The seeds of fertilizer trees are covered with a natural coat which protects them but which also slows down the germination process.
Some seeds require a scarification, which breaks this protective envelope.
The seeds of moringa or gliricidia require only a soaking of 24h.
Several techniques are used.
With APAF, during our training in Southern Africa, Pascal Humbert presented the following techniques:
1- The seed membrane is weakened by rubbing against a rough wall (eg cement floor).
2- The seeds are immersed for 10 minutes in hot water (60-70 ° C approximately). Then pour fresh water and soak for 24 hours.
In case of large quantities of seeds, option 2 is faster.
The visuals below show these different stages. The seeds, whose envelope has been weakened, swell rapidly and germination can start quickly after transplanting in soil.