Basics for Starting Seeds Indoors for Transplant Outdoors

Seedlings grown indoors will need warm temperatures, a well-drained media with correct pH to grow the plants, strong light (supplemented artificially), proper nutrients, correct water amounts. Steps to do this are, first, select disease-resistant varieties of seed. Such seeds are more likely to lead to successful harvest.

To determine the date on the calendar to start the seed indoors, for growing transplants for the outdoor garden, find out when the last frost date is in your area. Transplants started indoors should be able to be planted outdoors about the middle of the month of May.

bachelor button seeds

Bachelor Button Seeds, Andrea Stith, University of Kentucky

1.) Choose the last frost date
2.) See the number of days on the seed packet from seed to germination
3.) Add this number to days to flower on the seed packet
4) Count back from the last-frost date on a calendar
5.) See the date that coincides with this on the calendar. This activity should give the gardener the date to start seeds indoors.

For gardeners anxious to start flowers from seeds, help can come from constant-warmth for the growing medium by adding bottom heat. A heat mat uses electricity to warm the soil or growing medium of shallow containers, such as starter flats. To do this, the flats are placed on the functioning heat mat and left until seeds are sprouted to the first true leaves. This bottom heat is frequently beneficial even when seeds are started indoors in a warm room.

As for supplemental light, successful gardening can use a plain, cool-white fluorescent bulbs in a shop-light fixture, located 5 to 10 inches above the foliage. Grow-light bulbs can be beneficial if budget allows.  Hang the shop light by chains to allow lifting of the fixture as the foliage grows taller.

Thinning seedlings is best if they are crowded. Over-crowded stands produce weak plants. Scissors can cut off extra seedlings at the soil line, without disturbing the stand of desired seedlings. Or, it may be possible to save some of the seedlings instead of cutting them back by gently pulling the seedling out. If seedlings can be lifted out of the soil so that most all roots remain intact and the rest remain in good shape, those lifted may be transplanted.

Once the desired size and outdoor temperatures allow, take plants outdoors to harden off. Seedlings will need to go through a toughing period called “hardening off” before planting outdoors. About two weeks before planting, take the seedlings outdoors in the daytime. Bring them in at night to strengthen them, so plants may be able to withstand the new environment. Remember to cut back on water and fertilizer during the last week of hardening off.

After this, gardeners may transplant to a suitable site. To transplant, handle transplants by the leaves. Plants can grow new leaves, but cannot grow a new stem. Use a pointed object to poke a hole in the growing medium and gently direct the roots of the seedling into that hole. Holding by a leaf, carefully firm the soil around the stem, keeping the soil line the same. Water in. Gently firm the soil around the root zone. Be mindful of fertilizer application and water as needed.

Submitted by Kathryn Wimberley McCracken County Agent for Horticulture/covering ANR