Cold Tolerance: Garden Plants; Apparently 16 Degrees F is OK

A frequent question we receive is about cold tolerance.  In this post, I'll document two freezing episodes in Portland Oregon in Dec. 2016 with garden plants. 

Potted Plants: Dec. 8 2016.  Temp. +28dF with light snow approximately 0.25 inches.  Note the drooping stems and wilted leaves.  These two were potted in the early summer of 2016 at Frog Eyes Wasabi Farm and then brought to Frog Eyes HQ in Portland Oregon in about late September 2016.

 

Potted Plants: Dec. 12 2016.  Temp. +45dF.  Snow melted within 24 hours.  Note the erect stems and flat leaves.  Some of the slug work / damage was present prior to the snow.  It's unknown how much was existing.  But, I'd imagine the slugs were hungry after one day of snow.  These plants are brassicas; slugs and aphids are common pests. 

Barrel Plants (barrel #2) Dec. 8 2016.  Temp. +28dF with light snow approximately 0.25 inches.  Plants covered by snow and all stems are low and nearly flat.  

Barrel Plants (barrel #2) Dec. 12 2016.  Same time as above potted plants. Note the erect stems and flat leaves.  Note the lesser about of slug work / damage.  Elevating the plants off the ground helps reduce pest damage (from slugs at least).

Potted Plants Jan. 2 2017.  This photo taken during a period of low temperatures at 16-20 degrees Fahrenheit (-9 to -6C).  The duration was approximately 5 days, with the high temperatures below 32dF (0dC).  The center plant was wrapped / covered in typical bubble wrap to determine if any difference is noted between the uncovered and covered plants. 

 

Potted Plants Jan 11 2017.  During a rare Portland snowstorm approximately 5 inches of snow.  Temperatures won't reach above freezing for about 48 hours with a low temperature to the low 20's Fahrenheit.  I haven't unwrapped the center plant yet.  It will warm up tomorrow and I'll do so.

Jan. 25 2017: They seem to have all survived!  The small one on the left was turned over and fell out of the pot.  I was at the farm and didn't re-plant it for a few days, at least one of which had a night that dropped below freezing with exposed roots.  They may not be totally happy, but they seem to have survived and are making a go at it.  Go little wasabi plants go!  The one that was wrapped, the middle one seems to be the happiest with greener leaves.  But, both the larger potent plants are, just this week, producing flower buds!  This plant amazes me at every turn.

New flower buds on the right.  I'm sorry they are blurry. 

Feb. 25 2017: All three potted plants survived.  They are all flowering.

Barrel #2 plants on Jan. 2 2016.  These were left uncovered as an experiment to determine if any difference is observed between the potted and barrel plants and the uncovered and covered potted plants. 

These temperatures, and particularly the duration are quite outside the typical wasabi preference (and frankly outside of mine as well).  It will be interesting to observe the recovery process.

Barrel #2 with a snow blanket.  Jan. 11 2017.

 

Jan. 25 2017.  Barrel #2.  All of the plants seem to have survived.  They even are producing small shoots already, just one week after the freezing temperatures stopped.    

Jan. 25 2017.  Barrel #2.  All of the plants seem to have survived.  They even are producing small shoots already, just one week after the freezing temperatures stopped.  

 

 

Showing new shoots from the apical meristem on Jan. 25 2016 from a Barrel #2 plant.


 

Barrel #2 also survived.  The perimiter plants at the 1 and 2:00 position sustained some cold damage, but they are returning. 

Posted on December 11, 2016 .