September 9, 2025 • 24 mins
Thinking about building raised garden beds but not sure what materials to use? Today on Just Grow Something we dig into all the options for raised bed construction, from wood, stone, and galvanized steel to creative choices like reclaimed materials, fabric grow bags, and more. We’ll talk about the pros and cons of each, including cost, durability, aesthetics, and safety concerns like chemical leaching or microplastics. You’ll also learn when (and if) you need a bottom layer to block weeds, stop burrowing critters, or protect your soil. Whether you’re a new gardener or looking to upgrade your existing setup, this episode gives you the science-backed insights you need to choose the right raised bed materials for your garden. Let’s dig in!
Perfect for: raised bed gardening, beginner gardeners,vegetable gardening, sustainable gardening, DIY garden beds, pressure-treated wood safety, and backyard food growing.
Save 20% and get Free Shipping on your new planter from PlanterBoxDirect.com! Use code JUSTGROW20 now through October 15th, 2025!
References:
https://extension.umn.edu/planting-and-growing-guides/raised-bed-gardens
Full show notes can be found at https://justgrowsomethingpodcast.com/episode/materials-to-use-for-building-a-new-raised-garden-bed-ep-266
Mark as Played
Transcript
Episode Transcript
Available transcripts are automatically generated. Complete accuracy is not guaranteed.
(00:00):
Last week we talked about how todecide on the correct size of
raised bed construction for yourspecific needs in your garden.
Continuing the series this week,we're talking about the
materials we can use for that construction.
Whether it's reused materials, prefab purchases, or just
(00:20):
leftovers from another project, you really can build a raised
garden bed out of almost anything.
So today I'll just grow something.
We're looking at what to build your raised beds with and
whether or not you need anythingat the bottom to contain the
soil or keep out pests. Gardeners sometimes worry about
(00:40):
chemical leaching from wood, thelongevity of the materials they
use, and how to keep weeds and clears at Bay.
So today we tackle it all. Let's dig in.
Hey, I'm Karen and what started as a small backyard garden 20
years ago turned into a lifelongpassion for growing food.
Now as a market farmer and horticulturist, I want to help
you do the same on this podcast.I am your friend in the garden
(01:04):
teaching evidence based techniques to help.
You grow your favourites. And build confidence in your own
garden space. So grab your garden journal and
a cup of coffee and get ready tojust grow something.
So we definitely have all the fall feels going on here right
now. It has been unusually cool in
the overnights. It has also been much, much
(01:25):
cooler during the daytime. And it just has me like pulling
out the hoodies and pulling out the flannels.
I know we're going to warm up again, you know, this week or
whatever, but it's been kind of nice to feel the fall coming in.
And so it got me thinking about putting some hoodies back into
the shop. So I've still got all the tank
tops and T-shirts and the mouse pads and all kinds of other
(01:47):
stuff in there, but I'm going toprobably go ahead and start
dropping in some of the cooler weather stuff.
So like the long sleeve stuff and the hoodies.
So just growsomething.com, go toshop and you will find all the
options in there. I put some fun stuff in there
earlier in like the late spring,early summer.
I kind of dig the Alexa weed, the garden design and some other
(02:10):
ones. So have some fun checking that
out. I'm definitely going to throw
some hoodies in there too. I have used so many different
types of materials to create raised beds over the years that
I've actually lost track. I haven't even come close to
exhausting all of the options. So scrap wood, obviously.
(02:31):
Prefabricated beds, old metal wash tubs and wash bins, old
leaky stock tanks, giant fabric growing beds.
All of the things I have tried aton of them.
You can use old bricks and stackthem into a bed, concrete
blocks, pavers, you can even usestraw bales or like old logs as
(02:51):
a way to create the perimeter ofthe bed.
And also sometimes you can use those as the planter themselves.
Although that last option acts more like a pot than a large
planter. But it's a pretty cool way to
work with just found materials. The decision for what type of
material you want to use comes down to a couple of things.
How long you want the material to last, what your budget is,
(03:15):
and your aesthetic. Now obviously if you want the
bed to be built once and last for decades, then you're not
going to choose straw bales or old logs that are going to break
down after a really short periodof time.
You might choose reclaimed wood because it's free and you can
just give it a coat of paint, extend its longevity, which is
(03:36):
what I did for many, many years.But eventually those will break
down, too. Those beds are being replaced
with new planter box direct bedsas they sort of fall apart.
And I also scored some very inexpensive fabric beds with
like, pockets that divide them into square foot, you know,
gardening spaces. And I'm using those as temporary
(04:00):
beds this year in some spots where I just needed some extra
plants. Now, I don't think those fabric
beds can stay in place over the winter if I want them to last
very long. So the soil will likely be
removed and I'll put it into my compost pile, and then I'll
store those beds away. But that may be a good option to
see if a particular layout worksfor you or if, like me, you just
(04:22):
needed some temporary extra space.
But I wouldn't leave fabric bedsin place for too long or they
will start to break down. If you're pulling up like old
pavers from a landscape project,you can use those to create a
bed depending on how many you have or if you score some cheap
concrete blocks someone's givingaway and just use that.
