How To Harden Off Hot Pepper Plants

We’ve all felt that shock of stepping out from a warm house into freezing air. Well, plants feel it too! After germinating chilli seeds and allowing the seedlings a little time to develop in a safe, controlled environment, there comes a time when we may want to move them outdoors, where they will develop into profit-yielding adult plants.

However, to just do this in one moment is dangerous, and can be fatal for your little chilli seedlings. Therefore, we must harden them off so that they become robust and resilient to whatever the elements may throw at them.

What is hardening off?

Hardening off (also known as acclimating) is a method used to move a plant from one environment to another, without subjecting it to dangerous amounts of shock—transplant shock. For instance, once chilli plants are well into the seedling stage, many growers will move them from their perfectly managed indoor environment to the great outdoors.

But doing this in one fell swoop could shock them so much that they die, or become stunted and weak. In order to mitigate damage, growers must gradually increase the amount of time plants spend in their new environment, and decrease the time spent in their old one. In this way, the hardening off process helps plants adapt from one environment to another.

Ever notice how herbs bought in the supermarket wilt and die almost as soon as they enter your home? That’s because they can’t deal with the sudden change of environment. If you could acclimate them, you’d soon have a healthy herb garden!

Why is hardening off important?

The hardening off process is important because:

• It helps plants adapt to new environments
• Avoids transplant shock
• Improves final quality of harvest
• Allows plants to be overwintered
• Helps strengthen branches and stems

How to harden off chilli plants

Hardening off chilli plants is an easy process, and absolutely worthwhile. A little effort and care will reward you tenfold in the long run.

When to harden off hot pepper plants?

There are a few factors that will help you determine when to begin the hardening off process. First, come up with an ideal transplanting date. Hardening off in the lead-up to this point is crucial—anything else would be basically pointless.

But you also have to take your cues from the environment. It’s ill-advised to harden off if temperatures are below 7°C; perfect would be anything above 13°C. So if the winter is clinging on and temperatures are staying low, maybe hold off a little. Seedlings reared in propagation chambers will not take kindly to a frost!

So check the weather, and if it’s hospitable, begin hardening off around 14 days before you would ideally transplant them permanently.

Here are a few other indicators that it’s time to begin hardening off:

• Plants are around 8 weeks old
• They are at least 10cm tall
• They have a few sets of true leaves

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How long does hardening off take?

On average, hardening off takes between 7–10 days. However, do not be belligerent in forcing your plants to acclimate! If they begin to wilt, then they’re not having a good time. In this case, bring your plants back inside until they have fully recovered, then begin hardening them off again from scratch. So in total, hardening off could take a few weeks if it doesn’t work out the first time.

Hardening off hot peppers: two-step guide

Hardening of chilli plants only really involves two distinct steps. The first takes place over a week indoors; the second involves taking them out into the world.

Step 1: Pre-hardening your plants

This first step is very gentle and gradual. You can begin this once your plants have one set of true leaves. Using a fan, subject your seedlings to 15 minutes of “wind” on day one. For the next week, increase this by 15 minutes a day.

At first, this is all you need to do. It will help to strengthen the stems and branches of your plants. Otherwise, if you just put them outside, a fairly benign wind could be enough to blow them over and kill them.

Step 2: Hardening them off

To initiate the actual hardening off process, take your plants outside for only one hour, in the shade, and then bring them back inside.

Each day after, increase this by one hour per day. Also, increase the amount of direct sunlight they receive, as this could shock them too. How long you continue this process is not an exact science. Between 7 and 10 days should be enough. Around day 7, if they appear totally healthy, try leaving them in their new environment for a whole day and night, and see how they fare.

If they appear well and healthy after this, then they’re all done, and they can officially be transplanted to their outdoor homes!

If at any point during this step the weather turns very bad, keep them indoors and continue once it’s passed.

Hardening off top tips

As well as following the above steps, there are some further tips and precautions that will increase the likelihood of successfully hardening off your hot pepper plants.

• Water adequately, but not too much. While they need to be hydrated to develop, excess moisture and humidity will increase the shock of cold weather.

• If you see buds growing on your seedlings, you can pinch these off to redirect the plant’s energy back to toughening up, rather than growing flowers.

• Plants that have been overwintered and are going back outdoors will thank you for hardening them off again. However, there’s no need to use a fan, and you can expect them to be significantly hardier than seedlings.

Will hot peppers survive outdoors without hardening off?

Maybe—but the chances are slim, and the costs are high. Putting your chilli seedlings outdoors straight from propagation is a sure way to kill them off. Even if it doesn’t kill them, it could seriously stunt their growth and lead to poor yields and low resistance to pests.

Considering all you need to do is move them outdoors a few times, hardening your pepper plants off is certainly recommended. Moreover, if you’re getting into cultivating any kind of plant, learning these skills is not only important to becoming highly skilled, but highly enjoyable too.

Max Sargent

Max has been writing for over a decade, and has come into cannabis and psychedelic journalism in the last few years. Writing for companies such as Zamnesia, Royal Queen Seeds, Cannaconnection, Gorilla Seeds, MushMagic and more, he has experience in a broad spectrum of the industry.

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