There is a lot to be done before you start the seeds for next years garden.
Read seed catalogs, choose too many seeds
Dig out saved and older seeds, figure out which ones are still good
Buy potting soil or use your own compost
Beg, borrow and otherwise gather enough 2" to 4" pots and waterproof trays
Cut plant tags out of yogurt cups
Make chamomile tea for watering seeds
Get out the old lamp and put it under the card table
Hang and plug in grow lights, if you don't have a window nearby
When is the best time to plant? This can be a complicated judgment call with erratic weather patterns and late Springs, but unless you are psychic, you have to just shoot for a goal time and roll with the changes.
A nice thing about starting your own plants is that you will have plenty to make mistakes with. No matter what happens to my plants in the garden, birds, bugs or weather, I have replacements on my windowsill.
And if I don't use them all, I have several friends who are happy to take them!