If you have read one of our pepper growing guides, you know that we always start our seeds indoors. This means that, for the first several weeks of a pepper plant’s life, it is living inside.
At some point, we need to allow the sun to take over the job of our grow lights. This means moving the pepper plants outdoors, into the elements. This process is known as ‘hardening off’ the plants, and must be done gradually to avoid stressing them.
In this article, we will share our method for hardening off pepper plants properly. We’ll cover when to start the process, how to gradually increase sun exposure, tips to keep in mind, and some methods for in-ground plants. Let’s get started!
What Is Hardening Off?
Many gardeners start their pepper plants indoors to extend the growing season and get healthy harvests. After several weeks of growth inside, the plants will of course need to move to the outdoors to mature and bear fruit.
However, indoor climates are very different from the outdoors. We keep the temperatures constant, the wind at bay, and we use grow lights. Here are a few things that will be new to plants when they move outside:
- Temperature fluctuation
- Direct sunlight exposure
- Wild animals
Since the plants will need to adjust to deal with all of these factors, we must slowly transition our peppers to the elements. This process can take 2-4 weeks depending on each plant’s final planting location.
In our growing guides, we always recommend exposing your indoor pepper plants to some of these factors when possible. One method we use is an oscillating fan to mimic wind. This helps build a stronger stem while the plants are young.
Another method to train young pepper plants for the outdoors is to crack a window at night. This will allow some cooler air to reach your indoor plants and expose them to colder temperatures early on, better preparing them for natural swings in temperatures outdoors. Just be sure to stay above 55°F (13°C).
When to Move Pepper Plants Outdoors
So, when should you start the process of hardening off pepper plants? This will depend on two things: outdoor temperatures and the proximity to your transplanting date.
Generally speaking, start hardening off pepper plants about 2-4 weeks prior to moving the plants outdoors permanently. This gives them enough time to gradually adjust to the outdoors until the plants are fully acclimated.
There is no strict schedule for moving the plants outside, but we do have some guidelines to help ensure your plants adjust properly.
Tips for Hardening Off Peppers
Before we get into the steps for how to harden off your plants, I’d like to share some important tips that you should know about. Each of these were learned through trial and error, and knowing them now will save you the headaches!
- Start in the shade. For the first few days that your plants spend outdoors, choose a shaded area (or an overcast day). The plants will not tolerate much, if any direct sunlight. If you live in a location that doesn’t get much overcast, start in a shady spot in the morning or afternoon for the first 2-3 days.
- Avoid windy days early on. In addition to avoiding direct sunlight early on, you should avoid windy days, too. Your young pepper plants will be relatively weak coming from the indoors. Simply check the weather for any strong winds and work around it.
- Expose young seedlings to a breeze indoors. As I said before, running a gentle fan breeze indoors can help prepare the plants for normal outdoor winds. Start this as soon as the seedlings sprout and rotate the trays to keep things even.
- Don’t leave young plants on the ground outdoors. Young, tender pepper plants (and other veggies) are a tasty treat for some common wild animals. Rabbits and mice especially love young foliage, and they will make quick work of your plants. So, during hardening off, keep the plants elevated and, ideally, in your line of sight to avoid disaster!
- Use shade cloth for in-ground plants. If you are taking your plants to a full-sun location to be planted in the ground, hardening off can be tricky. If you don’t have a full-sun location in which to gradually transition the plants, moving to the open garden bed can be a shock to the plants. I recommend using floating row cover to partially shade the plants. Start with a couple of layers, and remove them one at a time over the course of several days. This effectively decreases sun exposure until the plants have adjusted to full-sun conditions.
- Watch the temperatures. High temperatures can be overwhelming to a young plant. Peppers should be fine with daytime temperatures between 65-90°F and nighttime temperatures above 55°F. Any colder, and they should spend the day/night indoors.
Note: If you are using a balcony for hardening off, be careful. Micro-climates can form and cause very high local temperatures, even if the ambient temperature outdoors are normal. In short, use a thermometer!
With these critical tips in mind, you should be ready to begin transitioning your pepper plants to the outdoors.
How To Harden Off Pepper Plants (Steps)
Keep in mind that these steps are just a loose guideline that can be followed. However, depending on your climate, the temperatures, wind, and precipitation can make an impact, so use your best judgement and stay vigilant.
How to Harden Off Pepper Plants
- Choose a suitable first day.
We generally begin the hardening off process 2-4 weeks prior to moving our peppers outside permanently. This date range will depend on your specific climate. Whatever container the peppers are in will do, but we like to keep ours in large 1020 trays for convenience.
- Start in the shade.
Avoid direct sunlight for the first few days of hardening off. Choose a shaded spot and avoid windy days. These factors will stress the plants more than is necessary. After about 2 hours in the shade, bring the plants back inside until the next day.
- Gradually increase outdoors time and sun exposure.
After 3 or so days of shade, the plants should get some sunlight. We usually start with just 10-20 minutes of sun exposure before returning the plants to the shade. The plants will adjust quickly, and each day you can increase sunlight exposure by another 10-20 minutes. Watch for drooping leaves and sunscald, and adjust sun time accordingly.
- Monitor the temperatures.
During this process, temperatures will be key. Indoors, the plants had even temperatures, but outside, they fluctuate. Use a simple thermometer to monitor the area and avoid temperatures above 95°F or below 55°F.
- Leave plants out overnight when above 55°F.
Once the plants have been hardening off for around 2 weeks, they should be prepared for an overnight stay.
Tip: Keep the plants elevated and protected from rabbits and other hungry herbivores that may like to feast on your plants!
- Move the plants outside permanently.
After 2-4 weeks, your pepper plants should be transitioned to the outdoor elements and ready to keep growing in their new homes.
During the hardening off process, we are still fertilizing and transplanting at the appropriate times. The plants can be hardened off in whatever container you have them in. The point is to adjust the plants to the outdoor climate in the meantime.
I hope this article helps you properly move your peppers outside for the growing season. If you have any additional questions about hardening off pepper plants, let us know in the comments.