Good luck in this creative and interesting work, Peyton!
My recommendations are very simple but can be useful if you start with hybrids for the first time.
1. To get interesting hybrids crotons with distinctive features should be cross-pollinated. It will also increase the chances to get something absolutely new as a result. Certainly you can predict what you can get as a result judging by leaves’ shape and colors of parenting plants. But there is always a chance to be surprised by “hidden” gene as the origin of many crotons is a mystery.
2. I apply pollen with a tiny soft brush to the center of female flowers.
3. Manage to get all ripen seeds. The more the better. More chances to get something new. In case of self-sowing… nature favors green seedlings as they are usually stronger than their colored siblings. To get all the seeds without any loss use light material to cover a bunch of maturing seeds (I use medical gauze bandage). So you don’t need to worry about seeds when they start catapulting for many meters.
4. I set seeds to the depth not more than 0.5 – 1cm (depends upon their size). It’s optimal for them to start growing. Some of them start to grow too bright (yellow) from the beginning – these ones need to be shaded for successful growth. Sometimes I remove yellow tops and they begin to grow green.
5. I’ve tested different potting mixes for seeds and come to the conclusion that they best do in the mixture of coconut coir and vermiculite. This mixture is sterile and I don’t have problems with rotten roots. Some young seedlings are rather vulnerable and you should keep good growing conditions (temperature and light).
6. When young seedlings become stronger I plant them in more nourishing soil.
7. Don’t hurry to get rid of hopelessly green plants. Many hybrids require very good light and start colored when get matured.
8. Keep documenting which crotons you use for pollination. In 4 years there is a chance to forget the origin of new croton sensation
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