But if you have a specific design that you're going for or
(04:45):
you want something that will match the design or colors of
your house, you might need to spend a little bit of money to
get what you want. And often that means the beds
are going to last longer too. Even, you know, combinations of
materials may work in this respect.
So material choices. Let's start with wood.
(05:06):
Wood is the classic choice because it's relatively
inexpensive and it's easy to work with.
So soft woods like pine and fir are affordable, but they
definitely rot faster. Hardwoods like cedar and Redwood
are definitely more durable, butthey are costlier.
And some gardeners use pressure treated wood to extend that bed
(05:29):
life. And this is where we're going to
talk some science. There has been a long standing
adage among gardeners that you should not use pressure treated
wood to build your raised beds because you risk the chemicals
used in that wood, specifically arsenic, leaching into the
(05:51):
garden beds. But let me assure you, for newly
purchased pressure treated lumber this is no longer a
concern. Modern pressure treatment uses a
preservative called micronized Copper Azol, or MCA, and it
contains copper but no arsenic. Research from my alma mater,
(06:11):
Oregon State University, found that this type of lumber
increases soil copper concentration only within about
an inch of the wood and only by about 20 parts per million, and
that no excess copper was found in the vegetables that were
grown in those beds. So this means the risk of copper
uptake is extremely low. The primary concern might be to
(06:35):
direct contact between the gardener and the pressure
treated wood, or through accidentally inhaling or
ingesting large amounts of the soil that might contain some
copper. If this is a concern for you,
wear gloves when you're handlingthe lumber and try not to inhale
disturbed soil or just wear a mask.
Older treated woods are a different story.
(06:57):
Those contain chromated copper arsenate, CCA or creosote or
pentachlorophenol, and those should never be used to create a
raised garden bed. This means you need to know the
source of your pressure treated wood.
So if there is any question, be sure sure you are buying new
(07:18):
wood and always buy lumber that is rated for ground contact and
labeled for residential use. Now the good news is CCA treated
wood is no longer available for residential use as of 2004.
So if the pressure treated lumber that you're thinking of
using is less than 20 years old,yeah, you are likely safe.
(07:41):
This also means, though, that you should avoid using reclaimed
railroad ties or old utility poles.
Those were created treated with creosote and pensachlorophenol
and absolutely can release harmful compounds into your
garden soil. So if you're still feeling
uneasy about using pressure treated woods for creating a new
(08:04):
raised bed, then just choose those water and rot resistant
species. So untreated hemlock, Redwood,
black cherry, black locust, Osage orange or cedar, these all
are going to last for a lot of years without being treated and
they're going to eliminate that need for any chemical
preservatives. You can also paint those boards
(08:26):
with exterior latex paint or usea semi transparent oil based
stain and that will also slow down the decay.
Now they will eventually break down, but oftentimes you can
replace a board here or there and keep the entire bed intact.
In fact, a lot of my remaining wooden beds, the bottom board
(08:47):
has absolutely rotted out to where I can see the soil.
But the soil has been sort of jammed into that position for so
long. It's sort of stuck there and it
doesn't fall out unless I'm really digging deep into those
beds. And those beds have been there
for about 10 years. So I really could probably get
away with pulling off a board and have very little soil loss
(09:10):
and then just pop a new one on there and call it good.
But I'm just kind of in the modeof replacing them as they fall
apart. All right, so Next up we're
talking all of the non wood options, prefab metal beds,
stone, brick, concrete, grow bags and more.
Now that I have made the decision to turn my in ground
(09:31):
barn bed area into a raised bed garden, I am taking my time
picking out the colors that I want to use.
Planter box direct has 23 different colors to choose from,
plus three new textured colors. And since this bed is a whole
separate area, I don't feel the need to continue the same color
scheme as my other garden beds. I've typically gone with barn
(09:54):
red and light stone, but the sunset blue is we're really
getting my attention right now. All those colors offered by
Planterbox Direct are created using a silicone modified
polyester coating. This is the same coating that's
used on metal roofs. This coating is designed to
stand up to years of heat and UVrays without degrading.
(10:17):
So I am super confident that I will not need to be replacing
these beds anytime soon. To go along with our special
series this month on creating new raised garden beds, Planter
Box Direct is giving you 20% offyour order and free shipping on
their 100% USA made steel beds. Just use code Just Grow 20 at
(10:38):
checkout now through October 15th to get this special deal
and choose your own beautiful durable raised planters.
Planter Box direct.com with codeJust grow 20.
The link is in the show notes. So what are our non wood options
for creating new raised beds? One option is galvanized steel,
(11:01):
which can last a really long time and is generally safe in
neutral or alkaline soils. Just be aware that really acidic
soils, so anything that's got aph of like less than 5 May
cause zinc to leach from galvanized steel.
