Here are some pictures of my decidedly low tech seeding set up. The exterior shot shows my lean-to greenhouse attached to the south side of my workshop. I built the greenhouse from hoops scrounged from my neighbours junk pile. I've been using it about 10 years or so, and it works well. It has no heating system of it's own but relies on the warmth of the sun and a bit from the woodstove that heats the barn on cold winter days. For many years the benches inside were built on water filled, black painted barrels which soaked up the sun's heat during the day and radiated it back into the air at night - this seemed to work well but the barrels rusted & the water leaked out and so I built new tables this winter made of wood.
Inside the greenhouse I've built a smaller greenhouse and inside of that is my germination table.
It's an insulated wooden tray with electric heating cables covered with a layer of sand. I seed into plastic plug trays which will be placed on the warm sand. It holds 9 trays. On really cold nights I set up a small electric heater at the open end to blow warm air over the trays. Not much to it - but it works well, and I started over 12,000 seedlings there last spring. Space is always at a premium so sometimes the plug trays are stacked 2-3 high. As soon as the seeds germinate they are moved out into another area of the greenhouse.
So tomorrow's day 1 of seeding. I'll be starting the first tomatoes, chives, garlic chives, catnip,
There may be snow outside - but spring is finally here!!