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Natural Awakenings Milwaukee Magazine

Indoor Seeding to Win This Midwest Gardening Season

Feb 01, 2023 12:40PM ● By Tiffany Hinton
Tiffany Hinton-Cutivating Guts-seed starting

Photo credit Tiffany Hinton    

It is the time to plant this year’s summer garden seeds indoors. In zone 4 and 5, February is the perfect time to start seeds for cool weather crop plants like broccoli and kale to be ready to transplant into the backyard garden or pot after the last frost of the season. It is also a good time to start tomato and pepper plants, so that they can be easily transplanted in May.

This year, the last frost is predicted to be April 25, according to The Farmer's Almanac for the Chicago area. Easily check the last frost date prediction for your zip code at On average the last frost day for zone 5, which is where Chicago is located, is May 15; therefore, the last frost date can change from year to year.

If indoor seed starting is new for you, these tips will make the steps simple and achievable. The biggest thing to keep in mind is that growing seedlings is fun, and not a perfect science. Enjoy the process, get the kids involved and prepare for a bit of a mess. Put on some play clothes and let’s get to planting.

Prepare ahead of time by having seeds, planting trays and seed starting soil gathered.

Step 1. Read the seed packets to understand time to germinate, if light or heat is required to germinate, along with how many weeks to plant prior to last frost date. If you do not have a grow light, placing the seed trays in a windowsill is a great alternative. Similarly, if a heat is required to germinate, place the seed tray by a heat vent to replace the need for a heat mat. For example, celery, peppers and roman chamomile require heat to germinate. All seeds will require even humidity and moisture.

Create the Soil Mixture

Photo credit Tiffany Hinton

Step 2. Moisten the soil mixture using water. The soil needs to be wet, although not the consistency of mud. A good way to test for appropriate moisture is if the soil packs together easily. One cup of water to one quart of soil is a good estimate. Gently and firmly pack the soil into each seed cell of the tray. Using a pencil, chopstick or other tool, poke a hole in the soil in each cell to the depth suggested on the seed packet. Add one seed to each cell and gently cover with soil, making sure the seed makes good contact with the damp soil mix. Some varieties of seeds will require more or less of a soil cover, always read the packet. Label trays using a permanent marker. Gentle water or mist and cover with plastic dome. Plastic wrap can be used in replacement of the plastic seed tray dome to create the humidity required. Place trays in a warm place above 70 degrees F for tomato and pepper seed germination. Refer to the seed package for the proper temperature.

Keep the Seedlings Watered

Step 3. When the first two seedling leaves appear, remove the plastic dome or plastic wrap to prevent the seedling from molding or “damping off”. Move to a location with light and temperatures between 60 and 65 degrees F. Water from the bottom if possible to encourage the roots to grow down. Watering should only be done when the soil feels dry, not looks dry. If you are using a window for light, once a week rotate the seed tray so that the plants to do bend toward the light. A grow light directly above is a good investment as it can be adjusted in height as the seedlings grow helping to prevent spindly stems.

Harden Off the Seedlings

Step 4. When plants are large enough and two weeks prior to transplanting outside, it is time to start hardening off the seedlings by placing them outside during warm days for four to six hours, extending the time as the transplant time comes closer. In the case of the seedlings growing quickly and tall, or gaining robust roots the plant can be transplanted into a 4 inch cup or large Solo cup with holes poked in the bottom for drainage until it is time to plant outside.

The three biggest needs for a seed to be successful is proper temperature, water and light.


Additional gardening and seed starting information can be found at Author Tiffany Hinton offers a free gardening planning online class and helpful gardening education. The next class for Hinton’s kids gardening club, the Little Witches Moon Gardening Club, is February 11. She invites you to register your child for the garden club by visiting