In January 2015, I wrote a blog about starting seeds and growing transplants under fluorescent lights. This blog talked about replacing fluorescent tubes after they started to loose the quantity (lumens) of light they produced. Below is a picture of a lettuce box I use as an exhibit for my container gardening talks.
I start most of my seeds under fluorescent lights and transplant them into the garden at the time recommended by HGIC's HG-16 Planting Dates for Vegetables Crops in MD or GE007 Vegetable Planting Calendar for Central MD. Based on my planting date for Clarksville MD, I constructed a spreadsheet that calculates seed starting dates for all of my vegetables. While my timing ( weeks prior to plant out date) in my spreadsheet tends to be a little shorter than the number of weeks found on the backs of some seed packets and on the GIEI webpage, I find that I get younger and stockier plants by starting plants later and moving them into my cold frame the week prior to the plant out date.
This spreadsheet can be found of the Howard County MG GIEI webpage. The link to the spreadsheet is on the top right of the page under Quick and Useful Links.
So onions are started this week and the brassicas and lettuces two weeks later. The days to germinate and my number of weeks to start the seed prior to the outdoor planting date are taken from the back of the seed packets, the Johnny's Seed catalog or my experience.
I even start most of my squash and cukes indoors in 4 inch pots, 4 seeds to a pot. I cut off the two weakest seedlings and when I plant them out, cover then with row cover until they start to bloom. Using this method, I get excellent results and with the help of Surround (kaolin clay), I manage to keep the squash bugs and cucumber beetles to acceptable levels. It also allows me to start transplants during late spring to replace spring crops pulled in early summer.
The GIEI website has lots of useful info on seed starting. Many people will start their seedlings in a communal pot and transplant them to individual pots after they have their true leaves. Because I have a number of lights, I grow all of my seedlings in individual cells of cell pack. This saves me from transplanting them to larger containers. My system works well for me and over the years has saved me lots of money versus buying transplants from a nursery. It also allows me to insure that the variety of vegetable transplants are available when I need them.