From Seed to Garden: Master the Art of Transplanting with These Essential Tips

Seedlings grown in nurseries live sheltered lives. After seeds germinate, the resulting baby plants are kept in controlled environments with just the right conditions, from temperature to light, to develop healthy roots and thrive in the future. 

Even when seedlings “graduate” from the nursery, they’ll still need some extra help before they’re ready to live in your garden. That assistance should include hardening them off: preparing your plants to transition from the nurturing environment they enjoyed in the nursery to not-so-gentle real-world conditions.

“If the seedlings are put from their little sheltered world out to this harsh world without getting some acclimation to it, they can suffer damage,” Vego Garden Horticulturalist Carol Childres said. “You’ll usually need to spend about seven to 14 days before transplanting them when you’re gradually exposing the seedlings to varied temperatures, outdoor light, maybe some wind.”

The hardening-off process is important, but it’s not the only thing you can do to improve your newly purchased seedlings’ chances of thriving outdoors. The soil and fertilizer you provide—and even the way you handle them when you’re planting them in your garden—will make a difference, too.

Here’s a closer look at the measures you can take to help your seedlings reach their full potential in your garden.

More on hardening

So, what does the hardening process involve? Basically, it’s a period when you’re allowing your plants to adjust to outdoor conditions gradually.

Childres recommends putting your plants outdoors for a few hours at a time during the first few days you have them and then slowly increasing the time. 

Hardening for seven to 14 days is recommended, but that timeframe isn’t written in stone. You may find that after a couple of weeks, the conditions outside are still too cold or harsh for your tender seedlings.

If that’s the case, extend the hardening time: Give your seedlings outside time, but hold off on planting them in your garden. You can always put them under a cold frame during their visits outdoors, which will help protect them from frost damage while they continue to acclimate. If your hardening time runs longer than expected, your seedlings probably will continue growing, and you may need to transplant them into bigger containers. 

If you want a better idea of when the risk of spring frosts is minimal in your area, check with your local extension office.

A word on watering your seedlings during hardening: You want their soil to be damp, not sopping wet. It’s OK to let the soil dry out a bit between waterings.

Soil prep

While your seedlings are getting ready for your garden, you can work on getting your garden’s soil ready for the seedlings.

If you’re putting the seedlings in a container, you’ll want a good potting mix to put them in. If you’re putting your seedlings in the ground, make sure the soil conditions are optimal. If the dirt has a heavy clay component, for example, you’ll need to break it up and work in compost. It will be important to create soil conditions that provide the nutrients for your seedlings along with enough room for roots to grow, breathe, and absorb moisture.

If you’re planting in raised garden beds, you can create optimal conditions by building layers of soil and organic, recyclable materials.

When it’s time to transplant

OK, your seedlings have been hardened off, the soil is ready, and you’re fairly confident the last freeze of the season is behind you. It’s time to welcome your seedlings to their new forever home in your garden.

Removing seedlings from their containers requires care. Try turning each container upside down and cradling the root and surrounding dirt (root ball) in your hand. Then, lift off (or cut away) the container. As you place a seedling in the ground, handle it by its root ball or, if necessary, its leaves. Never hold a seedling by its stem; you could seriously damage the plant.

If your seedling is root-bound, meaning its roots outgrew their space and wound themselves around their root ball, gently break the roots up a bit to loosen their grip. This process will not harm your seedling.

Childres likes to add organic fertilizer pellets in each hole (about 1/2 to one teaspoon) and put the root ball right on top of that. It’s not going to burn the root and it has microorganisms that help the root establish. Take care, though, to research the fertilizer needs of each type of plant in your garden, so you can select the right formula.

Don’t place your seedlings down too deeply in the soil; the dirt shouldn’t cover more than their lowest set of leaves. Aim for about the same level of coverage they had in their original containers. 

Once you place your seedlings in the soil, gently fill the holes you’ve dug with quality soil and compost. Then, water around the base of each seedling lightly.

If you’d like, you can toil the soil with a thin layer of uncolored mulch, which helps hold in moisture and minimize weed growth. 

Caring for your planted seedlings

When you water the seedlings you’ve planted, water around their bases, not over their leaves and stems. Even with rain landing on the plants, limiting your watering to the soil will help prevent mold and diseases, Childres said.

A key to helping your seedlings stay healthy after planting is taking care not to under- or over-water them. Check the soil and water as needed to ensure it is moist, but not soaked.

Ideally, Childres said, aim to soak your garden soil as needed. If you water lightly every day, you run the risk of creating soggy soil and damaging your plants’ roots.