Hardening off seedlings before transplanting must occur in order for plants to acclimate to the outside temperatures and natural sunlight.
This process is time consuming but it’s often a labor of love. Or at the very least, a necessary evil.
However you feel about hardening off seedlings, it must be done. Best to embrace it and keep your garden growing and thriving!
If you don’t, your plants could shrivel and die, or their leaves might get sunburn. I didn’t know this when I was a first-time gardener.
Now I’m more than a few years in and doing my best to improve each season. And I’m happy to share some tips on how to harden off seedlings so you can transplant everything outside in no time.
Learn how to acclimate plants to outdoors for a successful garden this year!
Hardening Off Definition
Hardening off is the process of acclimating plants and seedlings to the outside climate. Exposing seedlings to new growing conditions enables them to adapt to these settings slowly over time.
After hardening, plants are less likely to go into shock or suffer major issues getting used to the new growing environment.
Advantages of Hardening Off Seedlings
The hardening off process may seem tedious, but try to look at all the positives!
Here are some of the added benefits of hardening off before transplanting:
- Plants Gradually Grow Accustomed to the Outdoors.
- Brighter Sunlight Accelerates Growth.
- Natural Wind Encourages Stronger Stems.
- Soon, Plants Can Thrive Outside!
- Your Family Can Help You, Making this a Memory in the Making!
How to Harden Off Plants before Transplanting
It’s easier than you might expect when hardening off seedlings before transplanting.
You simply need to get into a rhythm and try a few simple tips to add convenience!
- On the first day, put your plants in the shade for one hour.
- For the second day, put your plants in the shade again, this time for two hours.
- Add an hour each day, keeping your plants mostly in the shade at first.
- You can begin to introduce some indirect sunlight a few days to a week into the hardening off process. Just be careful not to overdo it right away.
- Gradually increase the amount of time the plants are in indirect sunlight.
- Slowly introduce direct sunlight, just a little bit at a time at first.
- In 10 days, you may have your plants outside for as many as 10 hours with much of the time in the natural daylight.
- Continue to increase the length of time until you are comfortable leaving your seedlings outside overnight.
(Remember to check the weather forecast carefully!)
- After two weeks, give or take, your plants should be fully ready to transplant. (I’ve heard some can go as quickly as a week, but I like to take my time to make sure the plants are good to go.)
Tips – The Easy Way to Harden off Plants
Try these simple tips to make hardening off seedlings even more convenient.
- Start hardening off seedlings in the shade and then add a little extra sun each day.
- Put your pots in basins and bins to make them easier to tote.
- Use a wagon to cart around your seedlings hardening off between shade and sun, inside and outside.
- Don’t forget to check your plants regularly! Identify sunburn and leaf scorching early so you just lose a few leaves and not the whole plant. Or avoid leaf burns altogether!
- Check the soil moisture. Water as needed. Do not let the plants dry out in their trays in the sun.
- Watch the weather forecast. Avoid major downpours to limit mud and mess coming back into your home.
Final Thoughts: Hardening of Seedlings
The hardening of seedlings takes time but brings many benefits to the plants, namely, getting them transplanted safely and soon.
Your plants will be much happier once they make it through the hardening off phase!
Some plants are more delicate than others. Use care with each type of seedlings you prepare for the big world.
And watch your frost dates and overnight lows!
You can also try these tips for Hardening Off Tomatoes to get your prized crops started off for a happy and healthy future of growing outside.
By the way, if you are new to gardening or could use a little help hardening off seedlings from inside, be sure to check our post, Hardening Off Plants – Don’t Make These 7 Beginner Mistakes.
It gives tips for all the problems I’ve already experienced in my own gardening adventures so hopefully you won’t run into the same issues.
What are your favorite tips for the hardening of seedlings? Do you use any special equipment or techniques not mentioned here?
Please share your favorite tips or any questions you may have in the comments below. We always love hearing from you!
05.10.23 – Updated to freshen up content and added faq, reorganized a bit.