Hardening Off Your Seedlings
Moving is one of life’s most stressful events. Imagine how trying it would to move from a
perfect climate where it’s always 70 degrees, calm and sunny, to a harsh and windy climate
where it gets really cold at night and the sun is burning hot during the day.
Put yourself in your seedlings shoes. If you had to move from San Diego to Montana, wouldn’t
you want some time to adjust?
You’ve started your seeds. Kept them hydrated just right. Transplanted them. Maybe fed them a
diluted dish of fertilizer or two. They are tall now.
Your seedlings may look like they are ready to go it on their own in your garden, but be kind,
prepare them for the extremes of your garden with a process called ‘hardening off.’
The author of ‘Grocery Gardening’, Jean Ann Van Krevelen, said you shouldn’t skip the step of
hardening-off your seedlings. Young plants may not make it if planted directly into your garden
with out a transition.
“When seedlings are grown inside in a controlled climate, they don’t have the opportunity to
develop the strength and structure to live out in the elements. They need to get acclimated to
their new home, “ said Van Krevelen.
To harden off your seedlings, gradually introduce them to the outdoors. It helps to store your
seedlings in trays, at this point, to make transporting the plants easier.
“Take your seedlings to a protected location outside for one hour for the first day,” she said,
“Do this each day for a week. Add one hour for each day of the process. By the end of the week,
you’ll be at 7 hours and the plants will be ready to be transplanted,”
While inside, seedling stems haven’t been exposed to winds. Plants, like us, need to start our
workouts and gradually increase the intensity to become strong. So early on in the hardening
off process, provide seedlings shelter.
“Don’t put them in direct sun. Don’t put them in a windy location. Keep in mind, they are just
babies,“ said Van Krevelen.
If you want to help your plants beef-up early, you can add a fan to the area where you are
storing your seedlings. Use the fan to gently move the air. Too much direct breeze from a fan
could dry out the seedlings and do the same damage wind would in the garden.
Gardeners have different approaches to the watering aspect of the hardening off process. Van
Krevelen keeps her seedlings evenly moist from grow light to garden.
“Provide consistent moisture. Seedlings are susceptible to any extreme until they are
established,” she said.
Horticulturalist Erica Shaffer agrees. “Don't send your babies into the big, bad world of your
garden thirsty and hungry,” she said.
Good gardeners aren’t perfect. And the process of hardening off doesn’t have to be executed
perfectly or uniformly to be highly successful. If you forget to take your plants out one
morning before work, just start back up the next day. If the spot you chose for them becomes
too sunny as the day went on, all is not lost. Plants are a forgiving lot and will hang in with
you as long as you give them a little attention.
There is a bit of hassle involved in schlepping the plants outdoors and back in again each day
over a week. But after gently caring for your baby plants for weeks, the added effort is good
insurance that your plants will leave your nest safely and do well in your garden. After all,
don’t you want to shield every thing you love from unnecessary stress?