Last Expected Frost Date

Trying to figure out when the first expected frost in your area will be can be frustrating.  The problem is that no one knows for sure.  Everyone is guessing - some using historical weather data, others not.  A good bit of the information that I found is old, whether it be taped to a desk at the Master Gardener's office or online in a 1988 NOAA report.  Another source I have for this information is Gardening in the Carolinas by Bob Polumski.  I'm going to lay out some of this information and let's see if we can reach a consensus.

MG Office - Average First and Last Frost Dates
Charleston Airport     November 20th     March 15th

NOAA - 50% Frost Chance Table
50% chance of Frost on or after the spring date indicated
50% chance of frost on or before the fall date indicated
Charleston AP            November 12th     March 18th

NOAA - 10% Frost Chance Table
10% chance of Frost on or after the spring date indicated
10% chance of frost on or before the fall date indicated
Charleston AP            October 30th         April 6th

Gardening in the Carolinas by Bob Polomski
average date of first fall freeze 11/21
average date of last spring freeze 3/11 or 3/16

What does all of this mean?  Let's start with the MG office information.  First of all, I don't know the source.  I believe it to have been reliable when it was taped to the desk, but I can't say when that was, but the dates are in the ballpark.  The info in the Polomski book is a little dated, but it's also a little hard to interpret.  Like the MG office, it's an average, but it's also a couple of graphics of NC and SC with wavy lines.  Once again, these first and last average frost dates are in the ballpark - see for yourself.

When I first started writing this, I wanted a clear answer - the NOAA information seemed too vague.  But now that I've reached this part of the article, it makes the most sense.  No one is going to know for sure when it will freeze, until it does, but the table gives a good estimate.  On November 12th, you should be planning on it to freeze, if it hasn't done so already.  The same thing goes in the spring - by April 6th there is very little chance that it will freeze again.  Like I've said before, none of this is exact, but it's the best we've got - unless you want to go by the farmer's almanac.

First Expected Frost Date

Trying to figure out when the first expected frost in your area will be can be frustrating.  The problem is that no one knows for sure.  Everyone is guessing - some using historical weather data, others not.  A good bit of the information that I found is old, whether it be taped to a desk at the Master Gardener's office or online in a 1988 NOAA report.  Another source I have for this information is Gardening in the Carolinas by Bob Polumski.  I'm going to lay out some of this information and let's see if we can reach a consensus.

MG Office - Average First and Last Frost Dates
Charleston Airport     November 20th     March 15th

NOAA - 50% Frost Chance Table
50% chance of Frost on or after the spring date indicated
50% chance of frost on or before the fall date indicated
Charleston AP            November 12th     March 18th

NOAA - 10% Frost Chance Table
10% chance of Frost on or after the spring date indicated
10% chance of frost on or before the fall date indicated
Charleston AP            October 30th         April 6th

Gardening in the Carolinas by Bob Polomski
average date of first fall freeze 11/21
average date of last spring freeze 3/11 or 3/16

What does all of this mean?  Let's start with the MG office information.  First of all, I don't know the source.  I believe it to have been reliable when it was taped to the desk, but I can't say when that was, but the dates are in the ballpark.  The info in the Polomski book is a little dated, but it's also a little hard to interpret.  Like the MG office, it's an average, but it's also a couple of graphics of NC and SC with wavy lines.  Once again, these first and last average frost dates are in the ballpark - see for yourself.

When I first started writing this, I wanted a clear answer - the NOAA information seemed too vague.  But now that I've reached this part of the article, it makes the most sense.  No one is going to know for sure when it will freeze, until it does, but the table gives a good estimate.  On November 12th, you should be planning on it to freeze, if it hasn't done so already.  The same thing goes in the spring - by April 6th there is very little chance that it will freeze again.  Like I've said before, none of this is exact, but it's the best we've got - unless you want to go by the farmer's almanac.

First Frost

I've been wanting to get a new wireless indoor/outdoor thermometer - the one we have doesn't work anymore. I got it for Xmas last year and I'll probably get a new one this year. I've looked at them online and they have ones with up to three remote sensors. I'd like one of those, but I can't justify spending the extra money. Believe it or not, but different areas of the yard can be different climates.

I've had conversations with serious gardening friends and they've told me about different areas of their yards being different temperatures and plants that thrive in the back yard, but not in the front - and I'm starting to believe the same is true about our yard.

I didn't pay much attention to the temperature when I woke up Thursday morning, but it was probably close to freezing. When I got the paper about 5am, there was frost on the ground. It wasn't until I got home from work that I was able to survey the damage the frost might have done. I've got a few tropicals by the pond that I knew wouldn't look good - hidden ginger, banana plant, etc - so I wasn't concerned about that. The vegetable garden looked fine - even the garlic, which is supposed to die back in the winter. It wasn't until I got to the front yard I notice that our asiatic(?) lilies showed some signs of frost damage - that's really the only thing I saw. I don't have multiple thermometers in the yard yet, but from what I've seen, the front yard is going to be colder than the back. The back has the pond and is a lot more sheltered with the house, garage, trees, etc. The front yard is mostly wide open - including the fact that the canopy of oaks that line our street, ends with our yard - the north side of our yard, where all our plantings are right now, is treeless and and exposed.

I wasn't expecting the frost, so I didn't protect the house plants I still have outside. To my surprise, everything is doing fine, including the night-blooming cereus, which I think might be trying to bloom. We've got near-freezing weather forecast for the weekend and maybe beyond - I just need to remember to bring in a few plants and everything will be fine.