How to Harden Off Seedlings
Growing some of your own food is one of the kindest things you can do for the planet. An organic, no-till home garden cuts your food miles, helps limit co2 emissions from the soil, and avoids fossil fuel usage from things like pesticides and fertilizer.
If you’re just starting out however, learning to garden can be a steep learning curve. You might try to get a head start on a short growing season by growing indoors, only to see them die promptly after being put in the garden.
The reason many plants struggle after being put outside is the shock of suddenly changing environments. Plants, unlike humans, were never meant to be moved around. In nature the spot they grow in is the spot they live in their whole lives.
Suddenly being moved, popped in new soil, with new day/night cycles, and new temperature changes are a big shock your plant doesn’t know how to handle.
You can help eliminate this shock by introducing nature to your plants gradually. This is called ‘hardening off’ your plants.
What to do
To harden off your seedlings, you simply need to introduce them to nature more gradually. Take your seedlings out, still in their pots, and let them sit in a protected outdoor location for an hour the first day.
That hour will tell your plant a lot. It will introduce it to wind, the new temperature outside, as well as the heat of the sun. This exposure will send instructions to your seedling to strengthen its root system if it needs to (in order to support itself in a windy area) or to add more ‘sunscreen’ to its leaves.
Bring it in after that hour, and put it out again the next day for two hours. Add an hour each day until it has been a full week. Once your seedlings are outdoors for 7 hours, you can go ahead and plant them. They’ll have had the time to adjust to the new changes in their environment, and it won’t be such a big shock when they are planted.
Protect your Babies
Hardening off is a nice, gradual transition to the outdoor gardening space, but be careful where you put them outside. Too much sun when a plant isn’t used to it can burn their delicate leaves, and putting them down on the ground can put them at risk for animals to knock them over.
The best day for putting your plants out is one that is warmer than 45F, protected from direct sunlight at first, and on a table or something that will keep slugs and other animals out of them.
It’s also important to bring them in from the cold at night, even if it is a frost tolerant plant. You don’t want your plant to get shocked by the sudden change from warm and insulating indoor grow tent to frosty cold night their first day.
Don’t worry about mistakes
If you make a mistake, just continue as normal the next day. Your plants will still benefit from the hardening off process if they miss a day or get left out too long. Introducing your plants to the outdoors gradually will help you have gardening success during the transition process.