Now since we're really controlling the soil that's
inside our raised beds, this shouldn't be a problem for too
(11:24):
many of us, but it's something to be aware of if you plan to
use galvanized stock tanks or wash tubs as a raised veggie
bed. The other thing is even though
these are galvanized to be rust resistant, if you're drilling
holes in the bottom of these tanks for drainage, which you
should be, then that's opening those beds up to rust from the
(11:46):
bottom up. Again, a very slow process, but
it is something to be aware of. The next option is the
prefabricated metal beds that wesee everywhere now.
Now, obviously I have my favorite brand, but there are
tons of options out there in a wide range of prices and very
different coatings. These beds are generally
corrugated galvanized steel thatis then coated in AUV resistant
(12:12):
coating of some sort. Most of them use an aluminum
zinc combo. One of the name brands is Alu
Zinc Planter. Box Direct uses a siliconized
polyester coating. Some of them don't tell you what
they're using. So the more well known brands,
so Planterbox, Direct, Birdies, Vigo, they list the attributes
(12:33):
of the coding, but random brandson Amazon or TikTok shop or
wherever do not. And that is a red flag for you.
Some of these prefabricated metal beds have been found to
contain lead and of course lead can leach and it can cause all
kinds of problems for us if we're in contact with it.
So do your due diligence when deciding on a manufacturer.
(12:56):
Don't just go by the looks or bythe cost.
If there is no information aboutthe construction of that bed or
where it's manufactured, I wouldlook someplace else.
Now, of course, there are plentyof other options too that just
require maybe a little bit more creativity and assembly on the
part of the gardener. So stone, brick, concrete, these
(13:18):
are all very durable and can be very convenient to use these if
they've been pulled from like anexisting project in your home or
maybe somebody else on Facebook marketplace has dug them up out
of their yard and they need to get rid of them for cheap,
right? You can get really creative with
the designs using these materials.
Round or Oval beds may be easierto create with these materials
(13:43):
than if you were using wood or metal.
You have a little bit more flexibility in just how tall you
want to make these and you can very easily just tuck smaller
little round or uniquely shaped beds using these materials into
little corners or spaces in between all your other larger
beds. Now if you're buying these
(14:03):
materials new, they are definitely more expensive than
our other options, but they're going to last just as long as
the metal beds will, if not longer.
I will say though, some cinder blocks may contain fly ash.
This is a coal byproduct that can actually contain heavy
metals. So cement blocks, cinder block,
(14:24):
concrete block, whatever you want to call them are all made
with cement and fine aggregates like sand or small stones.
Now unfortunately, depending on the quality of the
manufacturing, fly ash is also often included and the labels do
not give specific information onexactly exactly what aggregate
(14:46):
is used in the manufacturing of these blocks.
And honestly, if you're reusing blocks then you're not going to
have any idea. There is also very little
research on this topic and how it may affect garden soils when
it comes in contact with them. So if you opt for concrete
blocks, it is recommended to seal them with like a polymer
(15:10):
paint or something to limit the gardener's like repeated direct
contact with it and the contact with the soil.
Now finally, let's talk about fabric grow bags.
You might automatically think ofthose little three or five
gallon bags that come in like packs of 5 or 10 and they are
super light and they are super inexpensive.
(15:31):
Those are more akin to like container gardening than actual
raised planters. But the same material used to
make those are also used to makefull-sized garden beds.
I have 3 right now that are, I want to say 4 foot by 6 foot and
(15:51):
they're divided into these either 12 or 18 inch pockets for
planting. They're actually kind of cool.
We've also experimented with really large round 50 gallon all
the way up to 500 gallon fabric containers.
All of these have done pretty well for us in different
circumstances, and you might be surprised at how long those
(16:14):
larger ones actually can last when they are exposed to the
elements. The smaller ones are super easy
to like empty and store away, but something that's 100 gallons
or more is not. And we ended up actually leaving
them in place in the fields where we put them in.
And after about five years or so, they did degrade, but the
cost on them was so low. We definitely got our money's
(16:35):
worth. The downside to these planters
is that you have to research closely what they're made from.
The fabric, and I'm using air bunnies here, is often made of
one of several things. The first is polypropylene,
right? This is probably the most common
material used for fabric grow bags.
(16:56):
It's breathable, it's very sturdy.
It can definitely withstand the rigors of gardening.
It allows for really good air circulation and drainage, which
helps to prevent overwatering. It actually promotes healthy
root growth. The second is polyethylene.
This is another synthetic. It is also known for its
durability and its moisture resistance.
(17:16):
It's a little bit less breathable than polypropylene,
but it's still used in some growbags because it's very tough and
it is able to resist tears and punctures.
And then there are non woven fabrics.
These are popular because of their breathability, but also
their moisture retention. They allow really good airflow
(17:36):
to the roots. So this helps to prevent like
root circling and promotes that healthier plant growth.
Sometimes these like non woven fabrics are made from plastic
landscape fabrics. Sometimes they are other mixed
materials. The problem with all of these is
that the research on microplastic leaching from them
(17:57):
is very very limited. So I choose to treat these as
temporary containers rather thanlong term raised bed solutions.
Now there are some grow bags that are made from biodegradable
materials like jute or cotton orhemp.
(18:18):
Even bamboo I think is another option.
These are obviously more environmentally friendly.
