00:00:00
If you have been gardening for any amount of time, you have
00:00:03
likely come across companion planting charts.
00:00:07
Maybe you have seen advice that says plant basil with tomatoes,
00:00:10
or just general advice to plant marigolds with everything
00:00:13
because they repel pests. But how much of this is actually
00:00:17
true? Companion planting can mean a
00:00:20
lot of things. Depending on what our goal is.
00:00:23
We can either be going for pest repelling properties, or we
00:00:27
could be aiming to keep weeds down.
00:00:30
We might be looking for soil health benefits or just
00:00:32
enhancing flavors or saving space.
00:00:35
Today I'll just grow something. We are sorting fact from
00:00:39
fiction. Some companion planting
00:00:40
practices do have solid evidence behind them, or I should say
00:00:44
solid science. But a lot of claims are more
00:00:48
anecdotal than evidence based. And in some cases we might be
00:00:52
doing some well intended pairings that may even backfire.
00:00:56
I'm looking at you marigolds. So we will talk about what the
00:01:00
research says about using specific plants to either deter
00:01:04
or attract pests, when companion planting works and when it
00:01:08
doesn't, which plants shouldn't be grown together and of course
00:01:12
the why behind that. And we'll touch a little bit on
00:01:17
using intercropping effectively in the home garden.
00:01:20
We are going to bust some myths and set the record straight.
00:01:26
Let's dig in. Hey, I'm Karen and what started
00:01:29
as a small backyard garden 20 years ago turned into a lifelong
00:01:33
passion for growing food. Now as a market farmer and
00:01:36
horticulturist, I want to help you do the same.
00:01:39
On this podcast, I am your friend in the garden teaching
00:01:42
evidence based techniques to help you grow your favorites and
00:01:44
build confidence in your own garden space.
00:01:47
So grab your garden journal and a cup of coffee and get ready to
00:01:50
just grow something. Before we jump in, I want to
00:01:56
shout out my patrons over on Patreon for their continued
00:02:00
support of this show by either supporting my coffee habits or
00:02:05
just supporting the show itself with monthly support.
00:02:08
I wanted to shout out our newest patron, Robin, who joined at the
00:02:12
BI Karen. A coffee level keeping me
00:02:14
caffeinated is a very good thing for everybody involved.
00:02:18
Trust me. And I truly appreciate you Robin
00:02:20
and all of my other patrons who support this show monthly.
00:02:23
And for those of you who have did to jump on to buy me a
00:02:27
coffee and send over a one time support in terms of a coffee or
00:02:31
three, if you are interested in supporting the show, you can do
00:02:35
that from patreon.com/just Grow Something or Buy Me a
00:02:39
coffee.com/just Grow Something. I will link to both of those in
00:02:43
the show notes. It absolutely means the world to
00:02:47
me when I get feedback from my gardening friends that tells me
00:02:51
that the content here is resonating with you and that you
00:02:55
are getting value. So thank you.
00:02:56
Thank you very, very much. So companion planting kind of
00:03:04
gets framed as this sort of magic bullet for pest problems,
00:03:10
but the reality is a little bit more nuanced than that.
00:03:14
And like I mentioned in the intro, there are a lot of
00:03:16
different reasons why we might want to do companion planting
00:03:21
and what that means for us in our garden.
00:03:24
So our goals with companion planting are going to dictate
00:03:29
what plants we actually plant to together as companions.
00:03:34
True companion planting works through a couple of different
00:03:38
mechanisms. The first one would be pest
00:03:40
confusion. So we talked about that a little
00:03:42
bit last week in the pest prevention episode.
00:03:46
We're talking about masking scents or disrupting the pest
00:03:50
host location. So we talked about those
00:03:52
appropriate and inappropriate landings theory where a new
00:03:57
insect is looking for a very specific set of traits in a
00:04:02
plant to understand or to recognize that it is the place
00:04:06
where it's supposed to be laying its eggs.
00:04:08
And it will land just to kind of test out whether or not that's
00:04:12
the right plant. And then it will land again.
