Hi Claudia,

It is best to start impatiens seeds indoors 2 and 1/2 months before your last frost for outdoor plants. Start them anytime if you use them as houseplants. Use a sterile starting mix and clean containers. Seeds (don't cover them) need light, moisture, and 70-degree temperatures to germinate. Mist planted seeds or water from the bottom - don't overwater. Be patient it takes two to three weeks for the seeds to sprout. Impatiens are subject to damping-off disease, so provide good air circulation. 

Other references:

Starting seeds indoors - the University of Minnesota at this link: https://extension.umn.edu/planting-and-growing-guides/starting-seeds-indoors

Sowing Annual Seeds - Penn State University at this link: https://extension.psu.edu/sowing-annual-seeds

Starting Impatiens from Seeds - Iowa State University by Richard Jauron, Department of Horticulture at this link: https://hortnews.extension.iastate.edu/1996/2-9-1996/impa.html

IMPATIENS - Clemson University Extension at this link: https://hgic.clemson.edu/factsheet/impatiens/

IMPATIENS - the University of Vermont Extension at this link: https://pss.uvm.edu/ppp/articles/impatiens.html

Hope this helps

Hi Claudia,

Here is some updated information:

The days to flower should be indicated on the back of the seed packet. Sometimes it doesn’t say this but it will say “sow your seeds X number of weeks before spring transplanting. That gives you some idea

Another colleague and I searched on the Internet for “ impatiens seeds days to bloom” and some non-research-based sources said 10 weeks before impatiens walleriana seedlings bloom. Under ideal conditions in a production greenhouse, they had flower buds in seven weeks. Here is the production greenhouse article on that- https://archive.lib.msu.edu/DMC/Ag.%20Ext.%202007-Chelsie/PDF/e1580-1989-rev1.pdf

So 7 to 10 weeks seems to be the range depending upon growing conditions such as light, moisture, temperature.

Keep in mind, this was all for Impatiens walleriana, the common bedding plant. If you growing New Guinea impatiens that would be different. Here is the article (I previously sent) with essentially the same information for residential gardeners-https://hgic.clemson.edu/factsheet/impatiens/