They do provide good aeration and drainage that does make them
suitable for a lot of different plants.
And they obviously are particularly beneficial for
gardeners who are looking for more sustainable alternatives
than the sort of plastic based alternatives that we talked
about. They are a little bit more
(18:39):
pricey than the other versions, but they are still affordable
for what you're getting and theycan be a great option for raised
beds. OK, coming up bottoms up.
Do you need something at the bottom of your raised bed to
keep the soil in or the crittersout?
That's next. In most cases, if you are
(19:03):
placing your raised garden bed on a soil surface like out in
the yard, you do not need a barrier on the bottom.
A layer between the bed and the soil can actually restrict root
growth depending on what it is that you're growing.
It's also going to restrict the beneficial microbes that you
already have existing in your yard for making their way into
(19:27):
the soil that you add to the raised bed.
And so instead kill the grass orthe weeds or whatever where the
bed is going to sit just by layering down some cardboard
over the top. And that's just going to smother
them. Or you can sort of aerate and
turn the soil over underneath and just place the bed on top.
Now if the concern is weeds, just remember that you are more
(19:49):
likely to get weed seeds blowingin on the wind then you are to
have weeds growing up through a very deep layer of soil.
I mean the one exception to thismight be field bind weed.
I swear I have seen that stuff tunnel up through 18 inches of
soil. Everything else seems to get
choked out. I just I don't recommend any
(20:11):
kind of like weed barrier cloth at the bottom, especially at
those landscape fabrics. They tend to degrade and
oftentimes they are made from plastic so now you just have a
bunch of shredded like micro plastics in the bottom of your
bed. Burlap does work nicely if you
don't want to use the cardboard and it will definitely smother
things out. But again, it is also going to
(20:33):
degrade over time and that is okay because it's a natural
material. So I don't mind that one so
much. So if you need something at the
bottom, you really think that you need to choke out, you know,
any of the the, you know, grasses that are already
existing there or any weeds thatare existing there, then I
always recommend cardboard or like burlap or something.
Now, if burrowing animals like moles or moles are the problem,
(20:56):
then it is a good idea to place something at the bottom.
And I generally recommend hardware cloth.
So put that at the bottom of thebed before you start adding in
your soil. This is still going to allow
like the worms and such to come up through the soil in between
the hardware, but it's going to prevent those burrowers from
(21:17):
coming up to the root zone and destroying your plants.
Now, if you're planting on a very rocky surface or on top of
like landscaping rocks, then youmight want to use the cardboard
or the burlap to help keep the soil from washing out from the
bottom of the bed while it's getting settled in.
(21:37):
Because you don't, you know, if you're putting these beds down
on top of a very uneven surface where there's going to be gaps,
then the soil can actually fall out of those gaps as you're
filling it in. Once it's sort of in and it's
packed in and it's settled, thenthis is less of a problem.
And it will be okay for that cardboard or that burlap to sort
(21:57):
of break down and go away, incorporate into the soil.
But in the meantime, having something like the cardboard or
that burlap at the bottom is going to help to kind of keep
that soil from washing out whileit's getting settled in.
And there may be instances whereyou actually do need a physical
bottom on the bed. So if you're planting over top
of very chunky rocks or you're placing a raised bed on like a
(22:21):
concrete slab or on a deck, you might want to add a bottom onto
your bed. So using the same material that
you are constructing the bed from, whether that's wood or
brick or metal, would be a really good idea.
Or you can go with some other material.
I just don't recommend plastics because again, we're not sure
(22:42):
what the leaching from that plastics is doing to the soil
and how much of that is affecting us and our plants.
Just always be sure if you do have a bottom that you have to
place on the bed that you createdrainage holes in a way for any
excess water to run off and awayfrom those beds so that you
(23:04):
don't end up waterlogged. And that's something that we're
going to talk about next week too, when we talk about filling
our raised beds. OK, we've covered a lot today
about what you can use to build your raised beds, the pros and
cons of the different materials,and whether or not you need a
bottom layer to keep weeds or critters out.
(23:26):
At the end of the day, the best choice for you comes down to
budget, longevity, and just how you want your garden space to
look and function. The good news is, there's no
right way to do it. You can get creative and still
grow a thriving garden, so don'tbe afraid to experiment with
(23:47):
different materials and shapes and layouts until you find what
works best for you. Like me, you might find that you
like combinations of a lot of different options, and that is
perfectly OK. If you found this episode
helpful, I would love for you toshare it with a gardening friend
who might be planning their own raised beds this fall.
(24:08):
Sharing the show is one of the best ways to help more people
just grow something. Until next time, my gardening
friends, keep on cultivating that dream garden, and we'll
talk again soon.
Last week we talked about how todecide on the correct size of
raised bed construction for yourspecific needs in your garden.
Continuing the series this week,we're talking about the
materials we can use for that construction.
Whether it's reused materials, prefab purchases, or just
(00:20):
leftovers from another project, you really can build a raised
garden bed out of almost anything.
So today I'll just grow something.