00:04:14
And if it lands on a plant that isn't its host, that is
00:04:18
considered, it's considered an inappropriate landing, then that
00:04:21
kind of resets the whole process and they start all over again.
00:04:24
So this is confusing the past. It also can be done in terms of
00:04:28
scents. And by scent we usually mean the
00:04:33
chemical signals that it's giving off, which to us that
00:04:35
smells like something very specific, but to pests it might
00:04:39
smell a little bit, you know, differently than that.
00:04:41
But they're looking for very specific scents or chemical
00:04:44
signals for the plants that they normally either use as a host or
00:04:48
predate on. And if we can use companion
00:04:51
planting to mask those scents and disrupt all of that, then
00:04:55
that is going to be successful. That is a successful companion
00:04:59
planting. So that's pest confusion.
00:05:02
The second one would be trap cropping.
00:05:04
So essentially this is sacrificing 1 plant to protect
00:05:10
another one. I actually discovered a really
00:05:13
good trap crop for kale specifically like curly kale and
00:05:18
other brassicas when I planted dinosaur kale for the first time
00:05:23
and I had it in one particular field where I was planting a lot
00:05:26
of my brassicas. So I had my curly kale and I had
00:05:29
my mustards, and I had broccoli and cauliflower and cabbage and
00:05:37
bok choy and a bunch of other greens that were all kind of in
00:05:39
that same sort of family. And I planted dinosaur kale for
00:05:44
the first time. And the dinosaur kale was torn
00:05:49
to shreds. And this was before I really
00:05:52
started relying heavily on insect netting, so most of my
00:05:55
stuff was not covered at this point.
00:05:58
That dinosaur kale looked like Swiss cheese.
00:06:00
The holes in those leaves from the cabbage moths and the
00:06:04
cabbage butterflies larvae as it has.
00:06:07
So all those little caterpillars, the cabbage
00:06:09
loopers had just destroyed that dinosaur kale.
00:06:13
But in the process of them doing that, the majority of my other
00:06:17
brassicas were being left alone and that was my first time
00:06:21
really discovering the truth behind trap cropping and it was
00:06:26
attracting the pests away to their preferred crop and using
00:06:32
that crop as a way to draw them away from the other things that
00:06:34
I was trying to grow. My attempt this year at trap
00:06:39
cropping is for my zucchini and my yellow squash.
00:06:42
So I am going back to a traditional method of of trap
00:06:47
cropping for zucchinis and other squashes and that is using blue
00:06:53
Hubbard squash. So blue Hubbard squash is
00:06:56
another one that is a preferential plant for
00:06:59
everything that's in the squash family.
00:07:02
The squash buying bores and the cucumber or the the squash bugs
00:07:06
absolutely prefer the blue Hubbard squash plant for
00:07:10
whatever reason over the other ones that we will grow.
00:07:13
So the key here is to get the blue Hubbard squash to be a few
00:07:17
weeks more mature than the other plants.
00:07:19
And so the plan is to get the blue Hubbard squash planted out
00:07:24
in one bed and leave it uncovered.
00:07:27
I'm also going to plant marigolds at either end, which
00:07:31
you'll find out why here in a minute.
00:07:33
And then I'm going to plant sunflowers a little bit away
00:07:38
from that crop. And then on the other side of
00:07:41
that particular field is where I'm going to plant my zucchini
00:07:44
and my yellow squashes and my other summer squashes, which
00:07:48
will immediately be covered with insect netting.
00:07:53
And I will have nasturtiums at either end of those beds.
00:07:56
And then a little ways away, I'm going to have more sunflowers
00:07:59
in. Now, the idea is that the insect
00:08:02
pests are going to be more attracted to the blue Hubbard
00:08:04
squash #1 because it's going to be a little bit more mature and
00:08:07
#2 because it is the preferred crop #3 it will not be covered.
00:08:12
And so it'll be an easier target for those pests.
