How to Transplant Seedlings

Whether purchasing starts from a local nursery or sowing vegetables seeds indoors prior to the growing season, transplanting will be an important step in the creation of your vegetable garden. The key is to minimize the risk of transplant shock, which can stunt the plants’ growth, affect their quality, and cause disfigured leaves and tiny fruits and flowers. Here’s how to transplant seedlings in order to ensure a successful crop for many different types of plants.

TRANSPLANT THE HEALTHIEST SEEDLINGS
When buying starter seedlings at the nursery, choose only the healthiest ones. Leaves should not be yellowing, wilted or otherwise discolored or unhealthy looking. Examine them closely to be sure they have not been infested with insects; check for bitten or damaged leaves and stems. Check for spots and any sign of mildew or disease. Avoid tall, spindly plants, which probably did not receive enough light and are already under stress.

This goes for homegrown seedlings too, particularly when choosing which young plants to keep. Do not transplant diseased or insect-infested seedlings alongside healthy seedlings.

HARDEN THEM OFF
Always introduce seedlings to the outdoors gradually. This is the best way to avoid transplant shock. Begin by bringing them outside during the day only. On the first day, leave them out for just a few hours. Increase the amount of time you leave them outside each day for at least a week to 10 days, before planting them into the garden. The day before you transplant, leave them in their containers outside overnight before you set them into the ground. This goes for container vegetables being transferred into larger outdoor pots as well.

DO NOT TRANSPLANT TOO EARLY
Most vegetables should only be transplanted only after the danger of frost has passed. If you are starting vegetables indoors and have sufficient space and light there is no reason not to play it safe. Find out the last average frost date for your area but it is even better to find out the safe date. The safe date is when 90% of the time no more frost will occur. Some young seedlings (three weeks and older) like broccoli and cabbage, will bolt prematurely if exposed to temperatures 40° F and cooler.

LET THE SEEDLINGS MATURE
The more the seedlings can become established, the stronger roots they can develop, the better suited they will be for transplant. Be sure they are at least as tall or old as recommended before transplanting outdoors.

DO NOT DAMAGE THE ROOTS
Take great care not to damage any part of the roots, including the very tips, which are most responsible for absorbing water.

MULCH TO WARM THE SOIL
Black and clear plastic mulch can be used to warm the soil prior to transplanting. Be sure they are snug against the ground to maintain the most warmth and moisture and to effectively kill any weeds.

WATER BEFORE TRANSPLANTING
Always water your seedlings prior to transplanting. You do not want the roots to dry out, which can happen in as little as 3 minutes of exposure.

TRANSPLANT INTO MOIST SOIL
Give your garden bed a good soaking before setting out transplants.

TRANSPLANT ON AN OVERCAST DAY
Another way to prevent seedling roots from drying out is to avoid transplanting when it is too hot or sunny. When possible, choose an overcast day and transplant in the morning. A calm, windless, rainless day is also best. If an overcast day is not possible, transplant in the late afternoon so the plants can avoid the harsh, direct sunlight of the mid day, or plant them in the morning and shade them during the hottest part of the day from direct sunlight.

SET AT PROPER DEPTH
Do not set your transplants too deep or too shallow. Most will want to be set at the depth they sat in their starter pots or just a little deeper. Some vegetables, like tomatoes, can be set very deep. In general, bury up to the first set of leaves unless instructed otherwise. This will allow a strong root structure to be established. For tomatoes, you can even remove the bottom set of leaves and bury even deeper.

USE BIODEGRADABLE POTS
Sow your seeds in biodegradable pots. They will tear away from the soil quite easily upon transplanting, allowing minimal conditions that may damage or expose the roots. Coconut fiber pots and homemade newspaper pots work well.

WATER RELIGIOUSLY
For the first few weeks after transplant, it is critical that you provide the correct, consistent amount of water for your seedlings. In most cases, the soil should be kept evenly moist without ever leaving it muddy. Establish a regular water routine and stick with it. Use the finger test to determine when the soil is dry and inch deep and water at that time.

STAKE TALL PLANTS

If your seedlings are tall and tipsy, stake them when transplanting to help avoid further stress on the roots. This will be necessary for indeterminate vegetables anyway, but non-vine plants can benefit from early staking after transplant as well.

AIR POCKETS

Check the soil around each seedling the first few days after transplant to be sure no air pockets have developed, which can dry out the roots.

Do you have tips or questions on how to transplant seedlings? Let us know in the comments section below.

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