Hi, I'm Katie Wagner from Utah State University Extension Service in Salt Lake
County and we're out here at Wheeler Farm in the USU Extension demonstration garden.
And today we're going to talk about how to construct a simple raised bed to last.
And so I have Michael Baird here and Michael is from Sliver Creek Garden Beds
He literally builds about 500 beds a year and so he's got a lot of tips and tricks
to help us to better understand how to build a great raised bed for your garden.
So, first of all Michael, I want to start with materials that you might use and
types of wood and I know that you brought a couple different pieces of wood here to
show us.
Well, I like to use cedar or redwood when I build my garden boxes.
I like cedar and redwood because they last, they're naturally rot-resistant,
they're naturally pest-resistant, and they'll last a little bit longer than some
of the other wood choices that we can use.
And I think that they weather pretty. This is a piece of cedar that, you know,
is, you know, four or five years old that's weathered in the sun and will
eventually turn gray, but -
[Katie] Yeah, that's really pretty.
[Michael] It'll - I like the color, it'll last, this color won't make it last any
less time. You can stain them to keep the color
bright, but you don't have to. They'll be just as strong with or without
it, so I really like that
[Katie] Great, so if you want to go with a natural type of a wood, a cedar or a
redwood will be naturally rot-resistant.
[Michael] Mhmm
[Katie] Can be a little bit more expensive lumbar to purchase than say
pressure-treated lumbar.
Yeah, pressure treated is cheaper, um, I don't really like the look, most of my
clients don't like the look, but I do get people who want it to last a lot longer.
The pressure-treated will probably last a little bit longer, but we also add
chemicals and once again, those aren't a huge issue, it's not going to kill you
to use those, but I try to stay away from them when I can.
So, if you are using pressure-treated lumbar, if that's what's available to you
and you wanted say to ensure that you didn't have any sort of chemicals from the
wood leaching into the garden soil, one option is that we can line the beds.
[Michael] Yeah
[Katie] And you did bring some lining materials.
[Michael] I did. This is - this is - that's just what they
come in, so - this is industrial weed barrier from one of the nurseries.
Sorry, we've got this sitting here. I typically cut it down.
I would just cut a whole row in half and then I've got the perfect size for my beds
to line them. But I use these to keep the chemicals out
and also to keep the soil in. A lot of times when you build boxes, the
wood will have knot holes, it will have imperfections, it's a wood box, so I keep
the soil from leaching through the outside of the box with something like this and
make the boxes last a little bit longer as well no matter what wood you decide to
use.
[Katie] Okay that's great. And probably one thing that's really
important to mention too is that if you do plan to line the sides of the box, you
want to make sure that you don't line the bottom as well because you want to make
sure that you have a avenue for water to escape and drain away.
If you're using some of these weed barrier cloths they actually will leach water
through them. If you've got one like that, if you've got
a large problem with weeds, you can put that down at the bottom it will still
leach the water, but you won't get some of the weeds up through the bottom, but I
would never do it with a plastic, you know, I want to be able to have it
drain.
And I know you were mentioning a little bit too, some of your experience with
using plastic as opposed to the weed barrier cloth, some of the problems that
you've noticed over the years.
You can get UV resistant plastic, but plastic degrades.
And that's one of the biggest problems I've had with it is that in as little as a
year, any plastic that's exposed to the sun is going to break and get brittle and
fall apart and it's just, it's a total mess in my box, and so I've switched
to the weed barrier cloth because it just doesn't degrade.
It'll last 10 or 15 years without it falling apart.
If I get the good stuff from the nurseries you can get it from a number of stores,
but I try to go to a local nursery and find heavy duty industrial stuff.
It's a little bit more expensive, but not much and you can find it at any nursery
nearby. So, that's the stuff I use.
Great, okay. So maybe let's talk sizing of the boxes
when we're doing our measurements and getting ready to build our boxes.
What might be an ideal size to build your box at?
