Germinating the seeds
When to plant -- Plant your seeds when you receive them for best results.
Getting started -- Soak the seeds in a cup of water for 4 to 6 hours (not more than 12 hours).
Soil -- This Cestrum likes soil that's high in organic matter/humus but that also drains well. A typical mix is 2 parts potting soil to 2 part perlite or coarse horticultural sand. An alternate mix is 2 parts coir fiber or peat moss to 3 parts perlite, with some slow-release fertilizer mixed in.
Pot size - You may use small pots or cups about 1.5 to 3 inches (4-8 cm) wide and 2.5 to 4 inches tall (6-10 cm). The pots should have drainage holes.
Fill the pots with the soil mix and water it until it is evenly moist (but not soggy). Place 1 seed on top in each pot, and sprinkle about 1/8 inch (3 mm) of soil over it. Carefully moisten the top soil layer.
Until the seeds sprout, keep the surface soil from drying out. If you place the pots in a plastic container or bag to maintain moisture, leave it open a crack to allow fresh air to enter.
They sprout well between 65 to 77° F (18-25°C). I have no information about how they will germinate outside that temperature range. Keep them in a bright spot out of direct sun. They should begin sprouting within 4 weeks, but allow up to 12 weeks for any slow ones, especially at cooler temperatures.
Lighting -- Once your seeds sprout, move them to a bright spot, with protection from afternoon sun. You may use a fluorescent or LED light kept a few inches (10 cm) away while your plants are young.
Watering: Once the seedlings are 3 weeks old, you may allow the surface soil to dry out, but aim to keep the rest of the soil evenly moist most of the time. Never let it dry out completely, but also don't keep it perpetually soggy. .
Feeding -- This species has average fertilizer requirements. Feed about every 2 months with a general-purpose fertilizer.
It's normal for a few of the older leaves to occasionally turn yellow and drop, but if it seems excessive, the soil may be too dry down in the root zone. Or the plant may need more nitrogen fertilizer.
Climate -- This species comes from mountain forests, where the climate is mild all year, and nights are cooler. I have no information on how much heat it can take, so consider it experimental in areas that regularly get above 85 degrees F (29°C) especially if nights are warm. I don't know its frost tolerance. It might only be hardy to 25-30° F (-3°C). Protect plants from frost the first year.
Adult plants flower the strongest in mostly-sunny conditions, but younger plants should be acclimated to afternoon sun slowly. Over about 40% humidity is best.
Repotting -- Once your seedlings are at least 3 inches tall (7 cm), you may repot them to larger containers about 1 quart (1 liter) in size. Repot gently and avoid letting the soil ball break apart. It's best to water the soil before repotting to keep the soil together. For the first week after repotting, shade from sun and give no fertilizer.
If you have any questions or problems, please contact me.
Have fun growing them!
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