Hardening off Bedding Plants
Hardening off simply means to gradually acclimatize bedding plants from indoor to outdoor temperatures over a period of several days before planting. The result is a “tougher” more hardy plant in the garden.
Plants that have been hardened off are usually sturdier, bushier and better able to withstand all types of weather, then those that have not been through this process.
To harden off your own seedlings, all you need to do is place the pots or packs outdoors in a sunny area at least a week prior to planting. Don’t forget to water everyday, because plants that dry out in the pack usually do not fully recover.
If there is a risk of frost, cover the flats or containers with an old sheet, towel or blanket, a roll or burlap, sheets of newspaper or a cardboard box. Never use plastic, because it has virtually no insulation value.
If bringing the plants indoors overnight is more convenient, then do so, but remember to return them to there sunny location outdoors the next morning, after the temperature has risen above freezing.
After seven to ten days of this treatment, the plants will have hardened off and are ready to be planted into the garden.
- an excerpt from Lois Hole's Bedding Plant Favourites