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Day 7: Hardening Off Seedlings

Day 7: Hardening Off Seedlings

Mary Smith |

Welcome to Day 7 of our series Grow Your Own Food in 100 days or Less at Mary's Heirloom Seeds!

These are the extra Heirloom Corn seedlings that didn't make it into our Mother's Day Garden

So far we have planted heirloom seeds in our raised bed, planned out our garden, watered our seeds and applied cayenne pepper to deter gophers.  If you start seeds indoors and plan to transplant seedling into the garden, it is important to harden off your seedlings.

No video today but we have pictures!

What does it mean to "Harden Off" seedlings?
From our article Hardening Off Seedlings before Transplanting

Hardening off gradually exposes the tender plants to wind, sun and rain and toughens them up by thickening the cuticle on the leaves so that the leaves lose less water. This helps prevent transplant shock; seedlings that languish, become stunted or die from sudden changes in temperature.

Hardening off times depend on the type of plants you are growing and the temperature and temperature fluctuations. So be flexible when hardening off your seedlings and be prepared to whisk them indoors if there's a late freeze and snow.

Jarrhadale Pumpkin Seedlings happily growing outside

If you're growing seedlings indoors, they might have been pampered all winter/spring.  Aside from the random cat attack or possibly too much watering, they have been relatively safe compared to the dangers that await them in the great outdoors.


This was taken at one of our school garden volunteer days
How to Harden Off Seedlings
Start by putting your seedlings outside 7-10 days prior to transplanting.  In the beginning, give them shelter and plenty of water.  You can strengthen stem of indoor seedling by adding a fan while they're indoor.  This will help to prepare them for windy days outside.

Start by leaving them outdoors for 3 - 4 hours and gradually increase the time spent outside by 1 - 2 hours per day.  Bring the plants back indoors, or somewhere warm like a heated garage or porch, each night.
If temperatures remain warm both day and night,  the plants should be able to handle the sun all day and stay out at night after about 7 days, Keep an eye out that the soil doesn't dry in their small pots and bake the plants if the weather should suddenly turn warmer.
If you've planted in Cococut Coir pellets, pay extra attention to moisture levels.  Coconut coir can dry out faster and might need to be watered daily when outdoors.
If you opt to gradually expose your plants to longer periods of time outdoors, the moving in and out process can be made easier by putting your plants on a wagon or wheelbarrow and simply wheel them into the garage for the night.
Hardening off is an important step is you choose to grow seedlings indoors.  It's a bit of work but can be worth it if you want to get a head start on planting if you live in cool/cold climates.
All of my seedling this year are grown outside on a covered patio.  That means I don't have to harden them off before transplanting. Unfortunately, we lost a few to earwigs.  Fortunately, I planned a head and planted more than I thought I would need so there are extras to make up for any eaten seedlings.

Thank you for joining us for another day of Grow Your Own Food in 100 Days or Less.  If you have additional questions please send an email to mary@marysheirloomseeds.com

Happy Planting!


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