In today's video.
We are going to talk about a piece of gardening terminology that you probably
heard 1,000,001 times,
but you really might not know exactly what it needs and that is plant hardiness
zones.
Kevin Espiritu here from Epic Gardening where it's my goal to help you grow a
Plant hardiness zones are sort of the throw away answer the quick answer that
you'll give someone whenever they have a planting question in the garden.
You know someone might come to me with this beautiful seed potato here and they
might say, Hey Kevin, I live in Georgia. When do I plant this potato?
Because I don't live in Georgia, I might say, Hey John,
go ahead and figure out your growing zone,
your plant hardiness zone and then look up a chart and it'll tell you when to
plant that potato and that's an adequate answer.
But plant hardiness zones while helpful,
really do miss a lot of the equation when it comes to gardening and growing your
own food. That's why in this video we're going to go over number one,
how they came to be. The origin story, if you will, of plant hardiness zones.
Number two and what they mean,
what does it actually mean to be a zone five or zone seven right?
And then finally at the end of the video number three,
which is really the most important piece, is how to think beyond the zone.
Think more holistically about your growing space and what that means for what
you're going to plant, when you're going to plant it,
and how you're going to care for it over the course of your garden.
So without further ado, smash that light button for 20 years of good harvests,
blessed to you by yours truly, Kevin Espiritu from Epic Gardening.
And let's go ahead and get into the video. The first thing to understand,
which is of course the most important is what actually is a plant hardiness zone
and what does it mean? So the USDA,
US Department of Agriculture developed it in 1960 and they took 50 to a hundred
years of weather data and said, okay, now that we have this data,
let's split the whole country up.
I believe it was in zones one through 10 at the time. It's now since expanded,
but what those zones correspond to is the average annual minimum temperature in
increments of 10 degrees Fahrenheit with one being the coldest.
So as you move up zone one, two three, four,
five you get a warmer average annual minimum temperature.
So for me here in San Diego in Zone 10 I'm in zone 10b but we're going to get to
that "b" in a second.
I believe that my average annual minimum is either 40 degrees or 45 degrees
Fahrenheit,
which means I actually don't have a freeze in my zone and we're going to get to
what that means in a second as well. Now this has been updated over time.
There was a large 1990 update of the hardiness zones and then there's been
another update I believe in 2006 and then the National Arbor Day Foundation came
out with their own map that kind of artificially inflated because they used just
data from the 1980s and 1990s and so that's why there's a lot of confusion,
but that's really not even the real reason there's a lot of confusion.
The real reason there's a lot of confusion is because like I said,
what hardiness zones measure and correspond to is the average annual minimum
temperature and that's really about it.
They do take into account some micro-climate things,
but for the most part that's what they're telling and so all that's telling you
is how cold it's going to get in your region on average.
Thus kind of it tells you the beginning and ends of your season.
So for example, if you live in zone 10b, which again, that's where I live,
then I just don't have an end to my season because it never gets to a cold
enough level that it kills my plants. Whereas if you're in zone five, six,
seven you're going to have a bookend.
It's a bookend to your season and basically let's go ahead and do this.
If I'm in zone 10b let's just say I'm like this,
there's no true end to the season and as you go zone nine, eight, seven, six,
five, four, three, two,
one the space between my hands is the ability for you to grow plants.
It shrinks as it gets colder because many plants just can't survive in blinding
cold. So what about the 10a to 10b, the zone 7a the zone 7b?
Well that was another update that the USDA did that basically split each zone in
half and instead of 10 degree increments,
it was now five degree increments.
So let's say a zone 10a has an average annual minimum of 40 degrees,
well then a 10b is going to be a 45 and so it's just adding more granularity to
the whole measurement system.
So that's all that hardiness zones really tell you. Number one,
they tell you on average, how cold is it going to get for the entire year?
What's the coldest temperature is going to get for you? Number two,
based on that, when does your season start and end?