We're looking at what to build your raised beds with and
whether or not you need anythingat the bottom to contain the
soil or keep out pests. Gardeners sometimes worry about
(00:40):
chemical leaching from wood, thelongevity of the materials they
use, and how to keep weeds and clears at Bay.
So today we tackle it all. Let's dig in.
Hey, I'm Karen and what started as a small backyard garden 20
years ago turned into a lifelongpassion for growing food.
Now as a market farmer and horticulturist, I want to help
you do the same on this podcast.I am your friend in the garden
(01:04):
teaching evidence based techniques to help.
You grow your favourites. And build confidence in your own
garden space. So grab your garden journal and
a cup of coffee and get ready tojust grow something.
So we definitely have all the fall feels going on here right
now. It has been unusually cool in
the overnights. It has also been much, much
(01:25):
cooler during the daytime. And it just has me like pulling
out the hoodies and pulling out the flannels.
I know we're going to warm up again, you know, this week or
whatever, but it's been kind of nice to feel the fall coming in.
And so it got me thinking about putting some hoodies back into
the shop. So I've still got all the tank
tops and T-shirts and the mouse pads and all kinds of other
(01:47):
stuff in there, but I'm going toprobably go ahead and start
dropping in some of the cooler weather stuff.
So like the long sleeve stuff and the hoodies.
So just growsomething.com, go toshop and you will find all the
options in there. I put some fun stuff in there
earlier in like the late spring,early summer.
I kind of dig the Alexa weed, the garden design and some other
(02:10):
ones. So have some fun checking that
out. I'm definitely going to throw
some hoodies in there too. I have used so many different
types of materials to create raised beds over the years that
I've actually lost track. I haven't even come close to
exhausting all of the options. So scrap wood, obviously.
(02:31):
Prefabricated beds, old metal wash tubs and wash bins, old
leaky stock tanks, giant fabric growing beds.
All of the things I have tried aton of them.
You can use old bricks and stackthem into a bed, concrete
blocks, pavers, you can even usestraw bales or like old logs as
(02:51):
a way to create the perimeter ofthe bed.
And also sometimes you can use those as the planter themselves.
Although that last option acts more like a pot than a large
planter. But it's a pretty cool way to
work with just found materials. The decision for what type of
material you want to use comes down to a couple of things.
How long you want the material to last, what your budget is,
(03:15):
and your aesthetic. Now obviously if you want the
bed to be built once and last for decades, then you're not
going to choose straw bales or old logs that are going to break
down after a really short periodof time.
You might choose reclaimed wood because it's free and you can
just give it a coat of paint, extend its longevity, which is
(03:36):
what I did for many, many years.But eventually those will break
down, too. Those beds are being replaced
with new planter box direct bedsas they sort of fall apart.
And I also scored some very inexpensive fabric beds with
like, pockets that divide them into square foot, you know,
gardening spaces. And I'm using those as temporary
(04:00):
beds this year in some spots where I just needed some extra
plants. Now, I don't think those fabric
beds can stay in place over the winter if I want them to last
very long. So the soil will likely be
removed and I'll put it into my compost pile, and then I'll
store those beds away. But that may be a good option to
see if a particular layout worksfor you or if, like me, you just
(04:22):
needed some temporary extra space.
But I wouldn't leave fabric bedsin place for too long or they
will start to break down. If you're pulling up like old
pavers from a landscape project,you can use those to create a
bed depending on how many you have or if you score some cheap
concrete blocks someone's givingaway and just use that.
But if you have a specific design that you're going for or
(04:45):
you want something that will match the design or colors of
your house, you might need to spend a little bit of money to
get what you want. And often that means the beds
are going to last longer too. Even, you know, combinations of
materials may work in this respect.
So material choices. Let's start with wood.
(05:06):
Wood is the classic choice because it's relatively
inexpensive and it's easy to work with.
So soft woods like pine and fir are affordable, but they
definitely rot faster. Hardwoods like cedar and Redwood
are definitely more durable, butthey are costlier.
And some gardeners use pressure treated wood to extend that bed
(05:29):
life. And this is where we're going to
talk some science. There has been a long standing
adage among gardeners that you should not use pressure treated
wood to build your raised beds because you risk the chemicals
used in that wood, specifically arsenic, leaching into the
(05:51):
garden beds. But let me assure you, for newly
purchased pressure treated lumber this is no longer a
concern. Modern pressure treatment uses a
preservative called micronized Copper Azol, or MCA, and it
contains copper but no arsenic. Research from my alma mater,
(06:11):
Oregon State University, found that this type of lumber
increases soil copper concentration only within about
an inch of the wood and only by about 20 parts per million, and
that no excess copper was found in the vegetables that were
grown in those beds. So this means the risk of copper
uptake is extremely low. The primary concern might be to
(06:35):
direct contact between the gardener and the pressure
treated wood, or through accidentally inhaling or
ingesting large amounts of the soil that might contain some
copper. If this is a concern for you,
wear gloves when you're handlingthe lumber and try not to inhale
disturbed soil or just wear a mask.
Older treated woods are a different story.
