You can make your own pots by poking drainage holes in plastic yogurt or sour cream containers. Make sure there are enough holes so water drains quickly. Before using, sterilize containers by soaking them in a water bath with 10 percent bleach.
Seedlings will need a bright spot in which to grow. A south window may work if it is well-insulated from spring chills, but a shop or plant light is more reliable. Most seeds want bottom warmth to germinate. If you don't want to spend money on commercial heat mats, placing trays on top of a radiator or next to a heat register also works.
Now for the fun part: choosing seeds! Big seeds are usually easier to start. Annual seeds like marigolds, zinnias, bachelor's buttons, cosmos, morning glory and cleome are easy to handle and can be planted in mid-March. Seeds with very hard outsides, like morning glories, benefit from being nicked with a knife and soaked in water for 24 hours before they're planted, to aid sprouting. Among vegetables, tomatoes and broccoli can be started indoors in the next few weeks.
This is where you need to temper your enthusiasm and look to directions on the backs of seed packets for guidance. While we're all eager to start gardening, planting seeds too early will leave you with spindly, weak plants instead of sturdy, vigorous seedlings. Information on the seed packets will tell you when to plant seeds, how deep to plant them and how long it will be before seedlings pop out of the soil. Packets often direct gardeners to plant seeds "eight weeks before last frost date" or something similar. In the Twin Cities area, that means counting backward from about May 10, so mid-March is a perfect time to get started.
I cover newly planted seed trays with clear plastic wrap to conserve moisture. When seeds germinate, the plastic comes off. Marigolds pop up in just a few days, while many other seeds take up to two weeks. Again, pay attention to the directions on seed packets. Once when I had bad luck starting annual gomphrena (globe amaranth), I realized that my seeds should have been in total darkness to aid germination. I replanted, covered the pots with sheets of cardboard and had better luck the second time around.
Once your seedlings are up, move the trays to a bright spot or under lights that can be raised and lowered. To grow sturdy plants, lights should be 2 to 4 inches from the tops of seedlings and raised as the plants grow. If lights are too far above plants, your seedlings will stretch for the light, and stems will be weak. Lights should be on about 16 hours a day. Many plants need darkness each day, so putting the lights on a timer helps.
