In this guide, we’ll show you how to get your indoor plants ready for the great outdoors, and some important things you should know before putting them in your vegetable garden.
If you have been following our blog, then you’ll know that we’re big fans of using an AeroGarden to start seeds. With the help of a seed starting kit, we can grow a large number of seedlings all at once, giving the advantage of a headstart in the growing season, leading to bigger plants and a bigger harvest!
But when those baby seedlings get too big for their little cradles, you can’t just stick them outside and expect them to survive! Ironically enough, indoor plants can actually get sunburnt from the outdoor light, and if they aren’t properly prepared, they can be stressed from the shock of leaving home, leading to stunted growth at best, or a dead plant at worst.
To avoid this from happening, we do what’s called “hardening off”. In a nutshell, it involves gradually exposing a plant to outdoor conditions, allowing them to adapt to the change in the environment, and toughens them up, so to speak.
Now, if you are using an AeroGarden to start seeds, the first thing you’ll need to do is to get your seedlings ready for living in soil, as opposed to a hydroponic system. When your seeds have germinated and are showing their first set of true leaves (about 1-3 weeks), you should be ready to transplant them into soil.
We wrote up a guide on transplanting seedlings out of an AeroGarden, so feel free to check it out for all the details.
In essence, you start by transplanting your seedlings into grow pots using a good quality potting soil, keep them moist, and give them about a week to get used to the soil conditions.
As soon as the weather outside is not so frightful (ie: no risk of frost!), you can pretty much get started with hardening off. Otherwise, you can keep your green babies indoors under grow lights or a window sill.
How Long does it take to Harden Off Seedlings?
On average, I find it usually takes up to 2 weeks to fully harden off an indoor plant, depending on what you grow. If those plants have been under some intense grow lights, they might take less time to harden off. For other plants, some can be very sensitive to a change in environment. I’d suggest checking out a growing guide for the specifics on a given plant.
The First Day of Hardening Off
First, we start off by placing the seedlings outside, but in a shady spot where they don’t get full sun. You’ll want to leave them for a few hours unattended before bringing them back inside. I like to do this during the morning or the evening, when the sun is not too bright out.
For the next day, and each day afterwards, we begin to gradually expose them to more and more sunlight. I like to start with about 30 minutes of full sun, but to keep it safe, you can stick the seedlings in partial sun or shade. It’s usually good to put them outside in the morning if you can, that way they will gradually be exposed to the sunlight and change in temperature.
Check for Signs of Overexposure!
But when you bring them indoors, you need to check each seedling to see how they look and feel. If the plant is stressed, it may be wilted or have sunburnt leaves (the leaves will be pale, or start to turn white).
If you are lucky enough to not have any stressed seedlings, you can leave them outside the next day for just a little bit longer. Just remember to check for stress, and keep them out of direct heat if they show any signs. Otherwise for each successive day, you can keep them out a little longer.
During the entire process of hardening off, make sure you keep a close watch on the moisture of the soil; the last thing you want to do is to stick a dry plant outside. I like to give them some water in the morning, that way, they’ll have a fresh supply when the sun starts to hit them with rays. When the plant starts to harden off into the afternoon, I like to check the soil again for moisture; if it’s dry, I’ll add a little more, to avoid wilting.
Once several days have passed, and you have to leave your seedlings out all day long, it is a good idea to check them several times throughout the day, to ensure that they are still looking healthy. Depending on where you live, you may want to make sure that they are kept safe from any critters that might like to snack on tasty plants.
Finally, after about a week or so, and your plants are spending time out all day long, then they should be all set to go into your garden, or wherever you plan on keeping them. Not only are those seedlings tougher as a result, but they may have grown a bit more in the process.
Anyways, this is just about all I have for today. I really hope this hardening off guide has been helpful for you.
Until next time, wherever you live in the world, enjoy life, have fun, and happy homesteading/gardening!