00:08:16
In addition to that, the sunflowers hopefully are going
00:08:19
to attract birds to feed on the sunflowers, which also are going
00:08:25
to feed on the insect pests that are in the blue Hubbard squash,
00:08:29
which will be very close by. And the idea here is that all of
00:08:33
those pests will go over to the blue Hubbard.
00:08:35
And so when it's time to uncover the yellow squashes and the
00:08:38
zucchini on this side, because obviously they have to be
00:08:41
uncovered in order to be pollinated, then it'll be less
00:08:44
likely to attract those pests to the other side.
00:08:48
I'm not thinking that this is going to completely, 100%
00:08:51
protect my zucchini in my yellow squash, but it's hopefully going
00:08:54
to draw away the majority of those insect pests and get them
00:08:57
over to the blue Hubbard. Now with trap cropping it, it
00:09:00
may not necessarily be just about drawing them away.
00:09:03
You might use it literally as a trap.
00:09:06
You're trapping these pests by in some way eliminating them
00:09:10
once they are in that crop. So this might be pulling that
00:09:14
crop completely and getting rid of it and the pests along with
00:09:18
it. This might be spraying something
00:09:21
like an, you know, insecticidal soap or something to knock that
00:09:24
insect pest population down so that they can't go over and
00:09:28
predate on your other ones. There's all kinds of ways to do
00:09:31
this, but that's the essential idea behind trap cropping.
00:09:34
Another way that we can effect companion planting is through
00:09:38
allelopathy. And allelopathy is basically a
00:09:42
plant that exudes chemical signals oftentimes either
00:09:47
through their roots or through their plant tissue that inhibit
00:09:52
some other growth or that do something with those chemicals.
00:09:57
So for example, with marigolds, we're talking about them
00:10:00
exudating a a root exit called thiopine that has been shown to
00:10:07
suppress root, not nematodes, right?
00:10:09
For sunflowers, this is going to be them keeping weeds at Bay.
00:10:14
So we'll talk about that a little bit more in depth.
00:10:15
But that is another way that we were, we would use companion
00:10:19
planting as a way to help prevent things or accomplish
00:10:23
things in the garden. And then we also can use
00:10:28
companion plants for attracting beneficial insects.
00:10:31
So this might be more of an idea of we're going to plant these
00:10:35
things in order to bring in natural predators or to bring in
00:10:39
more pollinators in order to help us combat some of the other
00:10:43
things that are going on in our garden.
00:10:45
You could also look at some of the inter planting that we do
00:10:50
and use and consider that some companion planting, especially
00:10:54
when in terms of maybe we're having some of the plants act as
00:10:57
a living mulch. So think about the three sisters
00:11:00
method, OK, if you're not familiar with the three sisters,
00:11:03
essentially it is a traditional way of growing three specific
00:11:06
crops. You're growing corn generally.
00:11:09
We're not talking about sweet corn here.
00:11:10
We're talking about dent corn or flour type corns.
00:11:13
So this is a dried corn, which means those stocks are going to
00:11:16
be out there for an extended period of time.
00:11:18
But at the same time you are planting beans, whole beans, at
00:11:22
the base of those corn plants so the beans can climb up the corn.
00:11:27
And then you are planting pumpkins or some other type of a
00:11:30
winter squash in and amongst the corn and it is crawling across
00:11:34
the ground and it is suppressing weeds.
00:11:36
So in this instance, this is a companion planting technique
00:11:40
that has nothing to do with keeping predatory insects out.
00:11:45
This is all about one plant supporting the other, supporting
00:11:48
the other, right? The the corn is acting as a
00:11:50
trellis for the beans. The beans are fixing nitrogen
00:11:53
into the soil that the corn really needs for its growth.
00:11:57
And then the squashes are vining in and amongst all of those
00:12:02
plants and they are providing ground cover which is helping to
00:12:05
keep the weeds at Bay. So not all companion planting is
00:12:09
specific to insect pests. It can be, but we just just want
00:12:14
to understand what mechanism we are interested in when we are
00:12:18
deciding what to plant with each one of our crops.
