How To Harden Off Seedlings // Northlawn Flower Farm

Hi guys, it's Danielle with North Lawn Flower Farms. Today I want to talk about hardening off seedlings. Hardening off is the process of gradually acclimating plants to the outside so they can get used to sunlight, wind, rain, variances in temperature, and less frequent watering. This hardening off period allows your seedlings to transition from their cozy growing conditions under lights to the normal conditions they will experience outside in the garden. If we don't take time to harden off our seedlings, they can be shocked by the sun's rays, strong winds, and cooler temperatures. Hardening off these seedlings over time gives them the chance to adapt to their environment and toughen up so that they are better equipped to handle the weather outside. You know, sunlight is a lot stronger than grow lights and can burn foliage if the seedlings are placed in the direct sun on the first day. Light breezes can also sap your plant's moisture and cause weak stems to break. Cooler nighttime temperatures may kill a seedling that's not used to it. So whether you grew your own seedlings indoors under lights or if you purchased transplants from a greenhouse, you will need to harden off your seedlings before transplanting them into the garden. So let's talk about how to harden off seedlings. About a week or two before your transplant date, place your plants outside in a protected spot for two hours and then move the plants back inside for the remainder of the day. Each following day, increase the time they spend outside by an additional two hours, giving them a little more sun and a little more wind each day. So on the second day, four hours out and then back inside. On the third day out, six hours outside and then back inside each day, continuing to expose them to a little more sun and a little more wind. Continue this process until they have spent a full 10 hours outside and are now in the full sun. At that point, you can leave them outside overnight, but be sure to keep an eye on the weather during the hardening off period. Significant temperature drops and strong winds can damage seedlings. Most trays will need additional water during the hardening off period because sunlight and winds can deplete their moisture. During the hardening period, do not allow plants to experience temperatures lower than 45 degrees Fahrenheit. I like to put mine under our covered porch for the first few days and then gradually move them out to experience full sun and wind. After your seedlings are hardened off, they're ready to be transplanted into their permanent location in the garden. Choose an overcast day and transplant them in the late afternoon or evening to give your plants time to adjust without the additional challenge of the sun. Water the seedlings well after planting and enjoy their blooms in the days to come.