How to Transplant Seedlings Outdoors

Whew! Your hard work and dedication has turned teeny-tiny seeds into thriving mini plants. While that's certainly a reason to celebrate, a plant parent's work is never really done. Your next mission is to set your seedlings up for success on the second part of their journey: life outside. Transplanting seedlings isn't as simple as just putting your little guys into the ground, but it isn't complicated, either, with the right know-how. Here's how to transplant your seedlings.

Psst: haven't planted your seeds yet? Start here!

Avoid Transplant Shock and Damage

Once you experience the excitement of those first tiny stems sprouting up from the soil, it can be easy to get ahead of yourself and want to rush them outdoors. But it's better to take cues from your plant kiddos and let your seedlings tell you when they're ready to transplant. Here are a few tips that can help you better understand seedling speak.

• Know the difference between cotyledons and leaves. Those thrilling first one or two leaves that appear? Sorry to burst your bubble, but they aren't really leaves. They're cotyledons, which are also known as embryonic or seed leaves. They're thicker and harder than true leaves, which will grow later and resemble the foliage of a mature plant. You'll want to wait until you have at least 3 or 4 true leaves before you consider transplanting.
• Work with your plant's weather preferences. Understanding whether you're growing cool-weather or warm-weather plants will help you determine when it's time to start thinking about growing outside. For example, veggies like broccoli and kale can tolerate a light frost, while tomatoes and peppers need to be kept indoors until the threat of frost has passed. To determine when it's safe to put your plants outside, check your local frost date. For either type, if any late-season storms or unpleasant weather is headed your way, hold off until it's passed.
• Give extra TLC to seedlings grown in water. Seeds planted in a hydroponic unit will sprout faster since they're in a growing environment with all the water, nutrients, and light they desire. This also means the roots will initially be thinner and weaker than those grown in soil. You'll want to transfer the seedlings to small pots filled with potting mix as soon as they develop their first set of true leaves. This will give roots time to toughen up before they head to the Great Outdoors.

Fix Leggy Seedlings

If your seedlings look spindly and scrawny, it's best to address it before moving them outside, where they may struggle to withstand the elements. Leggy seedlings can be caused by a number of factors, including not enough light or water, or too much water or heat. Try to pinpoint the cause(s) now, while they're still indoors, by experimenting with more or less of these factors, and see if that helps.

Upgrade Their Space

If you sowed your seeds a little early (it's easy to get excited!), or unexpected weather is keeping them inside longer than planned, consider giving your seedlings more space to spread

out before transplanting them to their final destination. You'll know they're ready if their cotyledons are turning yellow, they've already grown one or two sets of true leaves, or their roots are growing through the drainage hole in their seed tray.

It's easy to upgrade their abode: Clean paper coffee cups, tin cans—anything you can add a drainage hole to—are fair game. You can also use this method if you plan to keep your plants indoors or in containers.

1. Fill your container 1/3 full with potting mix. Which potting mix you use depends on your ultimate goal. We recommend Miracle-Gro® Moisture Control® Potting Mix. This mix prevents over- and under-watering. (If your plant is staying indoors, use Miracle-Gro® Indoor Potting Mix, which is specially formulated for a wide variety of indoor plants.)
2. When you remove your seedlings from their tray cells or containers, tug them gently from the bottom of the stem. Separate any tangled plants gently. You don't want to damage those new roots or the top growth of your plant.
3. Place each seedling in its pot and cover the roots with more potting mix. Press lightly.
4. Water lightly and let drain.

If your plant is taking up permanent residence in a pot, choose a container that's slightly larger than the seed starting container. Once your plant has outgrown the second pot, move it to a container that will accommodate your plant's expected mature size (you can find information on the seed packet). If you plan to move your container outdoors, remember to harden off your plants before leaving them outside permanently.

Harden Off Your Plants

Once you've gotten your seedlings in tip-top shape and the weather looks favorable, it's time to start the process of hardening off. This involves gradually exposing plants to outdoor conditions to reduce the risk of transplant shock. They'll start creating firmer plant tissue, which they'll need in order to grow in a world of rain, wind, and hot sun. Trust us, your plant babies are going to be OK!

So, how do you harden off seedlings? Follow these steps, and before you know it, they'll be ready to graduate to the garden plot.

1. One to two weeks before you want to plant them in their permanent homes, start bringing them outdoors to acclimate.
2. Begin by placing plants in a well-shaded spot for a couple of hours on the first day, then slowly build up the amount of sunlight and hours of outdoor time they receive each day.
3. Be sure to bring them in each night.
4. Don't put plants outside if temps are forecasted to dip below 45°F or if strong winds or snow are expected.

Prepare The Soil

Prep your soil for its soon-to-be residents. Chances are, the earthy goodness you're going to settle your seedlings into will need some help. For in-ground garden beds, make sure the soil isn't compacted—use a rake or tiller to loosen it up if it is—and then mix 3 inches of Miracle-Gro Organic™ Raised Bed & Garden Soil into the top 6 inches of native soil to improve the composition and nutrition.

Planting in a raised bed also requires making sure the soil is ready for a great growing season. Start fresh or top off the existing soil with Miracle-Gro Organic™ Raised Bed & Garden Soil, which is lightweight enough for raised beds.

Transplant Seedlings

Finally, after weeks of growing, nurturing and preparing, the big day is finally here. It's time to transplant your seedlings! Try to transplant when it's cloudy so plants don't face a full day of direct sun right away.

1. For each plant, use a hand trowel to dig a hole just deep enough for the root ball to fit. Refer to your plant's seed packet for how far to space out plantings. They may look pretty far apart at first, but they'll be filling the entire plot before you know it.
2. Remove your seedlings from their tray cells or containers. Make sure the soil in their plugs or pots is moist before removing your seedlings. Then, gently pop the plants out by pushing on the hole in the bottom of the container with your finger, or use a butter knife or other tool if they're stuck.
3. Carefully place seedlings in their planting holes and cover their roots with soil.

Once your seedlings are nestled gently into the soil, you'll need to water them immediately. Add Miracle-Gro® Quick Start® Planting & Transplant Starting Solution to your watering can for the first watering (follow label directions). Water again once the top1-2 inches of soil is dry. Add a second dose of transplant starting solution to your watering can after 1 week.

Look After Your Transplants

First things first: Sit back, relax, and admire your accomplishment. Thanks to you, those tiny seeds you bought last winter are now full-fledged plants! And you gave them just the right amount of TLC they needed to make it safely outside. Now, your plant parent role transitions more into maintenance mode.

• Prepare for shock. Your plants may experience some level of transplant shock after transplanting. You prepared them the best you could, but it's still a big transition! Transplant shock may involve wilting, yellowing, or curling of leaves. Keep plants well-watered and wait patiently. Within a few days, they should be back to their peppy selves.
• Continue to watch the weather. If temps suddenly dip, cover your plants with a large cloth—a bed sheet, drop cloth, or tarp will work—until the threat of damaging cold has passed. Support the covering with stakes to keep it from actually touching the plants.
• Water and feed. And of course, continue watering your plant babies and providing proper nutrition to help them reach their maximum potential. About a month after planting, start feeding plants an all-purpose plant food such as Miracle-Gro® Water Soluble All Purpose Plant Food, which feeds plants instantly.

Your little seedlings have come a long way—and so have you. Later this summer, you can enjoy the fruits of your labor (pun totally intended) and even try your hand at succession planting for more homegrown goodness. For now, congratulate yourself on a successful seedling transplant!