Making ‘Hardening Off’ Not So Hard

April 18, 2018

Transitioning tender seedlings to the outdoors isn’t always easy.
Here’s the best way to harden off plants successfully


Hardening off.  I was so baffled by this term when I first started gardening, almost 15 years ago now.  Books and blogs alike will tell you, rather blithely, to “harden off” your indoor-sown seedlings and transplants before planting them in the garden.  But what the heck does that mean?  Why should you do it?  And how do you do it properly?

You might be interested: We Sow the Seeds

Why Harden Off Your Plants?

It’s kind of a weird term, but to harden off your plants doesn’t mean to make them physically hard.  It means to make them hardy.  Impervious to the elements.

It is, at it’s most basic, simply preparing seedlings for life in the great outdoors.

Sown inside, seedlings are used to warm, even temperatures and diffused and constant light.  The air is usually calm, and the water lukewarm.  Outside, in contrast, can be harsh and mercurial.  Rain, wind, hail, cold, heat, sun and shade can all affect a garden in the space of a single and normal spring day.  A tender baby plant, grown and cared for indoors, will probably wilt and die if planted outside with no previous acclimation.  They just don’t have the resistance necessary to deal with all the environmental changes and the shock of exposure.

The best way to help those seedlings you’ve labored over thrive outside, is to harden them off.  Luckily, hardening off is a really easy process once you understand what to do.

Get more information on growing seeds here: 6 Tips to Grow Healthy Seedlings

how to harden off seedlings

How to Harden Off Seedlings

Some sources will advise you to go through really elaborate hardening off schedules.  Like, an hour in dappled sunlight on a 50 degree day, gradually (over the course of a week) increasing time spent outside to the full day.  Still in dappled sun.  Then, and only then, can you start to harden off your plants in full sunlight for another week.

Um, ain’t nobody got time for that.

I agree that hardening off is important.  But it can also be done so much more quickly and easily.  Typically, I harden off my plants in five or six days.  And I don’t spend any time at all worrying about dappled light.

Here’s my hardening off schedule:

  • Day One:  Place plants outside in the morning, and bring the plants back inside after a few hours, or earlier if they’re starting to wilt.
  • Days Two-Three:  Repeat the process, leaving them outside longer each day
  • Days Four-Five:  Assuming the weather is mild and no frosts are forecast, let the plants stay outside all night
  • Day Six:  Transplant them!

I would like to stress that I am in a very temperate zone 8, and my last frost date has already come and gone.  If you are in a colder part of the world, you may very well choose to take more time to acclimate your seedlings to the outdoors.  There is absolutely nothing wrong with that, and I urge you to always use your best judgement.

You might like: What to Sow and Grow in April

Tips to Make Hardening Off a Success

The one thing I have learned over the years is that hardening off is more of an art form than a science.  There is no real “right ” way to do it; success has everything to do with your individual plant and weather conditions.  That said, there are definitely some tips that will help your plants thrive outside, no matter where you are or how you do it!

  • Try to start the process on an overcast or mild day
  • Put your plants in a shady spot on the first day (or in dappled light even – I don’t judge!)
  • Keep them somewhere safe from animals
  • Avoid hot temperatures and bright sunlight
  • Keep your plants watered
  • Shelter your seedlings from strong winds if possible
  • Shoot to transplant your seedlings on an overcast or mild day
  • After you’ve planted, you may still need to provide protection (like cloches or row cover) if there is a spate of bad weather

Find your last frost date: USDA Hardiness Zones

Hardening off your plants is really not as intense or hard as you might think it is, but there’s no getting around it – it can be time consuming.  However, this is not a step you want to skip!  Your plants will thank you!

Do you have questions or other tips about hardening off your seedlings?  Email me, visit my contact page, or comment below! 


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how to harden off seedlings


  • Spring Lake Homestead

    April 18, 2018 at 4:31 pm

    I’m so bad at hardening off. I always forget to do it, and then my plants struggle for weeks because of it, and in the end, I would have been better off just starting my seeds outdoors. I need to do better this year!

  • The EcoFeminist

    April 18, 2018 at 5:48 pm

    Yeah I was totally intimidated the first time I started seeds and tried hardening off the seedlings and instructions were so nuts on how to do it… The worst part for me is remembering to bring things in at night 😆

    1. lacey

      April 22, 2018 at 1:59 pm

      It took me a long time to get the hang of it, too. It helps me to just put them right outside my back door, and then I can’t (usually) forget them outside!

  • Liz

    April 26, 2018 at 7:28 pm

    Definitely my least favorite part of growing seeds – I am so horrible at remembering to bring them in at the end of the day! I’m in zone 7 and I do just about the same as you, but usually take about two weeks to do it, with most of the second week is them just living outside around the clock. Thanks for sharing on Homestead Blog Hop!

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