00:12:22
OK, so that's the first thing. But a lot of companion planting
00:12:28
charts are aimed at, you know, insect pests, and a lot of them
00:12:35
really rely very heavily just on anecdote.
00:12:38
And there isn't really any scientific backing to them.
00:12:42
This is not to say that it's not true, OK?
00:12:46
We've talked before about, you know, there's a difference
00:12:48
between causation and correlation.
00:12:50
And you know, us planting, you know, our basil with our
00:12:54
tomatoes and it's seeming like it the tomatoes tasted better
00:12:57
that year doesn't necessarily mean that's actually what
00:12:59
happened because there are so many other factors that could be
00:13:02
going on in our yards. This also doesn't mean that even
00:13:07
if it is backed by science, that it is necessarily going to work
00:13:10
for you in your garden because your soil type, your climate,
00:13:16
your amount of rainfall, all of those things are going to affect
00:13:22
how plants perform. And you know what type of
00:13:26
chemical signals or how strong the chemical signals are that
00:13:29
they give off. It's a lot of scientific based
00:13:32
information is based in a laboratory setting where things
00:13:35
are very well controlled. And as you have probably
00:13:38
experienced as a gardener, nothing is well controlled in
00:13:42
our gardens. Even when you find science
00:13:45
backed information, always think that you know, you should be
00:13:48
taking that with a little bit of a grain of salt and
00:13:50
understanding that it it may not work as well for you in your
00:13:53
garden as it did in the research garden or the research plot.
00:13:57
OK, so let's look at some popular companion plants and
00:14:01
what the research actually says or doesn't say about them.
00:14:05
And the very first one that we're going to talk about is
00:14:07
marigolds, because this is still probably one of the most
00:14:12
misunderstood companion plants in the home garden.
00:14:17
So this week I noticed my rose Bush from heirloom roses was
00:14:22
putting on a lot of beautiful green leafy growth.
00:14:25
And then I wondered if there was anything specific that I needed
00:14:28
to do with the plant in terms of spring care or more
00:14:32
specifically, pruning. I have mentioned I am not
00:14:35
someone who has had very good experiences with roses in the
00:14:39
past, and I honestly have no idea when it's a good time to
00:14:44
perform certain tasks just to make sure that it's living its
00:14:47
best little rose life. thankfullyheirloomroses.com has
00:14:51
a ton of resources to make my life easier and help me make the
00:14:55
best decisions for when and how to care for my rose, not just
00:15:00
now in its first full year in its pot out front, but for years
00:15:04
to come. They also provide emails every
00:15:08
week that give me more tips and tricks for keeping my rose
00:15:11
healthy, answering questions I didn't even think to ask.
00:15:16
This just makes me even more confident to go find maybe
00:15:19
another new rose to add upfront this year.
00:15:23
As a sponsor of the show, Heirloom Roses is offering you
00:15:27
20% off your purchase at heirloomroses.com by using code
00:15:31
Just Grow at Checkout. Make your purchase of beautiful
00:15:35
healthy own root Roses with confidence that you will have
00:15:39
the resources available to you to keep it healthy and beautiful
00:15:43
as the years go on. heirloomroses.com using code
00:15:47
Just grow at checkout to save 20%.
00:15:50
The link is in the show notes. I was one of those people who
00:15:56
recommended and used to plant marigolds with literally
00:16:01
everything in my garden. I planted them in and amongst
00:16:04
all of my zucchinis. I put them in and amongst all of
00:16:06
my cabbages and my brassicas. I put them in my tomatoes like I
00:16:09
used them everywhere. And let's be very clear, we're
00:16:13
talking specifically about French marigolds here.
00:16:16
So this is to Jetty's Pitula. You can also use Mexican
00:16:20
marigolds. They're a little bit different
00:16:22
the, the other one, not the friend.
00:16:24
The African marigolds do not work nearly as well in terms of
00:16:28
companion planting. You want the ones that really do
00:16:30
give off a very strong scent, that very particular scent.
