It can be hard to propagate Impatiens from seed, but it can be done. To do so, you’ll need consistently warm soil and ample light for germination.
If you can keep your soil temperature at 75° degrees Fahrenheit temperature, you should do well. Failure to do so will cause fungus problems.
If you can set up the right conditions, your Impatiens seed should sprout within a week. In some cases, a little more time is needed.
Related: Growing Impatiens in Pots
12 Steps To Sow Impatiens Seed Successfully
1. Set up a tray or seed flats of well-aerated, sterilized soil mix.
2. Smooth the soil mix to level it and tamp it lightly to make it firm.
3. Use hot water of approximately 100° degrees Fahrenheit or higher and moisten the soil thoroughly. Wait about an hour and water again with hot water.
4. Allow the soil to cool enough that you can touch it comfortably. However, it should still be reasonably warm.
5. Sow your Impatiens seeds lightly over the surface of the soil. About 4 – 6 seeds per square inch are good.
6. Press the seeds into the mixture lightly, but do not cover the seeds. Remember that they need light for germination.
7. Use plastic wrap to cover your germination tray lightly.
8. Put the tray on a bottom heat source to keep the soil at the right temperature.
Remember that you want to keep your soil at a consistent temperature of 75° to 78° degrees Fahrenheit. Never allow it to become hotter than 85° degrees Fahrenheit.
Check frequently because you will be covering the soil with plastic to keep the humidity in, and it will also keep the heat in. It’s easy for the soil to become too hot.
9. Place the tray in an area where it will receive indirect, bright light. They can also be stated under fluorescent lights.
10. Mist the soil surface daily and allow air to circulate under the plastic for a little while each day. Keep the soil slightly moist, never soggy.
11. After the seeds germinate and begin to grow, you should keep temperatures at a consistent 65° to 70° degrees Fahrenheit. Walleriana seeds will germinate within two weeks. However, it can take as long as a month for New Guinea seeds to germinate.
When Should You Start Impatiens Seeds Indoors?
Different varieties require different amounts of time. For the New Guinea cultivar, you should start your seeds a good three months before you’re ready to plant your seedlings outdoors. Walleriana can be ready to plant outdoors in 2-1/2 months after the danger of frost has passed.