Hardening Off

 This morning we had a Freeze.  A Frost occurs when the air temperature is 32F-36F (0C-2C).  A Freeze is anything below 32F.  This morning it was around 28F (-2C).  The 10 day forecast has warmer night time temperatures so it is time to start moving my more tender Pepper, Tomato and Coleus plants out into the cold frame.

Hardening off is the process of getting plants grown indoors under a grow light accustomed to cooler temperatures, wind stress and most importantly sun.  I keep the workshop under 70F (21C) so they are used to more mild temperatures, but sudden extreme heat would affect them.  I keep fans on my seedlings so actual wind is not such a big deal.  Sunburn is the most damaging problem.  

The accepted program is to bring seedlings out for an hour each day, increasing by an hour each day until they can be out all day.  Then they can be transplanted  That process takes at least a week. You already know how "lazy" I am about hardening off the Cole Crops.  I have a shortcut for hardening off the rest of my plants too.  I am blessed with this cold frame.  The polycarbonate panels transmit only 80% of sunlight preventing sunburn.  If I bring the plants out to the cold frame for a week, they can then go from the cold frame directly out to the garden without sunburning.

I have had Marigolds, Zinnias and Dahlias out here for a week.  They have weathered several frosts out here because the cold frame generally stays about 10 degrees warmer than the night time temperature.  Now that we have little risk of frost for the next 10 days they can go out in the garden.  I am not going to jump the gun and plant them out yet.  I moved them out to the raised bed garden, which is warmer anyway because of all of the gravel, where they will be protected from critters.  They can get used to overhead watering, and more wind and direct sun before they get transplanted.  I remember one year I planted out four dozen Marigolds, and we got a frost a few days later.  I had to cover 48 individual plants.  With pots mostly.  With a rock on top of each pot to keep it from blowing away.  I'm not doing that again.  Last year I had most of my vegetables either in the ground or potted up into larger containers, when we got  days of cold rain.  I'm not doing that again either.

White Marigolds and Profusion Zinnias

I am really looking forward to planting these out.  Usually when I finally get out to the local greenhouses to pick up what I have not grown, I am tempted to buy more big, beautiful annuals.  Not this year.  My annuals are looking amazing.

Dahlias from seeds (left) and a tray of mail order Perennials

There is no sense in taking unnecessary risks.  I pinned some frost cloth over them.  This cloth blocks 50% of sunlight.  If I keep them covered all day that would actually move them backwards in the hardening off process.  I will just put it on in the evenings.

Now I have room to move more tender annuals from the grow lights to the cold frame.  My Tomatoes are coming out and my Coleus cuttings.  Coleus is very sensitive to cold.  I didn't want to knowingly expose them to frost.  

These El Brighto Coleus are from four plants I bought mail order back in 2024.  These are a Proven Winners variety that are impossible to find locally. I took cuttings and over wintered them from 2024 to 2025.  Then last fall I took more cuttings.  I lose a few cuttings each winter, but I have enough for what I want to do with these and this fall I will probably take cuttings again.  I was planning to order in a few more of their varieties this year, but I don't really have any other spots that I want to use Coleus right now.  I just can't lose my stock, so I have a spot where they will work.

Today I also started putting out my Dahlia tubers. Its a big project and I am easing myself into it. We are going to have a couple of days of rain, but I'll get back to that project later this week.