How to Harden off Seedlings

First Step for all new plants

Remember these are your babies and they need to be treated very delicately before being put into your garden and the new unprotected world from their life indoors.  They will not survive if you go from indoors to the harsh world outside without hardening them off.

It is a good idea to look at the weather forecast for the next 10 days to make sure that it is not going to be too cold or too hot for your hardening-off time and once you plant them in the garden.

I also recommend a condensed version of the hardening off for plants you purchase since your garden may differ from the garden center where they have lived.

Below we’ll detail How to Harden off Seedlings with a day-by-day process to help you be successful.


How to Harden off seedlings and plants

No matter where your plant came from it is best to start by hardening off the plant 7 to 14 days before planting them.

Day 1 when the temperature is above 50 degrees Fahrenheit, place the plant outside in a shaded and protected area for one hour to start acclimating the plant to its new environment.  Be sure the area for the plants outdoors is safe from animals and pests, each day return to an indoor area.

Day 2 repeat the process and add an hour a day.

Day 3 and 4 place the plant in an area that has dappled sunlight but not if it is very hot and not if it is windy.

Day 5-7 you can place seedlings/plants in the direct morning sun for 5-6 hours.  The plants are ready to plant outdoors or you can continue this last step for several more days before planting.  Make sure night-time temperatures are not going to drop too low to harm the plants.

Tips on How to Harden off Seedlings

Brush the plants lightly a couple of times each day to emulate the wind blowing to help acclimate them.  Place the plants on a wagon to make it easier to move the plants back and forth.

Be sure to water the plants before putting them out to make sure they stay moist and they may need a little extra water during the day as you move them into more sunlight.  Make sure the night temperature and daytime temperatures are not too low or too hot which can damage your plants.


When you are ready to plant your seedlings and new vegetable plants you will need to prepare the soil before planting.  I will outline the best way to prepare the soil in later articles to provide the best environment for your plants.  Be sure night-time temperatures are not going to be too cold for your vegetable starts.

If it is still cool at night you will need to protect them to insulate the plants from the cold.

If you get plants out to early it will stunt the plants, so best to make sure night temperatures are warm enough so that the vegetable plants thrive.

Here are some examples of the types of plant protection for cool temperatures that you can purchase to get your plants outdoors early in the season

Now that you know How to Harden off Seedlings you can get your garden off to a good start with the healthiest plants with the best success rate once you have planted them.

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