Rhododendrons and azaleas are easily grown from seed. Unless the parent plants are species from isolated areas, the resulting seedlings will exhibit much variability. Unless you are interested in hybridizing and selecting new cultivars, use of seeds as a means of propagation should thus be limited to species plants. Even then some physical differences will be evident.
- Obtain clean seeds.
- Prepare a sterile container at least three inches deep, with bottom drainage; size depending on how many seeds you wish to plant.
- Fill the container to within ½ inch of the top with a mixture of 40% perlite and 60% fine sphagnum peat moss. This mixture should be moist...but not wet.
- Level and firm the surface of the mix.
- To control fungal disease, spray the soil surface with fungicide Captan. Read and follow product instructions.
- Sprinkle seeds thinly on the surface...do not water again.
- Put plastic or glass over the container to make it moisture tight.
- Place in a warm dimly lit area until seeds germinate.
- Put under fluorescent light for 18 hours a day at 70-75°F.
- Anytime after true leaves have formed, harden the seedlings off by gradually opening the cover over the period of at least one week. Water carefully as needed to keep moist. Watering through drainage holes in the bottom is safest.
- Transplant when ½ to 1 inch tall to flats using 50% sphagnum peat and 50% perlite. Lift under the roots and handle by a leaf. Plant at same depth. Water to settle in.
- Water to keep moist, but not wet. Fertilize with azalea food or other acid fertilizer once a month using ½ half strength. Always water at least once between fertilizer applications. To slow growth and harden off, stop fertilizing and water less frequently.
- Transplant when seedlings become crowded.
Keep the growing area clean to prevent damping off, water properly, and...success is almost assured!