Soaking seeds
For seed to germinate, we need adequate water, air, and warm temperature. Dry seed when sown directly germinates slowly because it takes time for the seed to absorb the moisture needed to transform the starch, protein, and fats into simple food for the embryo. On the other hand, seed germinated before sowing grows more uniformly, faster, and are less affected by diseases, insects, and birds (Macalinga and Abordo 1970). Pre-germination consists of soaking seeds in water and incubating them.
The first requirement for seed germination is uptake of ample moisture. Soak seeds for at least 24 hours so that they absorb water. The table shows the number of days required to soak seeds at temperatures below 27 °C to initiate gemi-nation (Mallick 1982); this is a common practice in the Himalayas, northern India, and Pakistan.
| Average water temperature (oC) | Days of soaking (no.) |
| 10 | 10 |
| 15 | 6 |
| 22 | 3 |
| 25 | 2 |
| 27 | 1 |
Incubating the seeds
Incubation keeps the seed warm and hastens the growth of the embryo, resulting in uniform germination. After soaking, water is removed and seeds are washed, placed on a flat surface, and covered with a burlap sack or any material to build up the heat. Temperature between 20° C and 30° C is found to be ideal for rapid growth occurring within 1-2 days. A lower temperature decreases activities inside the seed; while a warmer temperature increases them, thereby, increasing the rate of growth.
Incubation is done by spreading the seeds on a flat surface 10-15 cm deep and keeping them well covered with moist burlap or canvas material. For dapog seedbed, the seeds are incubated for 36-48 hours, allowing the roots to grow to 3-5 mm long before sowing in the seedbed. For wetbed seedbed, 24-36 hour incubation is sufficient. Aerial seeding makes use of seeds that are soaked for 24 hours when the radicles (roots) would just start to break out. It would be hard for the longer radicles to pass through the small opening of the calibrated hopper door of the aircraft (author’s experience).