Too Cold to Garden? How to Start Seeds Indoors for Spring
While it may be cold outside, you can still enjoy your love of gardening by starting seeds inside your home in preparation for the warm weather ahead. Keep reading to find out how to grow seeds indoors, when to start, and what you’ll need.
Step 1: Prepare Planters
Timing is critical. If you start your seeds too soon, they may grow out of their containers before spring arrives. Start them too late and they won't be ready in time. A good rule to follow is to start your seeds about eight weeks before the last expected spring frost. Consult your local weather channel or conduct an Internet search for the almanac forecast in your area.
Choose a starter planter with proper drainage. Get creative! Seed flats, peat pots, plastic cups, egg cartons, even takeout boxes with holes poked in the bottom work well. In general, your planting containers should be at least 3" to 4" deep. Fill them to about 1/4" from the top with soil.
Egg cartons and peat pots need to be soaked in water before adding soil and seeds or they will draw moisture out of the soil.
Step 2: Get Good Planting Soil
The soil you use should be healthy and free of debris, insects, and other seeds. The best type of soil for starting seeds is commercial potting soil or germination mix, which can be found at your local True Value® hardware store. These planting mediums are sterile, free of weed seeds, and have the right amount of nutrients for newly emerging plants.
Your soil should be lightweight and full of air. Soil-less mixes containing peat or peat moss have excellent moisture retention and stay moist longer. Perlite and vermiculite have the same effect. If you want to make your own soil mixture at home, use one part loam, one part clean sand, and one part leaf mold or moist peat.
Certain types of fungi can make indoor gardening go awry, so make sure the soil you choose has been sterilized.
You can sterilize your own soil by heating it in the oven or microwave with a medium-sized potato. When the potato is baked, the soil is ready to seed.
Step 3: Plant Your Seeds
Use a tray to hold your starter containers. Line the bottom of each container with paper towels to keep the soil in while allowing water to drain out. Fill the containers with the potting mix then spread seeds evenly about 1" apart. Use a pencil to make holes two to three times the size of the seed. Then cover the seed with a thin layer of soil, misting the top with water.
Step 4: Let There Be Light and Water
Check the packet instructions to determine how much light your seeds need to germinate. Some seeds need little or no light to sprout while others require a great deal. To help your seeds germinate, keep them in a warm area. Don't let it get too hot — excessive heat can kill emerging seedlings. Covering the planters with plastic wrap will keep them warm and moist, helping them germinate. Be sure to remove the plastic wrap as soon as the plants' sprout. Once the seeds germinate and shoots emerge, move them to an area that stays at room temperature. Water your new sprouts daily with a light mist, being careful not to over-water.
Step 5: Keep Seedlings Healthy after Germination
After the seedlings germinate, they will need a lot of light to survive. Place them in a naturally sunny window, or purchase fluorescent grow lights to supplement the amount of light your seedlings receive. If you're using fluorescent grow lights, place your planters 3” to 4” away from the light source for at least 14 hours a day.
To keep seedlings from drying out, place your planters on a large, raised pan with a bed of gravel spread across the bottom. And add water to the gravel, being careful to keep the water level below the plant containers.
Step 6: Fertilize Your Seedlings
Monitor your seedlings' growth carefully to know when to start fertilizing. The first leaves that appear will be food storage cells called cotyledons. Wait until the first true leaves sprout and then use a quality liquid fertilizer — available at your local True Value hardware store — to keep your seedlings healthy. Use a weakened solution (diluted to half the recommended strength) once each week.
Step 7: Harden Plants Off
Now you'll want to harden off the plants, which means to acclimate them to the outdoors. When temperatures rise to the 50s, place the seedlings outside in a shady spot for half a day. Slowly work your way up to leaving the seedlings outside for two or three full days. Gradually move them into full sun. Don't put them out too early, as you don't want any late winter frosts to kill your new plants.
Step 8: Transplant Your Plants
Generally, seedlings are ready to be planted four to six weeks after seeding. If outdoor frosts linger or the seedlings outgrow their original containers, transplant them into a larger pot until they're ready to be planted outdoors.
When you are ready to transplant your seedlings, water the ground and the seedlings thoroughly. Use a trowel to dig a hole about twice the size of the root ball. Set the transplanted seedlings in gently, covering them and leaving 1/4" of soil pressed firmly around the roots. Leave a small depression around the plant stem to help trap moisture. Water daily or according to seed packet instructions.
Good job! Now your new plants will flourish ahead of schedule.
Project Shopping List
Here’s what you’ll need to complete this project successfully.
Commercial potting soil or germination mix
Loam, clean sand and leaf mold or moist peat (optional)
Medium-sized potato (optional)
Plastic wrap (optional)
Fluorescent grow lights
A large pan filled with gravel (optional)
Large pot (optional)