Hardening Off

If you’re new to gardening, you might have heard the term “hardening off.” As a new plant parent, generally the first thing you are anxious to do when you bring your babies home, is to plant them right away to show them off. However, depending on where you live and when you bring them home, particularly if it’s in early spring, you’ll need to harden them off before you get ready to plant.

Hardening off is an old fashioned term that refers to helping greenhouse grown plants acclimate to the outdoor environment before planting in order to help them transition successfully. By gradually exposing tender plants to sun, wind, and changing temperatures, it will help the cuticles and stems thicken so that the plant loses less water once transplanted. Remember, most greenhouse grown seedlings have been in a stable, consistent environment their entire lives and throwing them out into the garden and skipping this step will be a shock to them. Sometimes the garden center will have done this for you by placing their plants outdoors on benches before offering them for sale but if you’ve started your own seeds, this is a step you must take. Hardening off should be done over a period of one to two weeks before you wish to plant.

Begin the process by placing your seedlings outdoors in a sheltered spot for an hour or so on the first day. Choose a day when the temperatures are warm- generally above 50 degrees. Be sure to give them a good drink before putting them outside so that they don’t dry out if it gets windy as it frequently does in our area. It’s fine to leave them in a cluster – that will help protect them against wind and keeps them from the chance of blowing over.

Exposing young seedlings to direct sun and full wind too quickly can scorch their leaves so what you are trying to do is build up a tolerance to the elements. Do this by gradually increasing the amount of time you have them outdoors as well as the amount of sunlight you’ll be giving them each day. The key here is to increase the exposure in steps. After a couple of days in one spot that may have shade or dappled sunlight, move them to a brighter location. Leave them in that spot for an hour or so each day, then increase the amount of time they are there over the next few days. Then move them to a brighter spot. Leave them there for an hour or so each day, then increase the amount of time in that spot and so on.

In order to be successful in your hardening off efforts, be sure they are sheltered from pests and critters that might find your tender young plants delicious. Just because they haven’t been planted yet does not mean that rabbits, deer, birds and other critters won’t find them.

The purpose in hardening off is to give you stronger, more resilient plants that will be productive throughout the growing season. Be sure not to rush this process, especially if you live in a part of our area that is susceptible to cold nighttime temperatures. The last thing you’ll want is to rush the process in order to get them planted quickly only to find they struggle from being set out into the elements too soon.