Coryphantas and columnar ones, the flowering time gets so many years.
If you have a special propagator, use it. I have not, so I use a home made one.
Here is step by step my seed growing method:
1. The sowing medium is 2-3 mm in diameter washed sand and ready to use peat, 1:1 in proportions.
2. The sowing place is 5 cm plastic pot groups in a large clear plastic box with tightly closed lid. I separate these pots into two to four compartments because the sowing numbers are limited about 5-20 grains. I obtain more space also.
3. Water and spray the compost with a broad spectrum fungicid added ( eg. Captan) fresh water before sowing,
4. Sprinkle the seeds on the soil surface. You can slightly press the big seeds but not bury them, and attention that the hilum is downwards. Do not forget the species name labels.
5. Spray the seeds again with fungicide,
6. Close the lid firmly. This home made propagator must be hermetic to obtain consistently moist soil and high humidity in the environment.
7. Put the propagator in a warm room with bright lightening.
In this case, the room is my working room at home. You can use your greenhouse, if you can obtain these 'must be' conditions.
I use a special, sunlight emitting 2x2x18W fluorescent tubes, (Osram, Fluora). It is about 25 cm in distance to the soil surface and on for 14 hours daily.
The temperature must be around 20-25 C in the system. 20-22 C is ordinary room temperature in winter and sufficient for the seedlings at nights. The day temperature raises to 24-25 C due to greenhouse effect in the propagator, by lamps.
The temperature variation between night and day seems to be beneficial and to some extent simulates habitat conditions.
Note that below 20 C and over 25-30 C temperatures might be harmful to seedlings or seeds not germinate.
The relative humidity in the system must be over 80%. For the first two months we must ensure that the inner surfaces of the propagator is constantly covered by a film or vapour of water.
You can do airing shortly time to time. It may be useful to prevent fungus proliferation. But never allow the soil to dry. It must be wet always until the seedlings reach to considerable size, to 7-8 months old, maybe to a year or more for very slow growing species seedlings. If you notice a mould proliferation, you can spray the system with the fungicide.
When the seedlings are about 1-1.5 years old, you can transfer them to new pots, if you wish to.
Germination takes one to two weeks usually. But for some species it takes more time and even in the same batch, some seeds can germinate weeks later. Just wait !
There are some germinating methods for difficult species' seeds . For this, a procedure is 'Scarification' and helps water penetrate into the seed thus initiating the germination process, in different ways.
A way for large seeds with a hard coat is softened them by soaking in hot water or vinegar, check if the seed coat swells. Also you can scarified them with sandpaper or a file or chipped with a needle.
Another good way for germinating better the seeds by scarification is soaking the seeds in pure sulphuric acid for 10-12 minutes and immediately washed afterwards and then sow.
Treatment with Gibberellic acide (GA3) is another very useful method for persistently not germinating seeds. Soak for one or two days the seeds in 0.5 - 0.7 gm GA3 per liter aquous solution of GA3 ( I use the 1 gram tablet form). Then sow them. It may require more concentrated solution, eg. 1 gm GA3 per liter water. Also it may require for big seeds a mechanical scarification before or after GA3.
I am trying the latter two methods nowadays for the seeds of Eriosyce umadavae, Sclerocactus sensu stricto, Pediocactus, Neowerdermannia, Austrocactus, Opuntia, small Opuntioids likeTephrocactus, and Mahuenia species.
Another method is named 'Stratification'. For some cold hardy species from environments with cold winters may require exposure to cold or even freezing conditions to break dormancy (simulating natural passage through a winter). There are several methods that you can try. For example, to force germination, before or after sowing, enclosed in plastic bags having been moistened beforehand, place seeds or the container in the refrigerator for at least two months at a temperature 4 C. Another way is alternately placing the seeds in the refrigerator and ice compartment over several weeks to simulate freezing and melting cycles.
When seedlings reach a few milimeters, you can cover the soil surface with very fine grit or sand. This is useful for preventing algae and moss proliferation on the soil surface.
Well, keep growing !