00:16:34
The the African marigolds are very pretty, but they're not
00:16:37
really good in terms of companion planting for, for
00:16:42
specifically for insect pests. They might be, you know, good at
00:16:45
attracting pollinators and such, but not so much for insect
00:16:47
pests. OK, Like I mentioned with the
00:16:50
French marigolds, they do give off root exudates called
00:16:54
thiapine, and those have been shown to suppress nematodes.
00:16:59
OK. But when we're talking, and so
00:17:01
if you have nematodes and you have specifically root, not
00:17:04
nematodes in your tomatoes or other crops, then yeah,
00:17:06
absolutely you can use marigolds in terms of above ground crops
00:17:12
or above ground pests. I mean marigolds do not repel
00:17:17
all pests. As a matter of fact, they
00:17:19
actually are attractive to certain pests.
00:17:22
So this is where you have to decide what pest is it that you
00:17:25
want to repel if you are interplanting them amongst your
00:17:29
crops or what pests are you wanting to attract if you are
00:17:35
using it as a trap crop to draw pests away from your crop.
00:17:41
OK, so if you have problems with aphids, whiteflies, melon worms
00:17:48
and pickle worms, coddling moths.
00:17:51
So these are the moths that plague like your apple fruits
00:17:53
and your other palm fruits, those root nut nematodes,
00:17:57
diamondback moths or cabbage stem flea beetles, then yes,
00:18:03
marigolds are good at repelling those things.
00:18:07
OK, so this is something where if you have cabbage stem flea
00:18:12
beetles or you are dealing with aphids or whiteflies and you can
00:18:16
interplant marigolds in and amongst those crops that you are
00:18:20
trying to protect from those specific pests.
00:18:24
But if your pest problem involves squash bugs or squash
00:18:30
vine boars or cucumber beetles, you guys know those are my top
00:18:34
three, right? Leaf hoppers, spider mites,
00:18:38
tarnish plant bug, beet armyworm, cabbage loopers,
00:18:42
tobacco budworms, flea beetles, other than the cabbage stem flea
00:18:46
beetles. So the striped flea beetles or
00:18:48
the western black, all the other ones, right?
00:18:50
Or thrips. Then you need to be aware that
00:18:54
marigolds are actually attractive to those insects.
00:18:59
So now you know why I would be planting marigolds in with my
00:19:04
blue Hubbard squash. Because I want the squash bugs
00:19:08
and the squash vine boars to go over into those blue Hubbard
00:19:13
squashes. I want them away from my other
00:19:15
ones. The one thing that I failed to
00:19:16
mention too, is that the other thing that I'm putting over in
00:19:20
those blue Hubbard squash plants is some pheromone traps for the
00:19:25
squash vine bore. So I really want everything, all
00:19:28
those insects to go over to that crop over there.
00:19:31
And so I'm going to use the marigolds for that.
00:19:35
Now, in terms of like my brassicas where I used to always
00:19:38
plant marigolds in and amongst my cabbages and my broccoli and
00:19:43
my cauliflower, that was a really bad idea because my
00:19:47
problem is not with cabbage stem flea beetle, which is repelled
00:19:51
by the marigolds. My problem is with cabbage
00:19:54
loopers and marigolds attract cabbage loopers.
00:19:58
So that was not a really good idea for me.
00:20:01
I should be planting the marigolds away from my cabbage
00:20:04
and other brassica brassica crops.
00:20:07
So now what I do is when I plant my brassicas, I am planting
00:20:11
alyssum and I'm planting onions and I am planting lettuces and
00:20:14
intermixing all of that together.
00:20:16
And then I am covering it with that insect netting.
00:20:19
And then I am planting marigolds further away from those beds so
00:20:25
that I'm trying to draw those cabbage loopers away, right?
00:20:29
You need to plant according to your goal.
00:20:32
And marigolds are also attractive to the beneficials to
00:20:35
some of the beneficial, so like ladybugs and hoverflies and some
00:20:39
of the parasitoids and predatory insects.
00:20:41
So just plant according to your goal.
