How to Transition Your Seedlings to the Great Outdoors

Now that spring is knocking on the door, it’s time to transplant our seedlings into the garden!

 

 

Ah, the great outdoors, the place beneath the sky where the wind blows, the birds sing, and the sun shines—how good it is to be there! Inside, our seedlings can only grow so high. But when we bring them outside, they can root down, drink in the rain, and grow into a mature garden. If you’re wondering how to successfully transition your seedlings, here is a detailed guide.

 

How Do You Transition Plants from Inside to Outside? 

Now that spring is knocking on the door, it’s time to transplant our seedlings into the garden. You wouldn’t throw yourself into a month-long camping trip without some prep, right? Likewise, seedlings also need a transition time before they can grow outside. They’ve never experienced the wind, the flux of temperatures, the rain, or the sun. Their skin is quite tender, and they need a time of adjustment (called “hardening off”), so they can acclimatize to their new digs without shock.   

 

How to Harden Off Your Seedlings in Pennsylvania 

Hardening off is not an exact science, but the basic idea is to gradually increase your seedlings’ exposure to the great outdoors over 1-2 weeks until they’re comfortable spending the whole day there. Here are the steps to follow: 

Day 1: Bring seedlings out into the shade for two hours and return them inside.

Day 2: Bring seedlings into the dappled shade for two hours and return them inside.

Day 3: Bring seedlings into the full sun for two hours and return them inside.

Days 4-7: Gradually increase the seedlings’ outdoor exposure to full sun by 1-2 hours each day until they spend 8 hours outside.  

Day 8: Now they are ready to be transplanted in the garden. 

Pro Tip: Remember to keep your seedlings well watered when hardening off because the wind and sun can quickly dry out the soil in small trays! 

 

When Should I Move My Seedlings Outdoors in Glenside, PA?

You don’t have to wait until the last frost date (April 14th in Glenside) for these hardy plants, but hold off on tender warm-season crops until after the risk of frost has passed. Here are some dates to begin your growing season:

 

 

 

How to Transplant Seedlings into the Garden

While it’s tempting to just dig a hole and plant seedlings, following a few key tips will increase your chances of success and reduce the stress on your little plants: 

• Choose an Overcast Day: a cloudy day gives your seedlings a more comfortable transition, rather than transplanting them on a hot, sunny afternoon. 
• Keep Your Seedlings in the Shade: to reduce their stress, it’s always best to keep your seedlings in the shade while preparing the soil and digging the holes. 
• Choose Your Layout: keep in mind the amount of sunlight they’ll receive, the appropriate spacing, and any companion planting strategies to improve your success. 
• Dig Your Hole First: prepare your hole before removing the plug from the tray to minimize the time the roots are exposed to the air. If you have two people, one person can dig the holes, while another transplants behind them. 
• Remove Your Plants from the Trays Gently: the best way is to gently squeeze the outside of each compartment and pop the root plug out of the tray. If that doesn’t work, have a butter knife on hand to ease the process.
• Keep As Much Soil with the Roots as Possible: ideally, keep the whole root and soil plug intact as you transplant it into the new spot. This will prevent the roots from receiving air exposure. 
• Plant at the Appropriate Height: excluding tomatoes, which can be planted lower, make sure you plant each vegetable at the same height as it was in the tray. 

 

• Firm Up and Water In: gently firm the soil around the plant with your hands after transplanting to collapse any air pockets, and give each one a fresh drink of water.
• Mulch Them (Optional): to protect the soil, reduce moisture loss, and add nutrients, you can lay a light layer of grass clippings, straw or salt hay around the plants.   

 

How to Keep Your Transplants Alive 

It happens all too often—we spend six weeks growing our seedlings, giving them a gentle transition into the garden, and wake up the following day only to find our beautiful plants nibbled to the ground. Sometimes mice, rabbits, and deer can’t resist the fresh offering of early spring greens. 

 

To preserve your plants, ensure your garden space is fenced or meshed off against rabbits and deer and away from mouse habitats (chicken wire can come in handy here!) If necessary, plant companion species around your new transplants, like marigolds, allium, catnip, and lavender, to keep rodents away. 

 

The beginning of the growing season is a time to transition seedlings outdoors and when we can finally step outside again. Our imaginations can only grow so high! The great outdoors is the place of growth for us and the plants. If you need more advice on growing seedlings outdoors or supplies to get your season started, feel free to visit our garden center in Glenside, PA!