This section is from the book "Tree Planting For Timber And Fuel", by C. B. Mcnaughton.
The propagation of tree seeds is very similar to that of ordinary garden seeds and can be easily conducted by most gardeners. The main factor in successful propagation is the proper condition of the germinating bed—the soil should be light and sandy, and moderately fresh and porous. Heavy soils should be avoided as well as fine compact ones which are in the habit of caking and thus interfering with germination. The bed should be kept at as even a temperature as possible and at about the same degree of moisture.
The proper covering of the seed is another important matter. Seed should never be sown too deep, twice their own depth is a fairly safe rule. With some of the very fine eucalypt seeds sowing on the surface and pressing firmly and evenly with a small board or roller is quite sufficient, but in these cases it is advisable to cover up with two or three folds of coarse open sacking such as is known as " hessian" and water through the material. Some very successful nurserymen cover all their sowings with a layer of one to two inches of chaff and water through this. The covering allows the water to percolate slowly through to the soil, holds the moisture well and prevents caking or packing or the washing away of the seed. Of course at the first sign of germination the coverings, either chaff or the sacking, must be removed.
At Oudtshoorn I would recommend always the use of coverings and sowing in shallow boxes or pans—half paraffin tins cut longitudinally, are found very suitable. With boxes the sowings can be easily handled and this is important where night frosts are to be feared. It is most important that these boxes should be well drained as any moisture is likely to cause "damping off"—a fungoid disease which it is difficult to check and is very destructive. As the seedlings come up, a certain amount of shading will be necessary. Screens made by stretching hessian on convenient frames will probably be found to be most suitable. They should be placed about 18 inches above the seedlings to protect them from the direct rays of the sun, a protection which will be necessary until the secondary leaves are formed when the young plants can be gradually hardened off prior to transplanting. After this operation the shading should be repeated for the first few days until the young transplants have "settled in." When to transplant will naturally depend on the species but generally the best time is as soon as the plants can be handled, which is often as the secondary leaves are nearly formed. Of course certain species, such as the Chestnut, do not transplant at all easily and these are best raised in situ. It is best to transplant into boxes similar to those used as seed pans— half paraffin tins—each of which will contain from 20 to 30 transplants. The soil in these boxes should be something similar in quality to that into which it is proposed to plant permanently. It is a common mistake to transplant into a rich forcing soil so as to show vigorous looking transplants which generally suffer when they are put out permanently under poorer conditions. Of course it is not easy to estimate exactly future conditions, but it is generally safe to have the soil in the transplant boxes of fair medium quality only, but well worked and sufficiently light to permit of the young plants forming good compact root systems.
In Oudtshoorn early Spring or late Winter planting is possible, though August—September seems the best time. This must be remembered when raising the transplant as it is advisable to plant out as early as possible with most species as the young plants should not be left in the nursery too long.