And that allows you to figure out a rough estimate of when to start planting,
when to start your seeds indoors,
when to start pulling things out of the ground, all of that stuff.
But let's talk about now what it doesn't tell you the most important thing the
hardiness zones don't tell you is the opposite side of the equation.
How hot on average does it get in your area? For example, I'm in 10b.
It doesn't get too much hotter on average then maybe I would say 90 to 95
degrees,
but some of my friends out in Florida who are also in zone 10b because our
minimum temperature is the same. It gets way hotter there. Not to mention,
the other thing that doesn't tell you is humidity.
It's way more humid out in Florida than it is here in San Diego.
We're in more of a classic Mediterranean climate,
but out in Florida it's still a zone 10b and so if you're only thinking with
hardiness zones, you're going to plant everything on the exact same schedule.
Whether you're in San Diego or you're in Florida and you're not going to have a
good result. On top of that,
it does not tell you average rainfall doesn't tell you the average amount of
drought days. It doesn't tell you the soil quality.
It doesn't tell you all sorts of things like that that really expand your
thinking and your holistic planning as a gardener so you know what to put in the
ground and where it's going to succeed.
So how do we evolve ourselves past the idea of simply thinking about our
hardiness zone, and that's where the idea of micro-climates comes into play.
Microclimates could be something as small as a shaded spot of your garden
because you have a large tree,
a large sort of white painted reflective fence that's going to throw heat back
onto where it's reflecting.
Or it could even be someone who lives in a valley versus a hill in the exact
same planting zone.
So they might still be a zone 10 but someone's living in the valley has colder
mornings, colder evenings, colder nights,
and someone up on the hill is going to have more wind,
they're going to have more blinding heat because it's heating up sooner in the
day. And so these two people are in the exact same zone,
but they must consider both what they plant when they plant and all of that
slightly differently. Now let's shrink it down to just your yard.
Let's say you're someone who really likes tropical fruits,
but you just struggle to grow them because maybe you're in a zone seven which is
sort of on the cusp. Well,
my friend David The Good over at survival gardening has this idea of pushing the
zone. He actually has a book about it and that's the idea of saying, okay,
let me craft,
let me create a microclimate that will support that plant.
So let's say I'm trying to grow that tropical and I need to push that zone about
maybe one,
I need to go from a seven to an eight and all he's going to do in that
situation, which is a fantastic tip, and there's many ways to do this,
is plant it next to a south southern exposed wall,
maybe three, four feet off.
You're going to get a radiant heat that's maybe five to 10 degrees, which voila,
pushes you up either five or 10 degrees in your zone,
which is either a half or a full zone.
And so that's kind of how you start to think about this.
That's why in my recent video on shady gardens,
that's a different zone technically than the planting zone that I currently live
in, my shaded garden,
we might as well just take off one full zone if you have half shade throughout
the day,
and so these are the things that I encourage you to think about when you're
starting your garden to really go deeper than just the surface level knowledge
and go into that.
Why is everything the way that it is and how do I optimize my garden knowing
that? I know we got pretty nerdy in today's video.
I think it's an important topic,
so much so that it's one of the main focuses of the beginning of my book Field
Guide to Urban Gardening. Now this book,
it's designed to take you from a total new,
you don't know anything about gardening,
which is basically how I started gardening to someone who can competently grow
in a variety of different methods. I have six different methods in the book,
including beginners getting started section Green Thumb Basics and a
troubleshooting. But in the middle of that book, you've got raised bed gardens,
container gardens, indoor edible gardening,
balconies and rooftops growing vertically and hydroponics all in here,
including an entire section on voila, the plant hardiness zones.
So if you want to grab it, I highly encourage you to do so.
It's on Amazon or you can get signed copies from my store. But until next time,
thanks so much for watching, guys. Stay tuned.
There's a lot more coming on this channel, and good luck.
Good luck in the garden and keep on growing.