How to Harden Off Your Flowers the Easy Way

The practically effortless method you’ll love

How do you harden off your flowers? Do you carry them out onto the porch or back deck, only to bring them all back in a few hours later? If you’re like me, your flowers kind of take over the house for a few weeks during this acclimation process. They’re lined up against the living room window or sprawled across the kitchen table during this annual rite of Spring.

My Mom taught me how to harden off my flowers by leaving them outside for a few hours, but always bringing them back inside the house. It’s actually the traditional method. You leave them out a little longer each day, gradually increasing the exposure to the sun and wind until they’re thoroughly “hardened off”. (that applies to vegetables, too!)

Protect your investment: harden off your flowers

It’s not just about getting plants used to the outside temperature. That’s only part of it. Believe it or not, it’s exposure to the intense rays of the sun that’s most harmful to plants fresh home from the nursery. It’s tempting to set your trays and hanging baskets out on a bright sunny day thinking it’s good for them.

But if your flowers are not properly hardened off, they could be seriously sunburned. They might not die, but a plant in a weakened condition could take the entire summer to fully recover. A sunburned plant will be hard pressed to produce a flower and that’s a serious set-back for us in Alaska where our summers are so short. The flowers you bring home from the greenhouse need to get accustomed to the sun. That procedure is commonly called “hardening off.”

Yet, I hated all that laborious in and out, in and out. Every day. In and out, in and out. Trays of lobelia, petunias, and geraniums commandeering prime real estate in the small duplex apartment where I lived at the time. I was so glad when it was finally over and I could hang my baskets and plant my pots. One day, the City’s local garden expert introduced us to an entirely different method.

What’s to love about this method?

• Your kitchen table won’t be held hostage for two weeks
• You do not have to shuffle flowers in and out every day
• No propping open the door letting mosquitoes in and pets out!
• It’s way less labor intensive

Ready for some relief? Read on!

Here’s the easy way to harden off your flowers

As a garden hobbiest, I just couldn’t help but share this great tip with you; especially this time of the year. It’s the method I’ve used for more than twenty years now and can testify that it not only works, but also is so much easier!

IMPORTANT: Do not start this process until over night temperatures have been consistently 42-45 degrees at your house. After danger of frost is well passed.

• Place your plants against the side of the house for protection. Preferably a shady or mostly shady location.
• Use a light piece of plywood board to block plants from sun, wind. You can also use styrofoam board or whatever’s on hand that works.

• Leave the plants outdoors in their location, covered by the board for one full week. Check on plants regularly and water as needed.
• After the first initial week, adjust the board so plants begin to receive some periods of sun and breeze.
• If your plants have been on the shady side of the house, now is the time to move them to a sunnier side. Set the board aside so that plants are exposed to a few hours of sun, then replace the board. Remove the board for longer periods of of time each day to increase exposure to sun and wind. Note: This is the same process as using the traditional method to harden off your flowers, except that instead of carrying them in and out, you simply move the board.

At the end of two weeks, your flowers and veggies will be ready to plant in beds and pots. However, if your flowers haven’t seen the sun very much because the weather has been cloudy, they’ll still need to have some adjustment before being fully exposed to the sun.

Use your wagon

Here’s another smart suggestion from a neighbor. She keeps all her nursery plants in the garage. She puts them into a wagon and simply pulls the wagon in and out of the garage. How clever is that? She’ll let them sit out in the sun for awhile and then pull the wagon load back into the shade or into the garage.

Conclusion

There are several tried and true methods to harden off your greenhouse flowers. Whether you try this alternative or decide to stick with the traditional one, the important thing is to do it! Don’t get in a hurry and rush your flowers or you may risk damaging them. Please talk to your favorite local greenhouse folks to learn more about hardening off your flowers and veggies and remind your friends, too. Happy Gardening!

Related Post you might find helpful

Got aphids? Greenhouses try hard to control insects but sometimes microscopic eggs don’t hatch until after your flowers are home. Other times, aphids come from surrounding trees or shrubs. All it takes is a good breeze to blow them down into your garden. Here’s a link to my home remedy that really works!

A Cheap and Effective Way to Kill Aphids