I had a number of people ask me for a really large boxes, but the bigger the box
gets, the more soil you need as well and it's harder to reach the middle.
This box is 3 feet wide and that's the inside measurement here which means that
when I'm on the outside of a box I can reach the inside really easily and I like
to be able to sit when I garden without having to bend or stretch or fall over and
not put any pressure on the soil. Anytime I put pressure on that soil, I can
pack it, which is one of the reasons we do these boxes, we don't want a compacted
soil.
[Katie] Right?
[Michael] We want nice great soil so any time I push down on it or step on it I
make the soil harder and the plants harder to grow.
[Katie] Okay, great so that's 3 foot wide.
[Michael] 3 to 4 feet, once again it's up to you how wide you want it, just
whatever's comfortable for you. If you're a shorter person, do 2 and a
half foot wide boxes, you know, I use 3 or 4 feet because the wood usually comes
8 feet and I've got really easy measurements and I can cut a board in
half and I don't waste a lot of wood as well.
[Katie] Okay.
[Michael] So that's another nice thing to think about.
[Katie] Okay, Michael. We talked a little bit about width, but
how long can you build your raised beds?
So, that's just going to be dependent on the wood that you get.
Most wood will come about 8 feet, you can get lengths 12 or 16 and people, a lot of
people will lean towards that because they want one big long box, but one of the
problems with the long boxes is the wood warps.
All that soil behind your box is going to put pressure on it and the longer that
box is, the more pressure it is and your box won't stay square over time.
And that's one of the biggest problems we have.
People do 16 or 20 foot length beds and they have them turn into large ovals after
a couple of years. Also, I never would - when doing a box, I
always want one solid piece per side, I don't ever want to connect boards like
this because that's going to put pressure on it.
If I build a box with the two ends sitting together like this, eventually the wood's
going to push those boards apart, so I want my boxes with one solid piece per
side, not multiple pieces per side if I can do it.
[Katie] Great
So 6 to 8 feet is really good without getting warped, you know, the boards
don't warp and so if I want a 16 foot length, I'd do two 8 foot boxes instead of
one 16 foot. You'll have better results.
And I get pathways between those boxes that I can walk through and I don't have
to fill those with soil. You know, a tomato plant is so large, you
know, when I put a tomato plant in it can spill over the outside of the box and I
don't waste space. If I just have a giant box that's covered
by plant material, it's a waste of space.
Great, okay, so I guess let's get into the nuts and bolts in terms of putting a box
together and maybe you wouldn't mind sharing with us what kind of materials
you're going to need to build a raised bed.
[Michael] So you're going to need a couple different saws.
You're probably going to need a table saw, at least a circular saw or a chop saw.
The materials - or sorry the saw you use isn't as important as just that you use
proper safety methods when you do it. Safety glasses all the time and you know,
using the safety features of those things involved.
[Katie] Absolutely.
I also like to use coated screws whenever I do my boxes, you can see I've got coated
screws. Those are going to stop - sorry, coated
screws will not leach ugly colors onto your box in the future, so if people have
to see those screws then they won't discolor the wood around it if you use a
coated screw. You'll also need to drill, we talked about
this earlier, you have to pre-drill your holes in wood.
Any type of cedar or redwood splits really easy, so we drill a hole with a drill bit
first and then put our screw in at all times.
Especially because a lot of the times when we do these screws we go really close to
the end of a board and on the end of a board, we're going to have a higher
likelihood of that wood splitting if we don't pre-drill a hole.
So drills, saws, and then coated screws is my biggest thing for people.
Great, and you actually brought a couple of sort of corners that are built here and
maybe you don't mind just sharing with us kind of the construction of the corner, I
know that anchoring the corners in raised beds is really important.
That's one of the common mistakes I see is that people don't anchor the corners
properly. And then the wood starts to split away
at the corners just with all of the weight of the wet soil, the water, pushing out
against the corner of the raised bed.
