Starting vegetable or ornamental plants indoors from seed is a great way to neutralize the last of the winter blues. It also provides a greater selection of vegetable or flower varieties than what is available at the local nursery. After germination, the next step is to prepare your seedlings for the outdoors.

When to Transplant

A few weeks after germination, your seedlings may be ready for transplanting, but the weather may be unsettled yet. In southern Ontario, the last spring frost usually occurs in May. It does not hurt to wait a bit longer before moving your seedlings to their permanent home however.

Counting True Leaves

If full-spectrum grow lights were used after germination, then your seedlings are likely to be robust. Seedlings grown without lights or a sunny window may be tall but a little stringy. Knowing when your seedlings are ready for transplanting is easy though.

Count the number of true leaves on each plant. True leaves are leaves that form after the cotyledons, which are the first two leaves you see immediately after germination. The cotyledons are rounder and thicker than the true leaves that emerge later. If you count four or more true leaves, then the seedling is developed enough for transplanting.

Hardening Off

Preparing your seedlings for life outdoors is accomplished via a process known as hardening off. Hardening off allows the seedlings to adjust gradually to full sun and varying temperatures. The first step is to withhold fertilizer. Over a week to 10 days, set the seedlings outdoors during the day away from wind and full sun. A cold frame is ideal for this period. Day by day, allow the seedlings more sun except for any plants that happen to thrive in shade.

Transplanting Steps

After hardening off, your seedlings are more robust but still fragile. Take care when handling them to avoid damage to the stem or roots. Wash your hands before handling them to eliminate any damaging plant pathogens.

Prepare small holes in the outdoor garden with spacing appropriate for full size plants. Make the hole a few inches deeper than the length of the root ball and fill it halfway with the same soil used to grow the seedling. Carefully suspend the seedling in the hole and place soil around the roots until the hole is filled. Press the soil around the seedling gently but firmly so that there is a small basin around the base of the plant.

For the first couple of weeks after transplanting, apply liquid fertilizer sparingly. The fertilizer should be half-strength compared to what you would apply to a mature plant. Keep an eye on your new plants to make sure their roots are moist but do not overwater them. Some drooping is normal after transplanting and during mid-day.

Transplant Later Rather Than Sooner

Do not be too eager to transplant seedlings outdoors. Waiting for warmer, drier weather increases the chances for lush, healthy plants. Planting too early may diminish their ability to fight off disease.

If you have a transplanting question, or are in need of garden supplies, visit Van Beek’s Garden Supplies today.