Step 2: Plant the seeds. The most critical step in growing angel trumpet from seed is to plant the seeds correctly. Angel trumpet seeds require light to germinate. If you bury them too deeply, your germination rates will be greatly reduced. After filling the pots with potting soil, simply press the pre-soaked angel trumpet seeds firmly against the soil, but don’t cover them. Water the pots immediately after planting and then cover them with a piece of clear plastic to keep the humidity high around the seeds.
Step 3: Give them heat. Angel trumpets are tropical plants, native to South and Central America. Warm soil temperatures improve germination rates and speed. I use a seedling heat mat to warm the soil 10-20 degrees above room temperature, just enough heat to make growing angel trumpet from seed a successful endeavor. Leave the heat mat under the seed pots until the seedlings germinate, then remove it. It will take 3 to 4 weeks for angel trumpet seeds to germinate, so don’t lose patience!
Step 4: Turn on the lights. Because both types of angel trumpet seeds need light to germinate, put the pots under grow lights or fluorescent shop lights immediately after sowing. Position the lights so they’re just 2-3 inches above the plant tops, raising them as the plants grow. Leave the lights on for 18-20 hours per day (use a timer like this one, if you want to automate the lights). It is possible to grow angel trumpet seeds in a sunny windowsill, but the seedlings are often leggy and pale. I highly recommend using lights, if at all possible.
Step 5: Water as necessary. One of the most important aspects of growing angel trumpets from seed is to make sure the seeds don’t dry out prior to germination. Because they aren’t buried in the potting soil, newly planted Brugmansia and Datura seeds can become desiccated before they even germinate. Make sure the pots stay well-watered, but don’t allow them to become water-logged either or the seeds could rot. Once the seeds have sprouted, remove the piece of plastic and the heat mat, and continue to water as necessary.
Step 6: Fertilize every two weeks. As your angel trumpet seedlings grow, fertilize them every other week with a half-strength solution of a liquid organic fertilizer. Don’t over-fertilize when growing angel trumpet from seed or you could burn the tips of the plant’s leaves.
Step 7: Harden plants off before moving them outdoors. Both types of angel trumpets are extremely sensitive to frost. Do not move them outdoors until the danger of frost as passed. The biggest disappointment when growing angel trumpets from seed is moving them outdoors too quickly and watching them wither and die (ask me, I know; it’s a very sad thing to experience!). To harden off angel trumpet plants, as soon as the danger of frost is gone, move the pots outdoors for a few hours every day and put them in a shady spot. Over the course of 10-14 days, gradually increase the amount of sunlight they receive and the amount of time they spend outdoors until they’re out in full exposure both day and night. Only then are your angel trumpet plants ready to stay outdoors for the season.
If you live in an area with snails and slugs I recommend putting snail bait around the base of your plants. Do not put to close to a house or a fence because snails and slugs will crawl onto this to get to your plant and eat them all the way down.