Are your seedlings ready to make the move? If you want to prevent your seedling from going into shock, you must prepare. Don’t let the time and effort you’ve invested so far all go to waste. Let’s get your seedlings and plantlets ready to pass the threshold from indoors to outdoors. It’s time for hardening.
A new environment
There are 3 elements that will be new to your indoor seedlings; the sun, rain and wind. You need to gradually introduce the outdoor environment. Otherwise, they won’t stand a chance of surviving the move outside.
The sun
The intensity of light and heat coming from the sun can destroy a tray of seedlings. Indoor conditions can’t compare to the amount of energy the sun emits on a clear day.
Some thought should be given on how you’ll protect young seedlings from extreme heat and light. Small hydroponic systems can be built with castors for easy mobility into the shade. Or position your setup under an awning that can open and close.
The rain
There are 2 potential problems that the rain presents. Rain can drown your plants and dilute your nutrients. A line of defense should be in place for when heavy rain is in the forecast. Tarps are useful for this if the weight of the tarp is not placed on your plants.
The wind
Strong winds can snap the stems of your seedlings and plants. It can also cause loose containers that are not anchored to your setup to topple over. You can keep seedlings in a smaller setup that can be moved to a more sheltered area during times of high wind.
You can also strengthen your seedlings while growing them indoors.
Place a small fan directed at your seedlings as soon as their first true leaves develop. Set the fan’s speed at a level that makes your seedlings gently flutter. This not only strengthens your seedlings, it also increases air exchange. A fan will deliver fresh oxygen to the young plants. Additionally, air movement deters any pests from harboring in hidden areas. It also helps prevent fungus from developing.
Hardening off your indoor seedlings
Indoor seedlings need to be gradually introduced to the outdoor environment before they make it their permanent home. If we don’t harden them off, their chance of survival is little to none.
Here is an example of how you can get your seedlings accustomed to the outdoor elements.
The first day:
- 2 hours outside
- choose a shaded area for seedlings, protected from direct sunlight
- a safer alternative is in the evening, as the sun sets
- bring seedlings in for the night
The next 6 days:
- gradually increase the time outside
- gradually increase exposure to direct sunlight
- make note of any stress and watch moisture levels to avoid drying out
The 7th day
- seedling should be ready to spend the night outside (Provided night temperature stays above 10 degrees Celsius.)
- do not transplant on this night
- transplant the following days, preferably on a cloudy day, or in the evening
Helpful tips for your outdoor seedlings
Once you’ve completed the hardening process, there are some extra steps you can take.
- Protect your seedlings from sun scald by placing an upside-down milk crate over them. It will diffuse both light and wind to further protect them.
- Provide additional support for delicate stems with small stakes. You can use popsicle sticks or wooden bbq skewers.
- Extra support can be done by shoring up the base of your seedlings with your growing medium.