Germinating the seeds
Seed pre-treatment -- Scratch each seed a few times over a nail file or sandpaper to make it easier for water to enter. Then soak the seeds in a cup of water for 24 hours (not more than 48 hours).
Planting -- Start with small pots or cups that are about 3 inches tall (8 cm), with drainage holes. Use well-draining soil. I use a mix of 1 part coir fiber to 1 part perlite (use small- or medium-grade perlite, not coarse-grade). An alternate mix is 2 parts quality potting soil to 1 part perlite.
Fill each pot with soil and water it. Then put 1 seed in each pot, cover with 1/4 inch (6 mm) of soil, and water the top layer lightly. I get good germination at 65-77 degrees F (18-25°C). I've never tried sprouting them outside this temperature range. I recommend placing a minimum/maximum thermometer near the pots.
They should start sprouting within 2 to 4 weeks, but allow up to 8 weeks for any slow ones. Once they sprout, give bright, indirect light. Protect from strong sun exposure.
Fertilizing -- The first 6-8 weeks, feed every 7 days with a very dilute (1/8 strength) liquid fertilizer. Hydroponic fertilizer is ideal for this, because it is easily absorbed and contains all essential nutrients. I use General Hydroponics Flora fertilizer, using 1 teaspoon/gallon (5 mL per 4 liters). After 6-8 weeks, you may switch to a granular fertilizer that contains micronutrients, following the dosage on the package. Or continue feeding weekly with liquid fertilizer at 1/8 strength.
Temperature & humidity -- Carmichaelia grows well between 45 and 80 degrees F (7-27°C), with cool nights. Since the plant is so rare, i have no information on well it will do outside that temperature range. Feel free to experiment with rooted cuttings. Your plants can be grown indoors, provided that the air isn't too dry. Between 40 and 80% humidity works well. If the humidity drops too low in winter, consider using an ultrasonic humidifier, which are sold at home improvement stores and thrift shops.
Lighting -- It prefers mostly sunny conditions. In warmer climates, some protection from strong afternoon sun may be needed. Also keep the pot shaded in warmer climates, to keep the roots from overheating.
Watering -- Carmichaelia likes soil that is lightly moist throughout. Avoid letting the soil dry out completely, but also avoid keeping it soggy. If you're unsure if the soil down in the root zone has the proper moisture, you can use a moisture meter.
Transplanting -- When your plants are 4 inches (10 cm) tall, transplant to larger pots. Water the soil first, to keep the soil ball from breaking apart, which can damage the roots.
Once the plants get about 12 inches tall (30 cm), transplant them to a 2-5 gallon pots (8-18 liters). After 2-3 years, they might need 10 gallons (40 liters) or more.. although smaller pots might work if the trees are pruned back regularly. You may prune the plants to any size that is convenient.
Pests to watch for -- mealy bugs, scale (small brown disks - hard to see), spider mites, slugs & snails. Try using insecticidal soap before using stronger remedies, since some may harm the plant.
Enjoy your plants!
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