What a number of raised beds I see would look like this in the bottom.
They'd actually just put that straight onto their soil and that's just a huge
mistake, I've seen that if instead I build - just leave my corners a little bit
longer, just a few inches like this, I can actually dig a hole and bury that in the
ground and then this box doesn't bow and change shape as fast.
So it's not a lot of extra wood to just make these, whether you do them internally
or externally, and we'll show you that in a second an external frame, we need to do
something to anchor them in, so this one we used just a little bit longer piece of
wood because I already have it, this one I used a 4x4, I can bury this little extra
piece of 4x4, this will be a little bit stronger, it will last a little bit longer
than this thinner board. But you can also use materials like
rebar, cement stakes, you know, just to pound some rebar into the ground and put
that rebar on the outside of our wood so there's something that's holding our wood
from changing shape over the course of the life of that box.
I want to be able to make these things look good from day one and last us for
years and years.
Sometimes too if you have those things on the outside of your raised bed, it can be
a nice sort of vertical growing structure for some of our vining plants whether it's
a vine tomato or peas or some of those sorts of things to actually climb up and
so it can kind of form a different function for raised beds as well.
I've done plenty of raised beds where we have rebar that we've pounded into the
ground a foot and then we've left it 2 or 3 feet high on the outside and they
just run strings across the outside and will plant their peas or cucumbers right
along the outside edge of the box and they get a vertical wall.
Which is really fun to - and you can make a lot of fun decorative things with that
as well, just having fun with something that's structurally important, but let's
make it useful as well.
Absolutely, and you also could use it for pest management so you needed to throw
some remade cloth over it to exclude some pests.
[Michael] Keep the deer and the chickens out of your garden beds, absolutely.
Okay, great! So maybe we could talk a little bit about,
you were talking about the corners, about different ways that you can construct
corners, and so let's -
So this corner is the wood on the outside, this corner would be the inside - this
would be the outside of the box, this would be the inside of the box.
I lose a little bit of space with my board here, that's not a huge deal, but the
screws are also exposed. I'll show you on my box here we build them
with the corners on the outside, one, to keep the screws intact and to make the box
a little bit stronger.
[Katie] Okay, so let's take a look at that.
[Michael] We're going to flip this one sideways.
[Katie] Yep.
Okay, so I have to say Michael, not only is this a good structural design, but also
it's really aesthetically pleasing on this raised bed, so how did you construct this
corner?
So, this is where I need a table saw. I would take a table saw and cut 1/4 of
a 4x4 out to get an external frame on this box.
A few reasons I do that: one, I don't see any screws.
[Katie] Right.
All my screws are hidden and so I don't get the staining of a screw, I don't get
that ugly look. It looks a little bit more finished this
way. The other reason is this wood is now on
the outside of my side wood which gives me added strength so that it's not just
the screws holding these boxes together. I'll bury this corner here a couple inches
in the ground which keeps it from bowing and it'll also give that strength so that
as the dirt presses on the outside of this wood, the wood holds it in place, not just
a screw. You know, screws rot, the screw holds the
rot and so the biggest problem I see with a corner similar to this is that over the
time, this wood will pop off. Dirt will push so hard on this that these
screws rot away and they pop off. But with this one we've got a much longer
lasting corner on here, so if you've got the resources to use a table saw,
once again, I can keep a corner that lasts longer and is stronger for the life of the
box.
Great, the other thing I noticed about this box is that you have this awesome
sitting lip that we were sitting on when we started this video, which is really
fantastic for gardeners to just have a resting place, but also if you have some
limited mobility it's a great place to come and settle and reach in and do your
gardening and so if we wanted to install a sitting lip like this, what would we
need to do?
Well, I actually designed this because my dad's 78
[Katie] Oh, okay! There you go.
And he needed a place to sit when he did it, he didn't want to bend over.
