April Johnson, landscape and greenhouse coordinator at the
Rodale Institute near Kutztown, Pennsylvania, grows literally
thousands of organic vegetable, flower, and herb transplants
every year. Many of her seedlings end up in the Institute’s
production and display gardens; others are sold to local
gardeners at two spring fundraisers. After many years of
experimenting with recipes for indoor seed-starting mixes,
Johnson has settled on this general formula. To keep the dust
down, lightly moisten the ingredients before blending them
thoroughly in a dishpan or wheelbarrow. This mix strikes a
balance between moisture retention and drainage, both of which
are necessary for seedlings. “Regulating the moisture is key,”
Johnson says. “It’s easy for the soil to stay too wet, and that
can lead to damping-off.” Damping-off is a fungal disease that
causes newly germinated seedlings to topple over and die. Some
flower seedlings—Johnson mentions pansies, snapdragons, ‘Gem’
marigolds, and lisianthus—tend to be more sensitive