I have some different colored Datura seeds and am wondering if they need cold stratification to germinate. I was planning on starting them indoors in Feb. under lights. They could be moved outdoors in my part of the world in March.
They definitely do NOT want cold .. the best way to start datura seeds is to cut a sliver off of the seed coat with very sharp scissors or a knife. Just enough to break the coat. Then plant to the depth of seed in moist but not wet potting soil. They do not need light to germinate. Bottom heat will speed up germination considerably. The fresher the seeds are the sooner they germinate. Seeds that are a year or more can take longer. Some datura can take as long as 6 months to germinate so don't give up on them.
I use a heating pad to start my seeds with the soil temperature around 85 - 90 degrees. Once you have germination and the cotyledons (first leaves with pointy tips) are fully developed you'll want to drop the soil temperature to around 75 - 80 degrees. Once they start setting true leaves (rounder tips) you can wean them off the heat altogether and pot them up.
In the picture the ones on the right are just germinated seeds with cotyledons showing. The ones on the left have their first set of true leaves.
Do they over winter for you or is that just the native species here? I had no idea it took so long for germination. Thanks for the information. I have a couple seedlings that I have been overwintering and hopefully those will take off when I plant them this spring.
Since they bloom the first year from seed I treat them as annuals. Once the soil temperature warms up they should start growing very fast .. I feed mine once a week with any generic 1 tbs per gallon food like miracle grow. Once they start blooming you'll want to cut off all spent flowers and not let them produce seed pods since the vigor and quality of the plant will go down hill rapidly if it's trying to produce seeds .. Around the end of July I'll let 2 or 3 pods grow per plant for seeds next year .. datura produces tons of seed so 2 or 3 pods will be sufficient.
If you're not sure how far to cut down on a spent bloom, the picture will show you.