So many people ask me for boxes that are two feet tall and it's really impractical
to get that much soil. To get 2 or 3 feet of soil or they want
them waist high. And I think that this is a happy marriage
between the two, I still get a box that has enough soil, but I don't have to
waste, I don't have to fill 3 feet of soil it's just so expensive.
But for this box it's just important to measure - you know, I did it - this box is
3 feet by 6 feet so I had to get an 8 foot long board and cut it down to go a little
bit over the edge and then this is the only place I have my exposed screws, but
once again I just make sure that I screw those into my existing boards and spend
a little bit of time measuring and doing it.
When I build this box, this is by far the longest period of time I spend on it is
building the top, it takes a little bit more work and a little bit more skill,
but it makes a long-term better method of using the box.
I don't want to bend over all day either, so something like this with a lip.
You could do it with any type of materials.
I've reinforced the corner in here, which once again makes me lose a little bit of
space, but it makes this corner stronger because I'm overhanging on both sides.
But as you can see, it's strong enough for us to sit on and I've had mine for 5 years
and they're still just as strong to sit on and I don't have the issue of
you know, sitting on a lip edge or standing the entire time I use the box.
Great! Okay, so now that we have a raised bed
built, we need to position it in the garden, so first of all, it's probably
important to note that if you're growing edible crops, that you want it in an area
of your yard that has sufficient sunlight. So fruiting and rooting crops, things like
tomatoes, peppers, eggplants, or even beets or carrots or things like that, we
want to have at least 6 to 8 hours of direct sun a day.
Some of the crops that we eat the leaves, the foliage of, we can get away with a
little bit less, but probably at least 6 hours of direct sun a day.
[Michael] For things like spinach and lettuce and - yeah
For things like spinach and lettuce and some of those sorts of things, but also
when we're placing this box is it important that we level the ground when we
are settling it into our garden spot?
So, a number of people will install boxes for - have hills they put them on and so
we will dig away the higher part of the hill and make sure these boxes are level.
I get rivers all the time if we don't, you know, you'll get a river and I don't want
a river in my garden box, I want everything to be nice and flat so the
water can drain straight down into the box instead of rolling to one side and
pooling. So I will absolutely get a level out when
I do it and put them as level as I can get them.
They don't have to be perfect, the soil will take care of a little bit of that,
but they need to be as good as we can get them.
[Kate] Great
[Michael] It's practical to do it.
So definitely want to try to level our boxes and our spot even if it takes a
little bit of digging away of the soil or digging into a hillside to make sure that
we can get that level.
Well and you know, Katie, that a box - the depth of a box makes a big difference.
It's difficult to grow tomatoes or any plant really in 3 or 4 inches of soil.
A lot of people want to do boxes that are only one or two 2x4s high and I just don't
recommend that for people. I want more soil than that.
I want root crops especially to have plenty of space to grow, but also when a
box is tall like this, the soil will warm up faster and we know that tomatoes and
other plants grow based on how warm the soil is, not how warm it is outside.
So if the roots of a tomato can get warmer, they'll grow faster and they'll
do better.
Yeah, that's a great advantage to raised beds, is you get to grow a little bit
earlier in the growing season because you get that soil to warm up a little bit
sooner.
And with a short 4 inch bed you just don't get that advantage.
Alright, one other thing to think about, Katie, when you're doing your boxes and
where you're putting them is access to water.
[Katie] Oh yeah, right.
Where I'm going to get my water from for sprinklers, am I gonna over spray it with
the sprinklers I've got or am I going to install drip systems?
I know some of the boxes you have here at the demonstration garden have some
great drip systems, we should look at those, but just what am I going to do for
water? How am I going to water this?
And I need a hose to water the day I plant, not just the drips later on in the
future. So where are we going to get water from
and where we get that.
Great, okay, so I think we should also definitely talk briefly about different
fill materials which you can use for raised bed boxes.
