Hi Ken,
Even though we have never used Jiffy 7s we are using soil blocks this year so I will draw on that experience to answer your questions since they are somewhat similar. We have all ready started out tomatoes and some other things.For tomato seeds I usually use tweezers to pick up the sprouted seeds being careful not to break the sprout. If seeds are larger you can use fingers but tomato seeds are too small. I keep tweezers on my potting table along with some other small size tools.
John said he has found that some of the sprouted seeds just lie on top of the blocks and grow funny so he prefers to sprinkle some fine soil over the seeds. Sprouts from seeds can just be laid on top, don’t look for up or down sides. You may want to experiment with sewing directly to the Jiffy 7s instead of pre-sprouting. See which method you prefer. John keeps the soil very moist until sprouting has occurred then allows the soil to dry out some; slightly moist is a good goal. Since your seeds are sprouted you need to allow the Jiffy 7s dry out some although at first very wet is O.K. As the plants get larger they need to have drier soil occasionally.
To prevent damping off one of the first steps is to have sterile starter media, which the Jiffy 7s are. You can also add ‘Milled Sphagnum Moss’; it must be ‘Milled’. It has antibacterial properties, which fight the disease. A fan blowing lightly on your plants also fights the disease.
Happy Gardening,
Diane