Zone Defiance

Most of our common succulent varieties are recommended for zones 10 and above.  Since we are at zone 9b (Eureka, CA)  we need to plan carefully for the winter months.

Last winter was a particularly bad winter, we had 8 or more subfreezing days (29* or below) at my home in Cutten, just outside of Eureka I had 6 days in a row that were below 29*, my low was 18*. Some areas behind my house didn't defrost for days.   Even with all that I lost very few plants.

This winter, looks like it will be mild according to many weather forecasters, but you should still be ready to protect your plants in case of frost.

Here is some of the things you should do to plan for frosty days:

Placement is everything!!!   Try to get the sun on your plants as early in the morning as possible.  I recommend east or south exposure.  Look for things that might shade your plants in the winter.  North exposures are the worst in the winter!

I have a low fence that shades some parts of my garden when the sun is at a low angle.  I move plants out of these areas that are sensitive for the winter or plan on replacing them in case of extreme frost conditions.

This is my south facing bed as it came out of the winter.  All of these plants were in ground for the deep freeze.  I covered with frost cloth and on the worst of the nights cardboard on top of it.

Plant valuable plants that you can't bear to lose in containers that can be moved inside if the thermometer drops below 30* .   You can move plants in the house or  garage in a hurry.   You can even rip them out of a planting if you can't move the container.  I did this with an Echeveria cante after the first night of the hard freeze we had and it survived.  

I removed a poorly performing rose from this spot by my front door.   This allowed me to move some planters from the north side of my house to the south side.   In the case of a severe frost, the house will help keep the plants warm or I can move them inside. 



This is what frost damage looks like on an Aloe! Sad! 

  This photo was generously sent by a friend in San Diego from last years freeze.   Many plants will not survive damage like this, but you might be surprised.  Don't throw them out right away, just move them into a warm place and let them defrost.

This plant looks like it would be toast, but surprisingly this Echeveria imbricata survived.   Frost hardiness boils down to the way the plant stores water in the cells in the winter.  Know the plants that are more sensitive in your collection and protect them accordingly.  Zone defiance outside usually can be done within two zones using micro-climates and coverings.  

The case for frost cloth! 

1.  It really works!   It gives you 4-6 degrees in protection, which is enough to protect from damage.  Multiple layers are fine and do not weigh down on the plants. 

2.  It can be left on the plant if needed, other materials will damage plants if there is rain in the night before a frost or if you leave it on the plant.  

3.  It is easy to apply, I can cover my whole collection in about 15-20 minutes.  

4.  It is inexpensive, about $0.08 a square foot.  

Here is a pair of shots from the last winter, you can see how the frost does not extend under the frost cloth.  

Do you see the frost line?  This was a pretty frosty morning!   Are you convinced yet?  Keep in mind we are just one zone below the recommended zone for planting.  In lower zones you would have to supplement heat with soil cables, incandescent Christmas lights or  move the plants inside a greenhouse, or even a basement with lights.

My suggestion for frost cloth is that you should cover every night we are forecast to be 36* or below, this will help you get in the habit and then you will not be out there at 11:30 at night covering because the weatherman got it wrong.

I have frost cloth also known as row cover, so just give me a call.  I have plenty, it is $0.50 a foot for a 6 width.

Please let me know if you have any thing to add.  What have you had succeeded with  to prevent frost damage?  What did't work for you?