Hardening Off Tender Plants

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Most experienced gardeners recommend “hardening off” transplants to friends and family. Unfortunately, the response is often a long blank stare.

The hardening off process is very important if you start your own seeds under lights or purchase young tender transplants. The process is simple, but does require some time and a willingness to get your plants off to the best start. Suddenly moving a tender seedling from a sheltered environment in the home, greenhouse, or store can result in shock. The plant can wilt, struggle, or even die before it can get acclimated to the new environment.

Help your plants adapt to the new environment slowly. Rather than suddenly moving seedlings to the garden, give them time to adjust to the changing temperatures, the increase in sunlight, and the addition of wind. The key is the gradual transition of the plants to the new environment. This will reduce the shock they experience and prepare them for more consistent growth. The process is simple, but does require some time and attention on your part for a week or two.

Plants are living things and hopefully ready to grow and produce new foliage, flowers, and possibly fruit. Here are some tips to help avoid plant shock and possibly death.

  • A week or so prior to moving your seedlings to the garden, move them outside on a warm day. Place them in partial shade where they are protected from the wind. For the first couple of days, only leave them outside for a few hours. Over time, increase the amount of time they spend outside, as well as how much sun they receive.
  • Bring your plants back indoors overnight or during colder temps (such as frost warnings). Even cold-hardy plants can suffer damage if exposed to freezing temps before hardening properly.
  • Another aspect of hardening includes cutting back on water and fertilizer. Of course, do not allow your plants to wilt, but definitely increase the time between waterings so their growth will slow while transitioning.
  • When your plants have spent the majority of their day in the sun and can tolerate less water, they are probably ready for their new home in your prepared garden spot.

This may sound like a lot of work, especially if you have a large number of seedlings. Do this process could save you some dollars is fewer lost plants and an increase in production. Consider hardening off your plants by using a large rolling container, such as a flat garden cart. This will allow you to pull plants in and out of the house or garage with less time and trouble.