I am starting Dahlia seeds indoors using a heat mat. about half of the seeds germinated in 4 days and have sprouted. Others in the flat have not started yet. My question is should I leave them on the heat mat?I understand once they sprout you should take them off of the heat mat, but I'm wondering about the other half, which have not yet sprouted.
Multnomah County Oregon seed germination
It's possible the other seeds will not germinate. I'm not familiar with the average germination of dahlia seeds (are you doing your own hybridization?) according to this site https://www.gardeningknowhow.com/ornamental/bulbs/dahlia/starting-dahlia-seeds.htm average germination is 7-12 days so I think it's worthwhile to leave the other half for another week or two.
Thanks Sara. This is my second year of starting annual flowers from seed, and finding out it's as much art as science, and alot of fun. My concern was overheating the roots of the sprouts. I think I'll take them off the heat in a day or so, and let the unsprouted seeds fend for themselves for another week. I'd rather lose them than the sprouts.