It’s great to get an early jump on spring planting but you also need to be careful, particularly in an April like the present one, when there’s been an extended chill that has kept up for almost the entire month. You don’t want to damage your seedlings by leaving them out in a frost overnight.
It’s easy to get annoyed hauling your trays of seedlings in and out, from the living room floor to the patio; but there actually may be some benefit in leaving the seedlings outside overnight, as long as there isn’t an actual frost. According to Daphne S., co-manager of the ECI garden, your tender lettuce seedlings will benefit from some cold conditioning by leaving them on the patio overnight. The agricultural term for it is “hardening” them up.
Here's a picture of the fenced in yard where ECI’s juvenile lettuce leave do their “hard” time. The area is fenced in so critters can’t get to the tender leaves, but we leave the seedlings in their trays for now, in case there’s a freezing night still to come.
