When you seed packages say "as soon as the ground can be worked" it means it. If you aren't expecting a lot of rain or unusually cold temps, and you squeeze a fist full of soil together and have it crumble apart, the soil is ready. Peas, tatsoi, bok choi, spinach and other seeds like cool ground. I plant my peas when the forsythia bloom. Some of the cool weather transplants are broccoli, cabbage and kale.

I try to get my warm plants in the ground when they're six weeks old. Their roots aren't so big and compact that they're disturbed much. It reduces something called transplant shock. I try to get my cool plants in the ground when they're around five weeks old. If you have a forecast for unexpected frost or even snow you can cover the seedlings with a sheet to give them a little protection.

Start these seeds indoors -
Tomatoes, cucumbers: 4-5 weeks before last frost.
Melon: 3-4 weeks before last frost.
Eggplant: 10 weeks before last frost.
Peppers: 8 weeks before last frost.