We have had success with our grow lights and starting most of our flowers from seed and expect to continue to allow this to take over our laundry room for many future winters. I'd love to have a basement or larger room for seed-starting, but our old house is full of a lot of smallish rooms and has no real basement (we have what most would call a cellar and it has our furnace in it, so it is far too warm for seed-starting or even dahlia-storing).
Seed packets ready to be planted
Trays of my precious Vermont Compost Fort Vee mix being seeded on the kitchen counter.
We now have two triple tier grow lights from gardenerssupply.com that I've been given as Christmas and birthday present over a couple of years. They are on wheels which is helpful because it is like a maze in our small laundry room and getting into the cabinets is a tight squeeze. This set-up allows 5 small trays (Garland small trays which are usually available from the Greenhouse Megastore) on each of the tiers--that's 30 trays that can be growing plants at any one time. We seed one variety per tray and then prick out the seedlings into larger trays. Once these trays are done they can usually be moved out to the newly heated greenhouse or the high tunnel. On cold nights they might need to come back in the house because I do not entirely trust the heater in the greenhouse yet, even though it seems to be doing an excellent job keeping plants alive. Seed starting is time consuming and a demanding time of year and it begins in January and does not end until sometime in April or May when the outside work has really ramped up and we are in full flower growing mode. It really makes winter go by faster. ;)
Scabiosa and stock seedlings just up in January.
Our seedling carts in the laundry room with the mess of cords running into a timer that keep them lighted for extra long days in the winter. There are also heat mats under several trays. The piece of paper taped to the cabinet is my cheat sheet with seed starting instructions for most of the flowers I'm growing. It can be hard to remember the depth of each seed and whether they need light or no light for germination and which need heat or no heat. If I have to take the time to look it up for each seed it can take forever (many commercial seeds come without instructions).
My favorite sources of seed that are available to the public are Johnny's Selected Seeds, Harris Seed, Renee's Garden, Eden Brothers and many more. I particularly like Eden Brothers, Johnny's and Harris because they offer large quantities. When you want to start a seed like Shirley poppy, larkspur, bachelor's buttons, nigella, California poppy or anything that self-sows easily I find that the best way to get it started it to mimic self-sowing by scattering a large number of seed (I've scattered 1/2 pound of poppy seed over a fairly large area). Some of these plants do not like to be transplanted and simply won't tolerate it--for instance I find Shirley poppies to be weak if grown from transplants. So I follow very old advice to sow the seed on the last snow of winter. When is that? Well any snow in February or March will do in my zone 6B garden. Run out there in the early morning before the sun hits that snow and throw the seeds on the snow over bare ground where you want them to grow. I've had great success with this method over the years and used it with all of the seed mentioned above. In a year with no snow a cold, wet morning will do.
This year has already been a tough year for growers. Seed suppliers are running behind on fulfilling commercial orders for various reasons relating to the pandemic and this will likely also affect home growers. Don't be surprised if the company you've relied on for years is out of stock of your favorite seed and unable to get it this year. We who have access to wholesale suppliers have been scrambling all winter and we feel your pain. Surely, next year will be better. :)