Have you been growing some plants in your house but now want to transplant them into outdoor pots? Don’t overlook the process of hardening them off if you want to continue to see them blooming. In this post, we tell you how to harden off your plants and what can happen if you don’t.
What Does Harden Off Mean?
The term hardening off may be associated with softening water, but among farmers it has a completely different meaning. Hardening off in the nursery is all about getting plants used to the outdoor climate. The plants that need acclimatizing have been grown indoors, whether in windows or under grow lights—those sown outdoors automatically become accustomed to the outdoors from the start. The temperature outside is often referred to as the main thing plants need to adapt to, but the light is just as important, if not more so in some cases.
Difference Between Indoors and Outdoors
Starting life indoors is often very beneficial for many plants. Some grow with a bright window as a light source, while others have plant lighting available. Regardless, the light indoors is incredibly different compared to the sun’s rays outside. Thus, despite having absorbed sunlight throughout their small lives, window-grown plants are still not adapted to the bright light of the ‘real’ sun.
Indoors, life is warm and cozy, usually with a constant temperature. Outdoors, the plant needs to cope with temperature fluctuations. In spring, day and night, temperatures can differ quite a bit. In addition, it is pretty rare for there to be wind indoors, but outdoors there may be occasional gusts of wind depending on how sheltered the plant site is.
How Do You Proceed?
A normal hardening off lasts about a week. This means that you first carry out the hardening off, and then you plant/place the plant where it will live during its outdoor life. There are several ways to harden off. None is better than another. You just have to try it out.
Here are a few ways:
Place the plants in a spot in the garden where there is shade throughout the day and bring the plants inside at night. At the end of the week, you can leave the plants out at night in the shade spot, but leave them in the sun during the day.
Put the plants in partial shade for a few hours each day and let them rest the rest of the time indoors. Increase the time in partial shade and then switch to direct sunlight every so often so that the plants are eventually fully acclimatized.
Create a canvas tent in a greenhouse or sheltered area in the garden. Leave the plants under the fibre cloth for a week, and they will be hardened off and ready. You don’t have to carry your plants in and out this way, but you can leave them under the tent all day.
How to Harden Off Plants in the Greenhouse Under Fibre Cloth?
If you have a lot of plants, you can cover the whole greenhouse with a fibre cloth. Usually, we recommend using clothes pegs to attach the fibre cloth to the structure.
What Happens If You Don’t Harden Off?
If you plant out your plants a little too early without hardening off, the temperature, especially at night, can cause the plants to go into shock and die of cold. Cucumbers and broad beans are particularly sensitive to cold temperatures. A sign that the cold has damaged your plants may be that they look droopy and that leaves, and other plant parts have lost their elasticity.
The sun can also do a lot of damage to plants that are not used to it. UV rays can damage plant parts, turning green leaves whitish.
Plants that have never been exposed to the wind before can be badly damaged by a bit of wind and die. Injured plants are challenging to repair. At best, they may survive and at worst, they die.
If you are going to ignore the hardening off and risk some damage to the plants, you might still choose to do it on a few cloudy days, when there is no wind and the risk of frost is minimal. That way, if you’re lucky, you might still get it right.
Have you done the hardening off process before? How did you find it? Share your experience with us in the comment below.