Growing Plumeria from seed is exciting. I grew my first plumeria's seed in the beginning of 2009. I purchased from ebay. At that time, I didn't have experiences to buy seed from International buyer, until I got notice from US Custom that they declined my package from Thailand due to missing Phytosanitary Certificate. However, I received my first package from Thailand, I was lucky :). Since I got notice from US Custom, I stop purchasing seed from oversea, unless they provide Phytosanitary Certificate. I started search local buyers in US. So, if you would like to purchase seed from abroad, check with your local custom whether you will need Phytosanitary Certificate or not, an additional cost may be applied.
Many articles about how to grow Plumeria from seed in the internet. I have tried different ways, some of them works but some are not. The important thing to grow plumeria are the viability and the freshest of the seed. Try to purchase a fresh seed by asking the buyer how old the seed. However, other components are important to encourage the germination. Here are some tips that easiest and work for me (based on my experiences).
How to grow Plumeria from seed
1. Soak seeds in 1/2 liter or 2 cups of water, add 1-2 drops Superthrive. If you don't have Superthrive, it is not the end of the world. However, Superthrive helps germination. Soak the seeds while prepare media and container. It is about 15-20 minutes.
2. Preparing media, provide well drained soil. I used to make my own mix media. I use cactus mix, perlite and vermiculite. Vermiculite is able to retain water, as well as open out the texture of planting mixture to improve drainage. However, fresh and viable seed will germinate in any media as long as contain nothing harmful. One day, when I was lazy to make mix soil, I used sponge soil. It worked, but I prefer to use mix soil because I used to keep the seedling at least 5-6 months, then transplant them to bigger pot.
3. Fill container with soil mix you made. Any containers are fine, but I like using clear container so I can see the root growing. I use spinach container or salad container. Make some holes in the bottom to let the water out.
3. Rinse the soaked seeds. Do not throw the water, add more water if necessary and water the soil gently. Make sure all soil completely wet but do not over water.
4. Sow the seed pointed down with wing stick up about 1/2-3/4 of the seed into the soil, firm the soil around the seed gently or spray very little water around the seed.( See above picture)
5. Place them in sunny and warm place, morning sun exposure is good. Keep the soil moist but not wet. Do not cover. They will germinate between 3 - 21 days.
6. When the seeds sprout out, gently remove the husks (the seed skin) off. Some time they stuck on the cotyledons, do not force to pull them out, spray with water around the husk first, and remove carefully. Be sure to always remove the husk, otherwise they will die because they will rot. Once the husks removed, the new leaves will emerge from above the the cotyledons.
My baby plumeria seedling, they are about 1.5 months.