(06:57):
Those contain chromated copper arsenate, CCA or creosote or
pentachlorophenol, and those should never be used to create a
raised garden bed. This means you need to know the
source of your pressure treated wood.
So if there is any question, be sure sure you are buying new
(07:18):
wood and always buy lumber that is rated for ground contact and
labeled for residential use. Now the good news is CCA treated
wood is no longer available for residential use as of 2004.
So if the pressure treated lumber that you're thinking of
using is less than 20 years old,yeah, you are likely safe.
(07:41):
This also means, though, that you should avoid using reclaimed
railroad ties or old utility poles.
Those were created treated with creosote and pensachlorophenol
and absolutely can release harmful compounds into your
garden soil. So if you're still feeling
uneasy about using pressure treated woods for creating a new
(08:04):
raised bed, then just choose those water and rot resistant
species. So untreated hemlock, Redwood,
black cherry, black locust, Osage orange or cedar, these all
are going to last for a lot of years without being treated and
they're going to eliminate that need for any chemical
preservatives. You can also paint those boards
(08:26):
with exterior latex paint or usea semi transparent oil based
stain and that will also slow down the decay.
Now they will eventually break down, but oftentimes you can
replace a board here or there and keep the entire bed intact.
In fact, a lot of my remaining wooden beds, the bottom board
(08:47):
has absolutely rotted out to where I can see the soil.
But the soil has been sort of jammed into that position for so
long. It's sort of stuck there and it
doesn't fall out unless I'm really digging deep into those
beds. And those beds have been there
for about 10 years. So I really could probably get
away with pulling off a board and have very little soil loss
(09:10):
and then just pop a new one on there and call it good.
But I'm just kind of in the modeof replacing them as they fall
apart. All right, so Next up we're
talking all of the non wood options, prefab metal beds,
stone, brick, concrete, grow bags and more.
Now that I have made the decision to turn my in ground
(09:31):
barn bed area into a raised bed garden, I am taking my time
picking out the colors that I want to use.
Planter box direct has 23 different colors to choose from,
plus three new textured colors. And since this bed is a whole
separate area, I don't feel the need to continue the same color
scheme as my other garden beds. I've typically gone with barn
(09:54):
red and light stone, but the sunset blue is we're really
getting my attention right now. All those colors offered by
Planterbox Direct are created using a silicone modified
polyester coating. This is the same coating that's
used on metal roofs. This coating is designed to
stand up to years of heat and UVrays without degrading.
(10:17):
So I am super confident that I will not need to be replacing
these beds anytime soon. To go along with our special
series this month on creating new raised garden beds, Planter
Box Direct is giving you 20% offyour order and free shipping on
their 100% USA made steel beds. Just use code Just Grow 20 at
(10:38):
checkout now through October 15th to get this special deal
and choose your own beautiful durable raised planters.
Planter Box direct.com with codeJust grow 20.
The link is in the show notes. So what are our non wood options
for creating new raised beds? One option is galvanized steel,
(11:01):
which can last a really long time and is generally safe in
neutral or alkaline soils. Just be aware that really acidic
soils, so anything that's got aph of like less than 5 May
cause zinc to leach from galvanized steel.
Now since we're really controlling the soil that's
inside our raised beds, this shouldn't be a problem for too
(11:24):
many of us, but it's something to be aware of if you plan to
use galvanized stock tanks or wash tubs as a raised veggie
bed. The other thing is even though
these are galvanized to be rust resistant, if you're drilling
holes in the bottom of these tanks for drainage, which you
should be, then that's opening those beds up to rust from the
(11:46):
bottom up. Again, a very slow process, but
it is something to be aware of. The next option is the
prefabricated metal beds that wesee everywhere now.
Now, obviously I have my favorite brand, but there are
tons of options out there in a wide range of prices and very
different coatings. These beds are generally
corrugated galvanized steel thatis then coated in AUV resistant
(12:12):
coating of some sort. Most of them use an aluminum
zinc combo. One of the name brands is Alu
Zinc Planter. Box Direct uses a siliconized
polyester coating. Some of them don't tell you what
they're using. So the more well known brands,
so Planterbox, Direct, Birdies, Vigo, they list the attributes
(12:33):
of the coding, but random brandson Amazon or TikTok shop or
wherever do not. And that is a red flag for you.
Some of these prefabricated metal beds have been found to
contain lead and of course lead can leach and it can cause all
kinds of problems for us if we're in contact with it.
So do your due diligence when deciding on a manufacturer.
(12:56):
Don't just go by the looks or bythe cost.
If there is no information aboutthe construction of that bed or
where it's manufactured, I wouldlook someplace else.
Now, of course, there are plentyof other options too that just
require maybe a little bit more creativity and assembly on the
part of the gardener. So stone, brick, concrete, these
(13:18):
are all very durable and can be very convenient to use these if
they've been pulled from like anexisting project in your home or
maybe somebody else on Facebook marketplace has dug them up out
of their yard and they need to get rid of them for cheap,
right? You can get really creative with
the designs using these materials.
Round or Oval beds may be easierto create with these materials
(13:43):
than if you were using wood or metal.
