How long do new guinea impatiens take to germinate? I sowed them along with my ivy geraniums on Feb 10th on heating mats set to 78F. Most of the geraniums germinated within 4-5 days. Nine days after sowing them not a single impatien has germinated. Did I do something wrong? They are on heating mats under a large vented dome in a dark area of my basement. I mist the surface of the soil every 3 days when it appears to be drying up. This is my first year doing impatiens so this is a learning experience for me. I usually sow calibrachoas but decided to change things up this year.