What Nursery Practices are Done at the BNCRDC?
Seedbed / Seed Box Preparation
The porosity of sowing media should be lower at least by half than that of potting media. This is to ensure good drainage and prevent fungal build up. Pure sphagnum moss and coir dust are good examples of sowing media.
If you prefer a seedbed to a seed box, prefer the media first. After the media has been prepared, elevate the bed at least 15-20 cm (6-8 in) to prevent flooding that may cause contamination.
It is more convenient to use seed boxes because the media can be easily prepared. Furthermore, seed boxes could be easily elevated or carried to the shade when necessary.
Selection / Collection of Planting Materials
Rootstock selection. The rootstock varieties range from slow to fast-growing ones. The Center prefers the Carizo rootstock because any citrus type could be budded into it. Also, its rate of growth is intermediate. Fast-growing citrus types like lemons, limes, etc., are not recommended as budding rootstocks because it may result in incompatibility between the scion and the rootstock later.
Seed Collection. If you collect your own seeds, get them from fully mature fruits that have been harvested from middle to upper portion of the tree canopy. This practice reduce the possibility of collecting fungus-infected or contaminated fruits. Fruits in the lower canopy usually carry pathogens. For this reason, do not use seeds from fruits that have fallen to the ground.
Extract the seeds and soak them for 10 minutes in hot water at a temperature of 52 degrees Celsius. Afterwards, drain the water and coat the seeds with an appropriate fungicide. Air-dry the treated seeds in a cool, shaded place.
You can sow anytime as long as the seedbed or seed boxes are protected from the rain. You can transplant either when the seedlings have 2-3 leaves or when the seedlings range from 3 to 6 in tall.
If you intend to transplant at the two to three leaf stage, broadcast the seeds closely on the surface of the medium. However, if you intend to transplant when the seedlings are 3-6 in high, equally space the seeds an inch from each other. First, make parallel lines an inch apart on the medium, and then plant the seeds an inch apart on these lines.
Cover the seeds uniformly to a depth of 2-3 cm using the same medium. Ensure that the cover is not too thin or too thick. If the cover is too thin, the seeds will be exposed when they are watered. On the other hand, a very thick cover may result in goose-necked roots and also delay germination. After sowing, water evenly using soft shower droplets.
To hasten germination, ensure that the medium retains enough moisture at all times. Do not allow the medium to dry longer than 2 days in the hot season. On the other hand, unnecessary watering should be avoided.
Characteristically, citrus seeds germinate unevenly resulting in poor seedling uniformity. If the seedbed is crowded, the larger seedlings will overshadow the smaller ones; thus, compounding the lack of uniformity. To prevent this, select the bigger seedlings early and transplant them right away.