You have a little bit more flexibility in just how tall you
want to make these and you can very easily just tuck smaller
little round or uniquely shaped beds using these materials into
little corners or spaces in between all your other larger
beds. Now if you're buying these
(14:03):
materials new, they are definitely more expensive than
our other options, but they're going to last just as long as
the metal beds will, if not longer.
I will say though, some cinder blocks may contain fly ash.
This is a coal byproduct that can actually contain heavy
metals. So cement blocks, cinder block,
(14:24):
concrete block, whatever you want to call them are all made
with cement and fine aggregates like sand or small stones.
Now unfortunately, depending on the quality of the
manufacturing, fly ash is also often included and the labels do
not give specific information onexactly exactly what aggregate
(14:46):
is used in the manufacturing of these blocks.
And honestly, if you're reusing blocks then you're not going to
have any idea. There is also very little
research on this topic and how it may affect garden soils when
it comes in contact with them. So if you opt for concrete
blocks, it is recommended to seal them with like a polymer
(15:10):
paint or something to limit the gardener's like repeated direct
contact with it and the contact with the soil.
Now finally, let's talk about fabric grow bags.
You might automatically think ofthose little three or five
gallon bags that come in like packs of 5 or 10 and they are
super light and they are super inexpensive.
(15:31):
Those are more akin to like container gardening than actual
raised planters. But the same material used to
make those are also used to makefull-sized garden beds.
I have 3 right now that are, I want to say 4 foot by 6 foot and
(15:51):
they're divided into these either 12 or 18 inch pockets for
planting. They're actually kind of cool.
We've also experimented with really large round 50 gallon all
the way up to 500 gallon fabric containers.
All of these have done pretty well for us in different
circumstances, and you might be surprised at how long those
(16:14):
larger ones actually can last when they are exposed to the
elements. The smaller ones are super easy
to like empty and store away, but something that's 100 gallons
or more is not. And we ended up actually leaving
them in place in the fields where we put them in.
And after about five years or so, they did degrade, but the
cost on them was so low. We definitely got our money's
(16:35):
worth. The downside to these planters
is that you have to research closely what they're made from.
The fabric, and I'm using air bunnies here, is often made of
one of several things. The first is polypropylene,
right? This is probably the most common
material used for fabric grow bags.
(16:56):
It's breathable, it's very sturdy.
It can definitely withstand the rigors of gardening.
It allows for really good air circulation and drainage, which
helps to prevent overwatering. It actually promotes healthy
root growth. The second is polyethylene.
This is another synthetic. It is also known for its
durability and its moisture resistance.
(17:16):
It's a little bit less breathable than polypropylene,
but it's still used in some growbags because it's very tough and
it is able to resist tears and punctures.
And then there are non woven fabrics.
These are popular because of their breathability, but also
their moisture retention. They allow really good airflow
(17:36):
to the roots. So this helps to prevent like
root circling and promotes that healthier plant growth.
Sometimes these like non woven fabrics are made from plastic
landscape fabrics. Sometimes they are other mixed
materials. The problem with all of these is
that the research on microplastic leaching from them
(17:57):
is very very limited. So I choose to treat these as
temporary containers rather thanlong term raised bed solutions.
Now there are some grow bags that are made from biodegradable
materials like jute or cotton orhemp.
(18:18):
Even bamboo I think is another option.
These are obviously more environmentally friendly.
They do provide good aeration and drainage that does make them
suitable for a lot of different plants.
And they obviously are particularly beneficial for
gardeners who are looking for more sustainable alternatives
than the sort of plastic based alternatives that we talked
about. They are a little bit more
(18:39):
pricey than the other versions, but they are still affordable
for what you're getting and theycan be a great option for raised
beds. OK, coming up bottoms up.
Do you need something at the bottom of your raised bed to
keep the soil in or the crittersout?
That's next. In most cases, if you are
(19:03):
placing your raised garden bed on a soil surface like out in
the yard, you do not need a barrier on the bottom.
A layer between the bed and the soil can actually restrict root
growth depending on what it is that you're growing.
It's also going to restrict the beneficial microbes that you
already have existing in your yard for making their way into
(19:27):
the soil that you add to the raised bed.
And so instead kill the grass orthe weeds or whatever where the
bed is going to sit just by layering down some cardboard
over the top. And that's just going to smother
them. Or you can sort of aerate and
turn the soil over underneath and just place the bed on top.
Now if the concern is weeds, just remember that you are more
(19:49):
likely to get weed seeds blowingin on the wind then you are to
have weeds growing up through a very deep layer of soil.
I mean the one exception to thismight be field bind weed.
I swear I have seen that stuff tunnel up through 18 inches of
soil. Everything else seems to get
choked out. I just I don't recommend any
(20:11):
kind of like weed barrier cloth at the bottom, especially at
those landscape fabrics. They tend to degrade and
oftentimes they are made from plastic so now you just have a
bunch of shredded like micro plastics in the bottom of your
bed. Burlap does work nicely if you
don't want to use the cardboard and it will definitely smother
things out. But again, it is also going to
(20:33):
degrade over time and that is okay because it's a natural
material. So I don't mind that one so
much. So if you need something at the
bottom, you really think that you need to choke out, you know,
any of the the, you know, grasses that are already
existing there or any weeds thatare existing there, then I
always recommend cardboard or like burlap or something.
