So, you want to grow your own food? Bold! You buy the plants you want to grow, make room for them in your garden, and start the transplant process.
That’s all nice and dandy, but before you do that, have you considered that your plant may not be ready to live outdoors? Now you’re wondering: “How do I make it ready?”
That’s what I’m here for. In this post, I’ll show you how to prime plants for spring and fall to ensure they can withstand outdoor weather.
Let’s get right to it!
What Does Hardening Off Mean?
Hardening off refers to preparing your seedlings to live outdoors without catching potential diseases.
You see, young plants that you buy from garden centers are usually quite delicate. You can’t wake up one day and transfer them outdoors out of the blue.
They’re not used to the extreme outdoor weather at that stage so it’ll only stunt their growth and damage their leaves.
How to Harden Off Seedlings
Seedlings usually require a long time to harden off as they’re the most fragile and immature versions of plants.
Here’s how to harden off seedlings:
1 – Expose Your Seedlings to the Outdoors Gradually
The most effective way to prepare your plants for outdoor weather is gradually.
Start by placing your seedlings outdoors for one hour. Avoid locations with direct sunlight and target days where the temperature is over 45℉.
When you take the seedlings inside, don’t put them somewhere cool. Leave them at any warm location in your house.
After a few days, you can increase the exposure period by an hour or two depending on what you see fit. Don’t take your seedlings out on windy days to avoid potential damage.
2 – Increase Sun Exposure
Now that your seedlings can withstand a few hours outdoors, it’s time to transfer them from a shaded area to a spot that gets indirect sunlight.
After three or four days, you can expose them to direct sunlight.
I know the process is tedious, but you don’t want to rush it. If you expose your seedlings to direct sunlight too early, you’ll risk burning their leaves.
3 – Leave Your Seedlings Outdoors Overnight
At this point, your seedlings should be durable enough to withstand prolonged sun exposure.
So, you can leave them outdoors overnight. That said, you should only take this step if the weather is warm day and night.
4 – Plant Your Seedlings
There you go! Your seedlings are ready to face the outside world with its extreme temperature, wind, and storms. All that’s left is to plant it in whatever location you think is best.
Pro Tip: If you’re planting several seedlings simultaneously, keep some space between each one. Otherwise, they’ll fight for water/nutrients and some of them won’t grow properly.
Once you plant the seedlings, water them to minimize the transplant shock.
How to Harden off Seedlings With a Shade Cloth
I know some people don’t have enough time to keep monitoring the seedlings and moving them outdoors and indoors every few hours.
What then? Should you just give up on the whole endeavor? Of course not! There’s always a way to harden off your seedlings without constant monitoring.
How? Shade cloth!
Take your seedlings outdoors and cover them with a 70% UV protection shade cloth. That should offer them the same exposure levels an indoor environment with grow lights does. So you won’t have to worry about potential burns.
After a few days, replace that cloth with a 60% one, then 50%, then 40%—you get the idea. Of course, you don’t have to go down 10% each time. You can go from 60% to 40%. Just make sure not to go overboard with it.
I wouldn’t recommend switching from 70% to 30% as that would leave the foliage vulnerable to sunburns.
While this method doesn’t require as much monitoring as the previous one, that doesn’t mean you shouldn’t give the seedlings any attention. After all, you need to watch for signs of sunburn to act quickly once they occur.
How to Deal With Frost
The obvious answer is to bring the seedlings inside until the frost passes. Here’s the catch: After it passes, you can’t just pick up where you left off, as the cycle has been disrupted.
For example, if you had been covering the seedlings with a 40% shade cloth before the frost, you would need to go back to the 50-60% cloth you had before that.
Final Thoughts
Now you know how to prime plants for spring and fall. That wasn’t so hard, right? Sure, it requires close monitoring, but that’s what caring for plants is all about.
Just go through the hardening process gradually, bring your plants inside during frosts, and plant them when they’re ready. Et voila!
Growing up with a mom who filled her home (inside and out) with all sorts of plants, Lisa got her start in gardening at a young age. Living now on her own with a home and yard full of plants (including an indoor greenhouse), she shares all the gardening tips she’s gained over the years.