Two weeks is enough time to clearly announce that there is a winner in the seed start kits. While I still recommend Jiffy pots because they are so economical and easy to come by for starting seeds, this new Bio Dome seed starter kit from Park Seed clearly is outperforming the Jiffy pots in both size and percentage of sprouts. To be fair, the Jiffy pots were started one day behind the Biodome seeds. The Bio Dome has sprouted 84% of the seedlings, the Jiffy pots only 25% have sprouted. The size of the tomato seedlings in the Biodome is 2-3 times the size of the Jiffy pots. No, I'm not being paid to say this. I do find these results interesting.
I'm a convert. I think I will be ordering more Biodome plugs and seed starter kits.
To order a Biodome seed starter: Bio Dome seed starter
There are refills you can order as well, which are actually sponges, not dirt. And they stay more consistently moist which seems to make a difference.
The winner: Bio Dome seed starter, 84% success rate in my test
The Jiffy Seed Starter kit, only 25% success rate in my test but still a cheap option.