00:20:45
What is it that you are trying to achieve and use marigolds in
00:20:48
that instance? So what about like planting
00:20:52
basil with tomatoes? There actually is no strong
00:20:56
scientific evidence that basil does anything in terms of like
00:21:00
repelling tomato hornworms. As to what is often touted for
00:21:04
doing or improving the flavor of the tomato, there is anecdotal
00:21:09
data that suggests it might help repel thrips, and that maybe the
00:21:14
strong scent of the basil can help repel other insects.
00:21:19
And basil does attract pollinators.
00:21:21
This can actually be true of a lot of different strong scented
00:21:25
herbs and flowers, so this may not be specific to basil with
00:21:32
tomatoes. It doesn't mean again, that
00:21:35
these things aren't true, it just means that there isn't any
00:21:37
actual evidence. So there is no harm in planting
00:21:40
them together, but you just shouldn't rely on basil alone
00:21:44
for your pest control. So in addition to planting basil
00:21:49
in with my tomatoes, which I absolutely do, I absolutely do
00:21:52
this. I do think they go well together
00:21:55
and I will actually plant multiple varieties of basils.
00:21:58
So the green like Italian basils, sweet basils that we
00:22:01
harvest to, to sell in bunches of actual basil leaves.
00:22:05
I also plant different types of basil that maybe I'm not
00:22:09
harvesting to sell, but I'm allowing them to go to flower
00:22:12
because they do put off such beautiful flowers and a lot of
00:22:15
pollinators and other insects are attracted to that.
00:22:18
And of course that helps the tomatoes.
00:22:19
But also I am planting things like, you know, marigolds down
00:22:23
at the ends or in and amongst the the tomatoes.
00:22:27
And I am going to plant sunflowers down at the end of
00:22:30
that section of the garden to attract the birds.
00:22:32
And the birds are trying to pick off the things like the tomato
00:22:36
hornworms that might actually be damaging my tomatoes, but that
00:22:40
maybe the basil isn't repelling. I am not relying on just one
00:22:44
planting or one companion to do these jobs.
00:22:48
I am, you know, loading my bases and making sure that every
00:22:52
single thing that's out there has some sort of different
00:22:56
mechanism for helping me with these insect pests.
00:22:58
So no harm in planting them together, but don't rely on
00:23:01
basil alone for your pest control.
00:23:04
Another one would be porridge and planting that near squash or
00:23:09
tomatoes. Porridge flowers do attract
00:23:12
pollinators and they attract beneficial Wasps and some of
00:23:15
those beneficial Wasps are the ones that will predate on those
00:23:19
tomato hornworms. You may have seen images of
00:23:23
tomato hornworms with eggs laid on them.
00:23:26
It's fascinating to see. And what that is, is these
00:23:29
predatory Wasps have come in and have laid their eggs on the
00:23:32
hornworms. And when those eggs hatch, then
00:23:35
they essentially eat the hornworms.
00:23:36
And so you're kind of disrupting that hornworm reproduction cycle
00:23:40
right there. So, and there have been some
00:23:42
studies that do show if you were tomato hornworms on plants that
00:23:45
are planted near borage, You just have to remember that
00:23:48
borage grows very large, so you want to space it appropriately
00:23:51
to avoid shading anything nearby.
00:23:53
So it's fine to do them with the tomatoes because they're both
00:23:56
fairly tall. But if you're doing it near
00:23:58
squash, you want to do this like sort of appropriately, right?
00:24:02
I keep mentioning sunflowers and I use sunflowers to attract
00:24:08
birds that will predate on the insects in my garden.
00:24:12
And thereby I am helping to reduce the pests.
00:24:15
But I do shy away from planting anything too close to the base
00:24:20
of those plants because sunflower can be a highly
00:24:24
allelopathic plant. It's phytotoxic potential has
00:24:30
been shown on crops and weeds in not just laboratory settings,
00:24:35
but also in greenhouse and field trials.
