Hardening Off: Transitioning Seedlings from the House to the Garden

A transition process called “hardening off” eliminates the danger.

AeroGarden Seed Starting Systems help gardeners extend their harvest, use their containers and garden beds more efficiently, and grow more fruits and veggies compared with soil-based seed sowing. But seedlings grown indoors will suffer sunburn and transplant shock if they are planted directly outdoors without preparation. A transition process called “hardening off” eliminates the danger. 

The first step of the transition from an AeroGarden prepares the plant’s root system for life in the garden. While you can harden off in your AeroGarden reservoir bowl, you may have to move them to small pots and soil first if your weather isn't warm enough to allow planting in your garden within a week. Then you'll harden off in those vessels. Transplant young seedlings from your AeroGarden into soil or high quality potting mix like Miracle Gro Potting Mix soon after they grow their first set of true leaves.  Using high quality Miracle Gro Potting Mix will help your plants grow twice as big (vs unfed plants) and feeds for up to 6 months.

If the weather is favorable, the hardening off process may begin right away. Otherwise, wait to harden them off and keep them under bright lights indoors. You can use one of our powerful grow lights if you don't have sunny windows.

It typically takes one to two weeks to properly harden off seedlings that were grown indoors for planting in full sun. Due to the superior quality and intensity of light they've received from the start, AeroGarden seedlings take a week or less. Each kind of plant will respond a bit differently.

Begin by placing the potted seedlings in a bright, shady location outside for a few hours in the early morning or late afternoon. The next day, let them experience dappled sunlight, or a half hour or so of full sun. Each day check for signs of stress, such as whether the plants become wilted or sunburned, or if they appear unaffected. If everything looks good, add more time outdoors and more direct sun exposure each day.

Pay close attention to soil moisture during the hardening off process. Water primarily in the morning. This will ensure they are well hydrated before experiencing the stress of sunlight and wind. Water late in the day to correct or avoid wilting. After a few days, when the plants are staying outside around the clock, be sure to check on them at least twice a day. After the hardening off period, your seedlings are ready to go into the garden!