You can of course amend top soil, if you're going to do that, your native
soil, you want to make sure that you add sufficient organic matter to the -
[Michael] And a lot of it!
And a lot of it, yeah, so you know, usually we recommend somewhere in the
range of about 50 percent native soil, 50 percent well composted, high-quality
compost material amended to your boxes. You can't just put top soil in your boxes.
And a lot of the cities here in Utah sell composted material at a really cheap
price you can get it there, you don't have to pay for the expensive bags at the
stores. You can get really cheap stuff by the yard
at city dumps and at other places around town, so there's a number of great places
to get it, just ask your local neighbors, ask your extension office where they might
get it, things like that.
[Katie] Yep, a lot of different options for that.
I say at least half organic matter as well whenever I tell my clients to get when
they fill their boxes.
So another option, of course, is that you can get a soil-less potting mix or a
potting medium which is a mix of organic matter and some other materials like
perlite or vermiculite. It doesn't actually have soil in it sand,
silt, and clay, but it is designed to be used in containers and can also be used in
raised bed boxes as well.
And that's typically a little bit more expensive, but they're great - those mixes
work great. I've found that I can usually get a yard
of compost for about 20 bucks from the cities and I can get a yard of top soil, I
try to find weed-free stuff for about the same price - 20 to 25.
You can get cheaper stuff, but it's always full of weeds, so make sure you find out
where your top soil is coming from and if you're doing one - a lot of the
nurseries also sell premixed garden mixes that'll have top soil and vermiculite or
perlite in them and those are great, but they usually run about 75 to 100 dollars
a piece per yard to get those, so you can make it cheaper, but they're really good
when you get those.
So I think that's great because the one thing we haven't talked about much through
this video is cost, how much it's going to cost a homeowner to put together one of
these raised beds. So we talked a little bit about making
sure that you factor in the cost of the filling material, but you also need to
factor in the cost of your lumbar and so Michael, what would a box like this run us
in terms of lumbar cost?
So a big deal will be the type of material you use.
Cedar's usually a little bit cheaper than redwood, but redwood from most stores you
can only get it in 2-by materials: 2x4s, 2x6s, 2x8s.
A box like this size 3x6 out of redwood is about 150 dollars of materials.
On a cedar you can find a little bit cheaper and if you go to something like a
cedar fence board that's only a half inch thick, you can probably build a box this
big for about 75 to 85 dollars. It's not a huge cost on that.
[Katie] So what are the pros and cons of using a thicker board like this versus
a thinner board like that.
So the thinner boards you've got to do smaller boxes.
I can't do an 8 foot long box out of a fence board.
It's just - it won't hold up - over time that's going to bow too much.
Also don't just go to the big box stores or your nurseries though because that's -
fencing companies is a great place to find alternative materials that you
wouldn't normally see at a industrial supply store or building supply store.
Right, so another place you could go to shop around to look for lumbar.
Yeah, fencing material stores are a great source to find good materials that are
a little bit thicker than you might find at those stores and you might be able
to find them at cheaper prices too because they're selling in bulk.
And just cedar or just redwood they sell.
Great, and of course if you don't feel like you can build your own raised bed or
you don't have time to build your own raised bed or whatever it may be, there
are also some kits that are available through different companies that you can
purchase that will work as well.
[Michael] Yeah, online you can find kits you can, you know, you can find people
building them locally a lot of times, we build here locally, but once again, you
can find - build your own or find someone who knows what they're doing to build them
for you. You know what I mean?
[Katie] Right, absolutely. Great well thank you so for coming and
sharing your expertise with us today and I hope that we've inspired some people to go
out and build their own raised beds.
I think that your boxes don't always have to be - they don't just have to be
utilitarian let's make them pretty too.
[Katie] Aboslutely
You know, spend some time, spend a little bit of extra care on your boxes and you'll
have something that looks good and works for years.
Absolutely, so, yeah thanks again Michael and happy gardening and go out and build
that beautiful garden in your backyard.