Fertilizing seedling is very important to development and growth. Fertilization should begin soon after your seedlings grow their first “true” leaves. The first leaves that emerge from the seed are called the cotyledons. They’re rounded with smooth margins. The second set of leaves to develop is the “true” leaves. They look very similar to the foliage of the mature plumeria. When the first 2 sets of “true” leaves have fully emerged, it’s time to start providing your seedlings with nutrients and move your seedlings to the next stage in their care.
When the “true” leaves arrive, your seedling will have developed roots and need nutrients and sun to help convert the nutrients into plant food. There are lots of different potting mixes you can use, but I suggest ones that contain 1/3 pine bark, 1/3 peat, 1/3 perlite with Mycorrhizae. Potting soils with nitrogen will cause your seedlings to grow lanky. Lack of sunshine will also cause your seedlings to grow lanky
When you transplant your seedling into pots, it’s time to begin fertilizing with a balanced granular fertilizer containing micro-nutrients. I suggest slow-release Excalibur 11-11-14 or similar.
Suppose your seedlings get stressed from heat, too much rain, or insects. It’s beneficial to use a quick-release granular fertilizer or a liquid fertilizer. I suggest Excalibur BOOST 10-12-14 or Bioblast 7-7-7. You can use Excalibur BOOST every two months and Bioblast every two weeks. Choose a product formulated for use on seedlings.
If you haven’t started your seedlings in full sun, you will need to introduce them gradually. Begin by placing them in a shady spot outdoors for just a few hours. Slowly leave them outside for more extended periods and expose them to more sunlight until they are in full sun for at least 6 hours per day. This hardening off process is significant to young seedlings and helps them gradually adjust to brighter light levels, wind, and fluctuating outdoor temperatures.
NOTE: If you live in a region with extremely hot temperatures you may need to use shade cloth or less exposure to the hot sun.