"White Tree Sunflower"
Germinating the seeds
When to plant -- Plant your seeds when you receive them for best results.
Getting started -- Soak your seeds in a cup of water for 24 hours (not more than 36 hours).
Use any small containers that have drainage holes. Use a well-draining soil mix, such as 2 parts potting soil to 1 part perlite, or equal parts of perlite and coir fiber or peat. Fill each container almost to the top. Place 1 or 2 seeds on top, and sprinkle a thin layer of soil on top, about 1/4 inch (6 mm). Don't compress the soil. Add water until the soil is evenly moist (but not fully saturated).
Place the pots in moderate temperatures (about 65-77 degrees F / 18-25°C). Avoid letting them get warmer than 80°F (27°C). I recommend placing a minimum/maximum thermometer near the pots.
Keep them in a bright spot, but not in direct sun. Ensure that the soil surface never dries out, possibly by enclosing the pots in a humidity dome or large bag. Leave the dome or bag open a crack to let some fresh air in. You may need to drip a few drops of water on them each day.
The seeds can begin sprouting within 2-3 weeks, but may take up to 8 weeks. Once they sprout, give them some extra air circulation to avoid getting stem rot.
Water the soil whenever the surface looks dry, but don't keep it always soggy either. If you have more than one seedling in each container, snip off the weaker one(s) when they are 4-6 weeks old - or very carefully remove them.
I recommend growing them indoors until they are at least 3 months old. For lighting, you may use a bright fluorescent or LED bulb kept about 4 inches (10 cm) from the plants. Avoid incandescent (screw-in) bulbs, even if they're called "plant bulbs". You can also put them in filtered sunlight. Protect them from strong, direct sun.
If the indoor humidity drops below about 40% humidity, consider using a room humidifier.
Watering - Aim to keep the soil evenly moist (but not soggy) most of the time. They use a lot of water, so do not let the soil dry out. A moisture meter probe works well for monitoring moisture levels down in the root zone.
Fertilizing -- Feed weekly 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. After 6 weeks, you may switch to a granular fertilizer, following the dosage on the package. Or continue feeding weekly with dilute liquid fertilizer.
It's normal for an older leaf to occasionally turn yellow and drop, but if it seems excessive, the soil may be too dry in the root zone. If you are certain that's not the case, the plant may need more fertilizer (nitrogen).
Repotting - Repot your plants to larger containers whenever the plant becomes root-bound. Water the soil before repotting, to keep the soil ball from breaking apart, which can damage the roots. By the second year, the plant will need a very large container - at least 10 gallons (38 liters), and preferably larger. If you must keep it in a smaller container, you may need to prune it to a smaller size, but do this before October if you want it to flower the following year.
Growing outdoors - The plant prefers filtered sunlight, with protection from strong afternoon sun. Morning sun + afternoon shade is fine, as is tree-filtered sunlight all day. If the leaves wilt, try giving it more shade. Keep in mind they may still wilt in warm temperatures.
It enjoys moderate temperatures and cool nights, and is untested in warm climates. The ideal would be between 50 and 80° F during the day (10-27°C), and 40-70° at night (4-22°C). In warmer environments, give the plants afternoon shade, and keep the pots shaded to avoid overheating the roots, or at least use a terracotta pot, not black plastic. Mature plants can probably can take a few degrees of frost, but i recommend protecting it from freezing temperatures, especially the first year.
Pests to watch for - whitefly, aphids, scale (little lumps on the stems or leaves), mealybugs, and possibly spider mites (tiny "dots" under the leaves).
If you have any questions, feel free to email me.
Have fun growing them!
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