00:24:38
And they've done all kinds of tests on this with different,
00:24:42
you know, a variety of factors like the concentration of how
00:24:45
many sunflowers are growing and the different species and the
00:24:47
different genotypes. So, you know, again, sunflower
00:24:51
are another one that kind of gives off these, these root
00:24:54
exudates that are chemicals that are going to inhibit the growth
00:24:59
of other plants in and around the base of the sunflowers.
00:25:03
Which means that sunflowers are a good crop to plant for
00:25:06
suppressing weeds, especially annual weeds, because it's going
00:25:10
to prevent them from coming up. But it may not be something that
00:25:12
you want to plant within a few feet of any crop that you
00:25:15
actually intend to harvest. Which it's kind of a shame
00:25:19
because, you know, we talked about the Three Sisters method.
00:25:21
And if you think about a sunflower, they have such real
00:25:25
good sturdy stalks. You would hope that it would be
00:25:27
something that you would be able to use as like a natural trellis
00:25:31
like the corn in the three Sisters method.
00:25:33
But unfortunately, most crops are not going to be able to
00:25:36
handle the chemical signals or the chemicals that are being
00:25:40
released from those roots. And if they are something that
00:25:44
could handle those allelopathic properties, the other way a
00:25:49
plant could be allelopathic, meaning it is preventing the
00:25:52
growth of things near it is to be basically a nutrient hog.
00:25:56
Sunflower is a very demanding plant and it can usually out
00:26:00
compete anything that it is planted with.
00:26:04
So sunflowers have very deep taproots.
00:26:08
I did a whole episode on sunflowers and their ability to
00:26:11
be able to. I guess it wasn't a whole
00:26:13
episode specific to sunflowers, but it was talking about phyto
00:26:16
remediation, which is the ability to be able to draw
00:26:19
toxins and other contaminants out of the soil.
00:26:23
Sunflowers are fantastic for that and if they have that
00:26:26
ability then you know they have a very, very strong root system.
00:26:31
So they are going to out compete just about anything.
00:26:33
The only thing that I have really seen them not be able to
00:26:36
handle at least in my area is a heavy growth of hemlock plant.
00:26:43
Like we have hemlock out here that is just invasive and goes
00:26:46
crazy. And I had tried planting
00:26:49
sunflowers to kind of out compete the hemlock and the
00:26:52
hemlock just it takes over every time.
00:26:54
So that's something that we have dealt with.
00:26:56
But sunflower great for suppressing weeds, especially
00:26:59
annual weeds, but you you may not want to plant any actual
00:27:02
harvestable crops anywhere near the base of them.
00:27:05
Now, sometimes a plant that we plant intending for it to help
00:27:12
can actually do the opposite. I'm all about experimenting with
00:27:17
companion plants to see what works and what doesn't work in
00:27:20
your garden in your experience. Again, we don't always have to
00:27:24
rely on these science research studies, et cetera, to show us
00:27:29
what works in our own garden. I just don't like to spread that
00:27:33
information to people once I see something works for me because
00:27:36
it may not work for somebody else if I just have anecdotal
00:27:39
information, right? But there are, you know, certain
00:27:42
cases where we know something doesn't work for very specific
00:27:46
reasons. For example, dill.
00:27:47
Dill attracts swallowtail caterpillars, which you know
00:27:52
actually it attacks this that tracks the butterfly and they
00:27:55
like to lay their eggs in the dill.
00:27:57
This also is in parsley as well, but dill specifically, and dill
00:28:03
also attracts aphids so you probably don't want to be
00:28:07
planting those near your tomatoes because you're
00:28:09
encouraging those caterpillars and you're encouraging aphids to
00:28:13
be in your tomatoes. Mature dill can also suppress
00:28:16
tomato growth first via that allelopathy early on.
00:28:20
So you know the early plants aren't so bad, but once they
00:28:23
start to go to flour then the dill can cause a problem.
00:28:27
So it's not usually a good idea to plant dill near your
00:28:30
tomatoes. Same thing goes with sunflowers.
00:28:34
Again, anywhere near beans. So, you know, I will plant
00:28:39
sunflowers along end rows in my garden.
