How to Harden Off Seedlings

By eHow Home & Garden Editor

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For seedlings whose lives began on a sunny windowsill, the vegetable patch is no bed of roses. Before they can handle the wind, rain and strong sun of the great outdoors, tender young plants need a period of gradual adjustment. The simple but crucial process of acclimating seedlings to life in the garden is called hardening off.

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Instructions

Difficulty: Easy

Things You’ll Need:

Lattice Panels
Coaster Wagons Or Tea Trolleys
Cold Frames/greenhouses
Watering Cans

Step1

Begin hardening off your seedlings about a week before their transplant date. (Check the seed packet for the estimated date in your area; it varies depending on the variety of plant.) Keep the seedlings well watered throughout the process.

Step2

Set the containers (whether flats or individual pots) in a sheltered, shady spot outdoors. A covered porch is an ideal starter spot, so is a table or bench under a leafy tree. Bring the plants back inside at night, and bring them in at any time of day if the weather turns cold, windy or rainy.

Step3

Expose the plants gradually to more sun. After two or three days, you can safely keep them in the sun for half a day, then return them to the shade. By the end of the week they'll be tough enough to soak up the rays all day.

Step4

Transplant the seedlings to the garden on an overcast day to ease the shock of transition from pot to ground. If a light mist is falling, so much the better.

Tips & Warnings

At the beginning of hardening-off week, arrange your containers on a rolling tea cart or a child's coaster wagon. Then simply roll your plants back and forth for the twice-daily commute between indoors and out.
If you're away from home during the day, or if you simply don't want to bother ferrying your plants around, consider investing in a cold frame, which is a simple box with a glass or plastic door that opens and closes. Set your seedlings into it and open the door a little farther each day, closing it each night. If the weather is sunny, shade the glass with a piece of lattice for the first few days.
The hardening-off process is identical for vegetables, flowers and herbs, both annuals and perennials.
Even if the weather is unseasonably warm, bring the seedlings indoors at night. Strong winds or heavy rains will topple their lightweight pots and likely damage tender stems and roots.
Avoid setting pots or flats directly on the ground; your young plants could fall prey to snails, slugs or other predatory critters.