Now, if burrowing animals like moles or moles are the problem,
(20:56):
then it is a good idea to place something at the bottom.
And I generally recommend hardware cloth.
So put that at the bottom of thebed before you start adding in
your soil. This is still going to allow
like the worms and such to come up through the soil in between
the hardware, but it's going to prevent those burrowers from
(21:17):
coming up to the root zone and destroying your plants.
Now, if you're planting on a very rocky surface or on top of
like landscaping rocks, then youmight want to use the cardboard
or the burlap to help keep the soil from washing out from the
bottom of the bed while it's getting settled in.
(21:37):
Because you don't, you know, if you're putting these beds down
on top of a very uneven surface where there's going to be gaps,
then the soil can actually fall out of those gaps as you're
filling it in. Once it's sort of in and it's
packed in and it's settled, thenthis is less of a problem.
And it will be okay for that cardboard or that burlap to sort
(21:57):
of break down and go away, incorporate into the soil.
But in the meantime, having something like the cardboard or
that burlap at the bottom is going to help to kind of keep
that soil from washing out whileit's getting settled in.
And there may be instances whereyou actually do need a physical
bottom on the bed. So if you're planting over top
of very chunky rocks or you're placing a raised bed on like a
(22:21):
concrete slab or on a deck, you might want to add a bottom onto
your bed. So using the same material that
you are constructing the bed from, whether that's wood or
brick or metal, would be a really good idea.
Or you can go with some other material.
I just don't recommend plastics because again, we're not sure
(22:42):
what the leaching from that plastics is doing to the soil
and how much of that is affecting us and our plants.
Just always be sure if you do have a bottom that you have to
place on the bed that you createdrainage holes in a way for any
excess water to run off and awayfrom those beds so that you
(23:04):
don't end up waterlogged. And that's something that we're
going to talk about next week too, when we talk about filling
our raised beds. OK, we've covered a lot today
about what you can use to build your raised beds, the pros and
cons of the different materials,and whether or not you need a
bottom layer to keep weeds or critters out.
(23:26):
At the end of the day, the best choice for you comes down to
budget, longevity, and just how you want your garden space to
look and function. The good news is, there's no
right way to do it. You can get creative and still
grow a thriving garden, so don'tbe afraid to experiment with
(23:47):
different materials and shapes and layouts until you find what
works best for you. Like me, you might find that you
like combinations of a lot of different options, and that is
perfectly OK. If you found this episode
helpful, I would love for you toshare it with a gardening friend
who might be planning their own raised beds this fall.
(24:08):
Sharing the show is one of the best ways to help more people
just grow something. Until next time, my gardening
friends, keep on cultivating that dream garden, and we'll
talk again soon.
Popular Podcasts
Stuff You Should Know
If you've ever wanted to know about champagne, satanism, the Stonewall Uprising, chaos theory, LSD, El Nino, true crime and Rosa Parks, then look no further. Josh and Chuck have you covered.
Ruthie's Table 4
For more than 30 years The River Cafe in London, has been the home-from-home of artists, architects, designers, actors, collectors, writers, activists, and politicians. Michael Caine, Glenn Close, JJ Abrams, Steve McQueen, Victoria and David Beckham, and Lily Allen, are just some of the people who love to call The River Cafe home. On River Cafe Table 4, Rogers sits down with her customers—who have become friends—to talk about food memories. Table 4 explores how food impacts every aspect of our lives. “Foods is politics, food is cultural, food is how you express love, food is about your heritage, it defines who you and who you want to be,” says Rogers. Each week, Rogers invites her guest to reminisce about family suppers and first dates, what they cook, how they eat when performing, the restaurants they choose, and what food they seek when they need comfort. And to punctuate each episode of Table 4, guests such as Ralph Fiennes, Emily Blunt, and Alfonso Cuarón, read their favourite recipe from one of the best-selling River Cafe cookbooks. Table 4 itself, is situated near The River Cafe’s open kitchen, close to the bright pink wood-fired oven and next to the glossy yellow pass, where Ruthie oversees the restaurant. You are invited to take a seat at this intimate table and join the conversation. For more information, recipes, and ingredients, go to https://shoptherivercafe.co.uk/ Web: https://rivercafe.co.uk/ Instagram: www.instagram.com/therivercafelondon/ Facebook: https://en-gb.facebook.com/therivercafelondon/ For more podcasts from iHeartRadio, visit the iheartradio app, apple podcasts, or wherever you listen to your favorite shows. Learn more about your ad-choices at https://www.iheartpodcastnetwork.com
Dateline NBC
Current and classic episodes, featuring compelling true-crime mysteries, powerful documentaries and in-depth investigations. Follow now to get the latest episodes of Dateline NBC completely free, or subscribe to Dateline Premium for ad-free listening and exclusive bonus content: DatelinePremium.com