You’ve started all these little seeds and now they are flourishing plants. It’s time to get them in the garden. But there is one thing you need to do first. Here is how to harden off plants so they will transition to your garden easily and stay alive!
I can’t even tell you how many people have come to me and say “all my young plants look great but as soon as I plant them in the ground they all die.”
I usually respond with “did you harden them off?”
It seems you can find all kinds of videos and posts on how to start seeds but there is one important step people are forgetting to share about.
How to harden off your plants so they don’t get transplant shock.
You don’t want to go through all the hard work of starting seeds only for all your tender plants to die when they get in the outside elements!
What’s the purpose of hardening off plants?
The purpose of hardening off your plants is simple. Preparing your roots to be strong so they will survive in all kinds of weather elements.
Up until this point, your young seedlings have flourished into beautiful plants but in a controlled environment. I start all my seeds in the house under grow lights. This means there is no wind, direct sun, or rain hitting my plants. Their roots are pretty weak at this stage.
That is why if you just move them straight into the ground outside, they will likely all die from shock. Their roots are not strong enough to handle all the elements their new environment will throw at them.
I usually start the hardening off process 2 weeks before I want to plant. This gives me plenty of time to get them strong.
Tips for making the hardening-off process easier.
I use to have trays and trays of plants in my house that I would one at a time carry out to a table every day and then back in that evening for weeks. It was a daunting task… every once in a while I would snag an unsuspecting helper just walking by to grab a tray so I didn’t have to make as many trips.
But most of the time it was me.
This year I did a few things to make my life a whole lot easier!
Separate your plants into groups.
In years past I would harden off plants all at the same time. If you are growing a big garden like I am, this is a lot of work. So many trays of plants that need to go in and out.
This year I decided to work smarter and not harder. I separated my plants into two groups. I did brassicas, melons, and squashes in the first group and tomatoes and peppers in the second. This also gave my pepper and tomato plants a little more time in the house and the risk of any chilly nights out of the way. They are much more sensitive.
I knew I needed to get all my brassicas in the ground first, so they were the first group to harden off. The others I left in my house until their turn. This was much more manageable for me.
Make sure to set your groups according to your growing zone and what you need to get out first. You really only need 2 weeks in between each group, so plan accordingly.
A helpful tip: your cold weather crops should be your first group!
Use a wagon to transport.
This year I took our portable wagon and put aluminum trays at the bottom. I then moved all my plants into the trays and rolled it in and out of the shop every day. When I was ready to plant, I just simply rolled it to the garden.
Once I had my groups lined out, I put the first group in the wagon and left the other group in the house. After I had successfully hardened off my first group, I planted them and brought the second group out to the wagon to start the process over.
It worked beautifully!
Watch the weather forecast.
There is absolutely nothing more frustrating then to put your little tender seedlings outside to start the process, only to get a heavy rain or strong winds and it wipes them all out.
Been there. It’s not fun or pretty.
You can’t predict it all but make sure before you even begin to start the hardening process that you are watching the weather. This will give you an idea of when to start. Of course during the whole process I do continue to watch and if we are going to have a bad weather day, I simply just don’t roll the wagon out that day. They will be fine for a day in the shop or garage.
Ok, so let’s harden off plants so you can get them into your garden and have a great growing season! This is a simple process.
On this day it is kind of crucial to the success of your plant. Remember they have only ever been in a controlled environment. So you don’t want to go too quickly for their first time.
It is best to do it on a cloudy day but if you are getting full sunny days, just find a shady spot. Make sure you are only starting this process when your danger of frost is over and about 7-14 days before you are ready to put them into the ground.
You will want to bring your plants outside, into a protected area, for about an hour. Then bring them back inside.
Make sure the wind is light on this day and there is no risk for a storm coming in. You want to ease them into the natural weather elements slowly.
The next day you will want to again watch the weather conditions so you don’t have super high winds or rain. Move your plants outside to a shaded location and let them sit out for about an hour to an hour and a half.
Then bring them back inside. I don’t start this process until there is no longer a risk for freeze, so I just move my plants to the wagon and bring them in and out of the shop. They are no longer inside my house and it makes it so much easier.
During these couple days you will be increasing the amount of time the plants spend outside. Gradually increase the time each of these days by about 30 minutes to an hour, until you are up to a large chunk of time. During these gradual increases, you do not need to keep them in a shady spot the whole time, they can have more sun exposure.
Go ahead and give them some sun and some shade.
Your plants should be spending most of their days outside at this point and only going in for the cool nights.
They should be getting acclimated to all the weather. Light breezes and some light rain shouldn’t shock your plants and they should be almost ready for transplant.
They do not need to be in a sheltered spot or even a shady spot at this point, they can be in the bright sunshine! Your plants will be developing strong root systems and can handle a lot more.
This isn’t really a necessary step and I don’t always do it, sometimes I just leave them in the same spot I had been the whole time.
However, it’s a good idea to place your plants in the garden spot that they will be for the season. You won’t be putting them in the ground yet but this is where they will be once they are in the ground.
I do this because this is going to be their new home for the length of their life. This will be the amount of direct sunshine, wind, rain etc. so before you even disrupt their roots and transplant them into the ground, they are getting used to all the elements.
The length of time to harden off plants depends on your weather and how well your plants are responding. You can speed this process up just a little bit but I would be cautious not to go too fast. It’s always better to go too long then too quick.
Now you are ready to transplant your plants into the ground!
When should I harden off plants?
You will want to look at the last frost date for your area. Then you will want to see what your planting and when they need to get in the ground based on your last frost date.
When you know that information, you will want to then count back 14 days before you would want to transplant them into the ground.
This will give you an estimated time to start hardening off your plants.
Now of course weather will always play a factor in this, so just make sure you are not being too firm on the start time and really watching when it is best to harden off plants for the garden.
The first week is always the most important so make sure you are setting your plants up for success! Continue to give your plants a good amount of water while they are hardening off. With them getting sunlight now, you may notice your soil drys quicker so adjust your watering accordingly.
Following this schedule you should have happy thriving new transplants ready for the garden in 2 weeks. Happy gardening friends!