May 20, 2008 2 min read

Spring is in the air, and many flower and vegetable enthusiasts cannot wait to get their hands — and new plants — in the soil. Here is a proven practice gardeners can add to their regimen to make the gardening experience a more successful one, filled with lots of healthy productive flowers and vegetables.

In the spring, young seedlings should be hardened off before you transplant them into the soil.

Hardening off is an acclimation process of gradually exposing plants grown under protected conditions — such as in a greenhouse, hotbed or gardener’s home — to unprotected outside conditions of full sun, wind and cool nights.

Acclimating plants to the garden environment will prevent damage from sudden changes in light intensity and temperature. Plants taken directly from the house may brown or turn white from exposure to direct sunlight and wind.

Even though the plants may not die, the damage will reduce their vigor, and more time will be needed for the plants to become established and flower.

Begin the hardening-off process at least two weeks before transplanting.

Place seedlings and small plants in a cold frame or sheltered area, and expose them to outdoor conditions for several hours on mild days.

At night, you can also place plants on a sheltered porch, shed or garage area, away from gas and engine exhaust. This protection will safeguard them from cool nighttime temperatures that may damage plants before they are hardened off.

Gradually, over 10 to 14 days, move plants into sunlight for increasing periods of time each day.

Do not put tender seedlings outdoors on windy days or when temperatures are below 45øF (7øC).

Reduce the frequency of watering to prevent lush, weak growth, but do not allow plants to wilt.

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This article was prepared, written and adapted by Christina Yoder Becker, master gardener coordinator for the Penn State Cooperative Extension, Fayette County, from an article from the Department of Horticulture, Penn State College of Agricultural Sciences.

Penn State Cooperative Extension is funded by the U.S. Department of Agriculture and state and county governments.

Local Extension educators and volunteers can be reached at fayettext@psu.edu or by phone at 724-438-0111.