If you don't yet have a high tunnel, you may be starting seeds indoors - in your farmhouse. Don't worry! You can do this. It's going to take a bit of creativity, but you can use your basement, garage, barn or even living room to get your seeds started.
Basic Requirements for Starting Seeds
To start seeds indoors, there are a few requirements. First, you'll need to understand the basics of how to start seeds. Seeds require a warm, moist environment to germinate. Once they have sprouted, they require light. Typically this means finding a space that can be maintained at 55 to 75 degrees F all day and night. You can use seedling heat mats under those plants that need a little extra warmth, like tomatoes and peppers, if your space is on the cooler end. You could consider a small portable heater to warm the space for the evening hours (just make sure it's safe to leave overnight without risk of fire).
The other thing you'll need is light. Usually, gardeners use fluorescent lights, but you can also use high-intensity lights like high pressure sodium or metal-halide bulbs. LED lights are another newer technology for indoor gardening. They don't run as hot as the other high-intensity lights. Whatever light you choose, you'll need a way to suspend it over your growing plants. A fluorescent light fixture will need to be mounted low over the plants, while a high-intensity light source can be positioned further away (so it doesn't burn tender shoots). In either case, be sure the fixtures can be adjusted in height over the plant trays.
Choose Your Space
As you can see, choosing your space is the first step in designing your seed-starting shelf. You will need to find a space where you can have a light that's also warm enough and free of drafts.
Depending on how much space you have and how extensive your seed-starting requirements are, you can choose one of several options for holding your propagation trays.
Use a Table
The simplest seed-starting system is a table that allows you to hang a single fluorescent fixture over it. You can also build a simple structure to hang a fluorescent light.
A table is best if you don't have a huge number of seeds to start. A typical folding table can hold roughly four to six propagation trays and you'll need two or three fluorescent lights over it. One set of fluorescent lights can grow two to four propagation trays of seedlings.
Use Metal or Wood Shelving
Industrial metal shelving is an inexpensive way to start many more seedlings than you can with a single-layer table. This type of shelving works best when you hang fluorescent shoplights from each shelf with 1-inch metal S hooks and chain. You can easily adjust the height of the light with the chain and hook. You can fit one or two fluorescent light fixtures on each shelf.
If you are handy with wood, you can build a seed starting rack yourself. Here are some plans to inspire you. If you have scrap wood you can recycle, this could cost less than the metal shelving. You could also customize the size more easily.
Add Plastic for Extra Heat
If you are starting seeds in a chilly garage or barn, you can take the industrial metal shelving setup and enclose it in clear plastic with some velcro or spring clamps. Add a small fan at the bottom for ventilation and be prepared to monitor temperature with a thermometer so that you can open and close the shelf system as needed.