The Beginner’s Guide to Starting Seeds Indoors

This is one of my favorite topics to write about. If you, like me, live in an area that has long and cold winters seed starting can be the little taste of spring we need on the long and dark days. Starting seeds indoors takes time and patience, but it’s not an overly difficult process. I have been starting seeds indoors for many years and have learned a lot along the way. I want to encourage you to try starting some seeds indoors… especially if you love gardening and get the classic “winter blues.”

Step 1: Determine your growing zone and average last frost date.

Learn your zone and average last frost date. This is very important when it comes to starting any seed indoors. I live in zone 3B, so my average last frost date is May 15th. You can easily determine yours with a google search. Mark that date on the calendar and keep your zone in the back of your mind. You will want to make sure that whatever seeds you start are appropriate for your growing zone.

Step 2: Determine what seeds to plant.

Honestly, I find this to be the most difficult part of the seed starting process. There are so many different things that can be grown and so many varieties of each thing! My best advice is to check the growing zone to make sure it is appropriate for your area and read the seed descriptions. It can also be helpful to keep a record of what you liked and didn’t like to help when picking out seeds the following year. I love to start seeds and start thousands each spring, but when I first began I only grew tomatoes and a couple of other things from seed and got the rest from a local greenhouse. Start slow and learn… it becomes addicting very quickly!

Step 3: Determine when to start the seeds.

Not all seeds need to be started indoors. Check the directions on the seed packet to determine when and how to plant the seeds. For example, zinnias can be directly sown into the ground or started indoors four weeks before the last frost. I choose to start them indoors due to the short growing season here in Northern Minnesota. Take your calendar marked with the last frost date and count backwards each week to determine when to plant your seeds. I like to physically label my calendar with the weeks to last frost. So with my last frost date of May 15, I write a “1” on May 8, “2” on May 1, etc. and continue it to the start of the year. I start my first seeds here in the beginning of February, but the majority are started 6-8 weeks before last frost (so sometime in March). I like to add the seed variety to my calendar on the appropriate week for planting when they first arrive so it is easy to know when they need to be planted! I explain this process in further detail in this post.

Step 4: Create your growing space.

For best results, I would highly recommend using artificial light and not just placing plants in a window. While the window can work for some types of plants, most will require additional light to avoid them becoming “leggy” (long, thin, weak stems). I started out with this LED Grow Light Setup, and continue to use it now! When I expanded my growing area, I purchased 5000 lumen LED shop lights instead of specific grow lights and they work great as well and have a much lower price tag. I also like to use a timer for my grow lights so I don’t need to remember to turn the light on and off. I usually start with my lights on for about 12-14 hours and adjust as needed and keep lights about 6-10 inches above the plants.

Step 5: Plant the seeds as scheduled and follow care directions.

Plant the seeds as directed on the seed packet using a high quality seed starting mix. I usually use the Miracle Gro seed starting mix. Moisten the dirt prior to planting your seeds. The dirt should be moist but not soggy. The easiest way to test this is when grabbing a handful of dirt and squeezing, it should clump together but not drip. You can use seed starting trays, egg cartons, or old containers. Just be sure that they are clean and don’t use anything that had something harmful or toxic in it prior. My rule of thumb is to use seed starting containers or old food containers because I know that they didn’t have dangerous contents before. Once the seeds are planted, cover them with a humidity dome if you have one (not completely necessary but very helpful to maintain humidity and moisture levels) and place them under your grow lights! Be sure to check a couple of times per day to water (bottom water only) or mist as needed to ensure the soil does not dry out! Once the seeds have sprouted, remove the humidity dome. As the seedlings grow, use a fan on low to introduce the wind to the seedlings which will help with airflow and help to strengthen their stems.

Step 6: Begin to introduce seedlings to the outdoors (harden off).

As the days get warmer and spring fever kicks in, it can be very tempting to bring all your seedlings outside… don’t. They need to be introduced slowing to outdoors to become acclimated to the different environment. Acclimating, or hardening off, is done over a week or two. Start by bringing seedlings outside to a protected area for about an hour then bring them back in. Slowly increase that time (two hours the next day, then three, and so on) until they are able to remain outside. Be sure that the temperature is appropriate for your seedlings. For example, snapdragons can handle cooler weather but tomatoes require temperatures above 50F. It is important to acclimate your plants to the outdoors prior to transplanting them outside.

Step 7: Plant seedlings in pots or garden.

Once the last frost date has passed, the temperature is appropriate, and you have acclimated your seedlings to the outdoors it is time to get planting!

Don’t be discouraged if some of your seedlings don’t make it. I kill plants every year and always will! It is part of learning but also not all seeds will germinate. Just keep trying, keep learning, and keep growing! You got this! 🙂