How and When to Transplant Seedlings: 6 Easy Steps to Transplanting Success

Yes, you can transplant seedlings too early. This happens when temperatures are not yet consistently above 60F (15.5 C) during the spring, and a sudden frost or snow comes in.  

These temperature fluctuations can happen in the early fall as well. Here is an Instagram post from a veteran garden coach who experienced freezing temperatures rise to the 90sF (32C) in one week.

In the spring, it can be beneficial to "harden" your seedlings in trays outdoors for 1-2 weeks before transplanting the seedlings into the garden beds. Hardening means placing your protected seedlings or seedling tray outdoors to get used to winds and changing temperatures.

In the fall, hardening is easier to do and can be done in a few days, since the weather is warmer outdoors, and snow is generally unexpected.    

If snow or hale is possible, use a cloche or light row cover to protect fragile baby plants.

• As noted above, make sure that your seedling is about 2-3 inches high before transplanting.
• We also recommend transplanting a seedling after its two "true leaves" first come out. True leaves are the leaves that grow after the initial seed's cotyledon leaves come out. Not all plants have prominent cotyledon leaves. So transplant after you see at least two sets of leaves (four leaves) grow.

• Harden your seedlings outside before your transplant them. Even just one day of hardening helps. As state above, 1-2 weeks in the spring or a 1 or more days in the fall is best practice.
• If your seedlings become leggy (too long), that is a sign that they are outgrowing their current trays or pots and are longing for more soil to grow in. (It could also mean they are reaching for a light source.) If you cannot transplant outdoors due to temperature, transfer them into a larger tray or cell pot as soon as you can. Another word for this is "pricking." We recommend 4.5-inch deep square pots for "pricking" because they fit very nicely into the 1020 trays that we recommend for starting seeds.

• Transplant before, during, or after a rain event and take advantage of rain doing the watering for you. If rain is not in the cards, make sure to water the seedling tray and your garden bed heavily before you transplant.
• Transplant during the cooler times of the day to avoid "transplant shock." This practice is a perfect example of "working with nature" and not against it. If you transplant during rainy weather, you don't need to worry about watering your plant!

According to those who plant by the phases of the moon, the moon's "second quarter" (specifically, two days before the full moon) are the best times for transplanting crops that have their "seeds inside the fruit," such as beans, melons, peppers, squash, and tomatoes. These kinds of plants happen to be mostly summer crops. 

The Farmer's Almanac tells us that those crops we eat below ground, such as the roots and tubers of carrots, potatoes, and onions, grow better when transplanted during the "waxing of the moon," or after the full moon.  Biodynamic gardeners note that the moon's energetic action on plant growth below ground and above ground is in line with the moon's gravitational pull on the ocean tides' rising and falling. 

If you don't get this moon phase quite right, do not fret. The most important thing is that you actually transplant successfully during your seasonal windows of opportunity and do not let your seedlings die.

• A"dibber" - A "dibber" or "dibble" is any "hole poker" that you can use to make indentations in the soil to accommodate the plants' root system.

• Spade
• A watering can filled with water or hose with a nozzle spray
• Your seedlings

Note: If you are comfortable with it, you will be more successful transplanting seedlings using your bare hands. The roots of plants are fragile, and you'll need as much control as possible to ensure that they are kept intact in the process.  In the video below, Dave transplants using gloves because he had just suffered from a rash from poison sumac.

• • Using a dibber, make a hole in the soil deep enough so that one half of the plant and all of its roots are under the soil.

• • If your roots are long, make sure to not only make a hole but a shaft that goes down far enough so as not to compromise root growth during the transplant.
  • If your seedling comes in a biodegradable pouch that will break down and not impede root growth, make a hole large enough for the whole pouch. Use a space or shovel, as shown in the video. Doing this is an excellent way to keep "plant stress" at a minimum. Sometimes, these root pouches need to be broken up, and the roots freed and spread apart to help the plant grow optimally.

• • Heavily water the area you have prepared for the plant.
  • Heavily water the plant or seedling tray before transplanting.
  • Hold your plant by the "ears" or two true leaves and retain as much of the original soil around its root system as possible when you transplant.
  • Gently transfer the plant into your hole.
  • Cover the transplant with a good mound of soil so that one half of the plant is below ground, and the other half is above.
  • Water again.