Starting Plants From Seeds Indoors

By Melinda Myers - horticulturist and gardening expert
March 6, 2017

Warm up your green thumb for the garden season by starting a few seeds indoors. And don’t worry if you are new to gardening, this is a fun way to get started.

Try starting some long season vegetables like tomatoes and peppers or flowers like zinnias and marigolds to transplant into the garden when the weather is right for planting. Or grow some of the new or harder to find varieties. Many new introductions or heirlooms are not sold as plants in garden centers. So you either wait for them to become more popular and available for sale or start your own from seeds.

Pink Zinnia

Start by perusing the seed racks at your favorite garden center or check out the many seed catalogues, most of which are now on-line. The back of the seed packet or catalogue description will tell you the best time to start the seeds indoors for your area. They also provide any special planting directions you need to know.

Always plant seeds in clean containers and sterile planting or seed starting mix. You will avoid disease problems and increase your growing success. Disinfect used flats and pots by soaking them in a one-part bleach and nine parts water solution for ten minutes. Rinse with clear water before planting.

Fill the clean containers with the seed starting mix you selected. Plant two seeds per pot for insurance or multiple seeds in rows when using a large shallow container, flat. Gently moisten the potting mix so you don’t wash away the seeds. Loosely cover the containers with clear plastic to help keep the soil moist and extend the time between watering.

Or start seeds in compressed peat pellets. Soak these in warm water and watch them expand. It’s actually pretty cool. Once the pellets are full size you can plant your seeds.

New seedling in a flat.

Place the planted containers in a warm location. Most seeds need warmth and moisture not light to sprout. Water often enough to keep the potting mix evenly moist. Be patient as it can take anywhere from one to three weeks or more for seeds to sprout. Timing depends on soil temperature and the specific plant you are growing. Check the seed packet for the average time between planting and sprouting.

Move your containers to a sunny location or under artificial lights as soon as any green appears. Regularly turn pots growing in the window to encourage even growth. Since most of us do not have sufficient light to grow healthy stout seedlings adding artificial lights can help. Keep grow light 4 to 6 inches above the top of the seedlings. This means you will be raising the lights, or lowering the plants as the seedlings grow.

You will need to thin seedlings planted in containers or move seedlings to individual containers if started in flats. Wait for the seedlings to develop two sets of true leaves. These are the leaves that look like those of the plant you are growing. Once the plant has two sets of true leaves remove the weaker of the two started in individual pots. Move strong healthy seedlings from flats to their own container with a fork or similar utensil.

Continue watering often enough to keep the soil evenly moist but not soggy. Once the thinned and transplanted seedlings start growing you can start fertilizing. Use a dilute solution of a flowering houseplant fertilizer every two weeks.

Check the seed packet or your local Extension service publications for the best time to move your plants into the garden. Timing varies with weather and the plants tolerance to cool air and soil temperatures.

Prepare your plants for their outdoor home. Stop fertilizing and allow the soil to go slightly drier before watering again. Set the plants in the shade or other sheltered location. Move them into the sun for an hour the first day, two hours the next and so on until they have adjusted to the sunlight. A wagon or snow sled makes this job easier. Cover or move your plants indoors if frost is in the forecast.

In the meantime, prepare your soil for planting. Once the soil is prepared, your plants are conditioned, and the weather is right start moving your plants to their outdoor location.

So clear out a space indoors, purchase seeds, gather your supplies and get growing.