Whether you have a few vegetable plants growing in containers on your patio or a large garden covering acres of land, you can save money and grow healthier plants by starting seeds indoors.
I started gardening 20 years ago when I grew vegetables in two tiny strips of dirt on either side of our patio attached to a rental townhouse. Now, with four acres to garden, I grow most of the produce my family eats in a year and have enough for family and friends. I start seeds indoors beginning in February and save hundreds of dollars each year by not buying mature plants from the local nurseries.

Which plants you should start indoors

Your hardiness zone and plant types will dictate which you should start indoors and which you can sow directly into the ground. If your state has a long growing season, you should start seeds indoors only for those plants that take longer to mature. For example, in zone 7b, peppers and tomatoes are best started in January or February indoors, while most other fruits and vegetables can be planted straight into the garden. Pay attention to the length to maturity or harvest so that you don’t start the seeds too early. You can look up your USDA hardiness zone here. If you are unsure when to start seeds for your climate, Margaret Roach has built a handy tool that should help you get it right.

Planting medium and containers

Seeds should not be started in dirt from your garden or cheap bagged dirt. Both can be home to bugs that will eat your seeds, or weeds that can grow in their place. Seeds need a light medium that consists of peat, sand and compost. Perlite or vermiculite are also used in some planting mixes in place of sand. I like to start seeds in a mix that is 2 parts peat and 1 part sand. I use both sand and peat in my garden which means I won’t have half used bags of anything sitting in the garage waiting for next year.
Seeds can be started in just about any container that is clean, sterilized and offers drainage. You can use a drill or nail to put holes in cans and plastic containers. Save stackable plastic planters from year to year, but before planting in them clean them well and sterilize them with a weak bleach solution to kill any soil contaminates. 

Grow lights, warming pads & humidity chambers

If you are lucky enough to have a large window that faces south, you can successfully start seeds without any specialized equipment. In a house bathed in shade or in colder climates you can speed the germination process by providing  warmth and light. You don’t need special equipment to germinate seeds. Covered germination chambers can sometimes lead to too much moisture which can rot seeds. To keep seeds moist use a mister to moisten the soil several times throughout the day.
I have two very large triple windows where I set up folding tables to hold pots of seedlings. The pots all rest in lucite or hard plastic trays with lips to catch water that seeps out of the bottom of the containers. These are easy to carry outside during the hardening off phase and they are easy to clean when it is time to store them.

How to thin

Thinning is best done using small manicure scissors. If you get seeds too close together like I did in the photo above, you can damage the tender hair-like roots of surrounding plants if you pull the unwanted seedlings. In a six inch pot you can safely leave four seedlings if you plan to transplant again before putting in the garden. Start in the center and snip out the unwanted seedlings and gently remove them from the container.

How to harden off

Hardening off refers to the process you take seedlings through to transition them from the gentle calm of their indoor climate to the harsh sun, wind and rain of their new outdoor location. This process will vary for different hardiness zones. In very cool climates young seedlings might be able to stay out most of the day if wind and rain aren’t a problem. In warmer parts of the country seedlings will only be able to go out during the morning and evening hours.
Once the seedlings are thinned and have two to three sets of leaves they should be hardy enough to spend some time outside. Water the seedlings before taking them out during the milder parts of the day. After a few days you can start lengthening the time the plants stay outside. Check the seedlings frequently if the sun is hot. If they begin to wilt, bring them back indoors and mist or water to help them recover. Once your seedlings are able to stay out all day without wilting they are ready to be transplanted.

When to transplant

This is another process that depends on your hardiness zone or date of last frost. If you have plants that have outgrown their current pot but it isn’t time to transfer them to the garden, replant them into larger pots so they don’t become too rootbound. If you aren’t sure when the threat of frost is over for your hardiness zone, you can check the Almanacs online to point you in the right direction.