How To Harden Off Pepper Plants

Pepper plants are outdoor plants, however, before it’s ready for the outdoor weather, it is usually planted indoors or in a nursery until it’s ready for transplanting. To make it ready for transplanting, you must ensure it adapts to outdoor environmental conditions. This process is known as hardening off.

Hardening off pepper plants involves exposing the seedlings to outdoor conditions until they survive. 

So, do you want to learn how to harden off pepper plants? To explain it in easy terms involves exposing the seedlings outdoors for one hour on the first day and returning them indoors. On the second day, expose it for 2 hours and move it back indoors. Continue the process to the next day while adding the time it stays outdoors until it stays outdoors for 12 hours without withering from exposure. 

Read through to the end to find the process of hardening off pepper plant seedlings.

What Is Hardening Off?

Hardening off is the process of making a plant adapt to the transition from a protected indoor environment to outdoor conditions. For a transplant to be successful, the plant has to undergo hardening. 

Most gardeners start growing pepper seeds in a nursery or a greenhouse since they can’t survive outdoors when young. However, as they grow into seedlings, it comes to a point when they are ready to be moved to a garden with favorable conditions for them to grow. 

So, why is it important to harden off pepper plant seedlings? 

You first need to understand that seeds are grown indoors because you can control the indoor climates to suit the plant’s needs. For instance, you must keep the temperatures constant using a thermometer to avoid cold or hot temperatures. Also, you need a grow light for about 14 hours a day to give the seeds enough light. 

Yet, all that is not possible outdoors. You can’t control temperatures or the amount of sunshine the plant receives daily. 

So, to remove the plant from a controlled environment to an uncontrolled environment, you must harden it to ensure it can survive in harsh weather conditions. Some of these harsh conditions include: 

  • Wind
  • Sunshine 
  • Rain 
  • Temperature fluctuation
  • Direct sunlight exposure 
  • Wild animals. 

When is the best time to start hardening off pepper plants?

Many factors come in place to help you decide the best time to start hardening off. Here are things you should consider; 

  • Start hardening off two to four weeks before the transplanting date. 
  • Always ensure the last frost date has passed before you start hardening them off. 
  • Ensure that during that period, the night temperatures are above 55 degrees Fahrenheit. 
  • Make sure that the plants are 8 weeks or older to survive outdoors. 
  • The plant should start setting a few true leaves. 
  • The plant should be about 4 inches tall. 

You should note that all these factors can happen all at once, and in some cases, it can be a single factor that guides you for the best time to harden off pepper plant seedlings. The only thing you have to avoid is hardening them early. 

How to harden off pepper plants.

Hardening doesn’t have a set deadline; the plant can be ready between two and four weeks. Also, the steps we are about to outline below are loose guidelines you should follow. Use your best judgment depending on weather conditions such as temperatures, wind, and precipitation in your area. 

Here is a step-by-step process of hardening off pepper seedlings.

  • Start them indoors

First, start the process indoors by subjecting the plant to the wind. Run a small fan near your plant for about 15 minutes on the first day. Keep the breeze moderate, so the plant doesn’t move back and forth. 

  • Increase exposure time

For the rest of the days that week, increase the time the fan blows around the plant by 15 minutes each day. For example, on the second day, it receives 30 minutes of wind, and on the third day, it receives 45 minutes. 

Blowing wind to a plant is done indoors because outdoor winds can break your plant if it has a weak stem. 

  • Move them outdoors into a shade.

Now that you are done with indoor hardening, it’s time to move outdoors. 

Place the plant outdoors in a shady spot, leave it there for 15 minutes, and then move it back indoors. If the weather is bad, remove it immediately. 

  • Increase the amount of time in a shade.

Continue placing it in a shade as you increase the time it stays outdoors by 15 minutes each day. 

  • Expose them to the sun.

After 3 or so days, start placing it in an area with exposure to sunlight. Increase the sun time each day to ensure it adjusts correctly. 

When placing it in the sun, check for drooping leaves and sun scald and adjust the time of the sun.  

  • Leave the outdoors at night.

After about 2 weeks, you can leave the plant outdoors at night when the temperatures are above 55 degrees F. Leave them out for a week, and they will be ready for transplanting.

When the plants are ready to survive outdoors, you can move them outdoors to their permanent home. 

What happens if you don’t harden off pepper plant seedlings

Sometimes people prefer to move the plants from a nursery directly into the garden without hardening off. For some, it’s possible if the conditions are favorable for the plant. 

However, it’s a different case if the outdoor temperatures are unfavorable. Most transplanted plants go into shock. It’s known as transplant shock. 

Transplant shock occurs when a plant undergoes a sudden change and cannot develop natural defenses to protect itself. If it can’t protect itself from the conditions, it goes into shock and becomes weak. 

Weak plants can die from cold, pests, diseases, and heat. 

So, it’s best to take those 2 weeks to harden off seedlings to avoid losing them to shock. 


It may not be a rule to harden off seedlings before transplanting, but it’s an important step to consider for your plants to survive and grow into healthy fruits. Follow the guideline provided to help you start hardening off pepper plant seedlings. 

Also, don’t forget to water and fertilize your seedling during this process. The plant continues to grow regardless of the conditions; it’s trying to adapt. 

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