00:28:42
It's usually the one thing that I don't plant in amongst
00:28:44
everything else. But if I'm going to plant beans,
00:28:47
they're going to be at the opposite end of that garden area
00:28:50
because sunflowers can actually attract stink bugs and they can
00:28:53
harbor seed maggots. And this is not something that
00:28:55
we want in our beans because beans are very susceptible to
00:28:57
the damage from those. They're great for pollinators,
00:28:59
the sunflowers are, but you just want to make sure that you're
00:29:02
monitoring them closely near any of those vulnerable crops.
00:29:06
Another one is fennel. Fennel also has allelopathic
00:29:10
compounds and it can inhibit the growth of a lot of vegetables,
00:29:14
most of them actually. So if you are growing fennel,
00:29:18
you likely want to plant it by itself.
00:29:21
And it's a great plant that you can put in a separate pollinator
00:29:25
bed and because it does again, attracts those things like
00:29:28
swallowtail butterflies. And so if you are growing fennel
00:29:31
as your crop to eat, then you want to keep it away from the
00:29:35
rest of your crops that it doesn't actually inhibit the
00:29:37
growth of the rest of your garden.
00:29:40
OK, so there are a few more plants that we may not want to
00:29:44
plant together just you know based on olelapathy or even just
00:29:50
direct competition. The first one is planting onions
00:29:54
or garlic in an amongst beans. So one of the things that we
00:29:58
get, one of the benefits that we get from planting beans or
00:30:01
anything else in the Allium or in the legume family, sorry, in
00:30:05
the legume family, is that beans and other legumes add nitrogen
00:30:10
to the soil through a symbiotic relationship with rhizobium
00:30:14
bacteria. These these bacteria form
00:30:18
nodules on the bean roots, so they convert atmospheric
00:30:23
nitrogen into a form that the plant can use through those
00:30:27
nodules. When the plant dies or when we
00:30:31
cut it down, we leave that root system in the ground, which
00:30:34
means those nodules are still in the soil.
00:30:37
And then as they decompose, they release that fixed nitrogen back
00:30:41
out into the soil. And that of course, helps enrich
00:30:44
the soil for future crops. If we plant onions or garlic,
00:30:49
any of our alliums next to our beans or near our legumes, it's
00:30:55
a bad idea because alliums release sulfur compounds and
00:31:00
Allison, which is an antibacterial compound.
00:31:03
And those compounds can actually kill off the beneficial nitrogen
00:31:08
fixing bacteria that are doing that job for us.
00:31:11
That's those are the bacteria that the legumes need for that
00:31:15
nitrogen fixing. So not only is that going to
00:31:18
affect the plants ability, the bean plants ability to be able
00:31:22
to kind of store up that nitrogen for us and give us
00:31:24
those benefits, but it actually may interfere with the bean
00:31:28
plants growth itself. So we want to avoid planting
00:31:32
onions or garlic in and around near our beans.
00:31:35
Another one would be carrots and dill or parsnip.
00:31:38
These are all in the APACA family and so they can cross
00:31:42
attract carrot flies and also attract the same diseases.
00:31:46
So we don't want to group them together.
00:31:50
The same thing goes basically for other plant families.
00:31:52
So nasturtiums, for example, nasturtiums will repel a lot of
00:31:56
different pests, but nasturtiums are in the brassica family.
00:32:00
And so it would be probably a bad idea to plant nasturtiums in
00:32:04
and amongst all of your brassicas because they're not
00:32:07
going to be very effective at the pests that we're worried
00:32:10
about in our brassicas, like the cabbage moths or other pests,
00:32:12
because the phytochemicals are all the same.
00:32:15
So This is why we generally don't want to plant things in
00:32:19
the same family all together. Same thing goes with like
00:32:22
potatoes and tomatoes. They're both in the nightshade
00:32:25
family, so they are both susceptible to the same fungal
00:32:28
and bacterial diseases, especially blight.
00:32:31
So we want to separate them to reduce that risk.
00:32:35
Does this mean that I'm not planting my brassicas all like
00:32:38
near each other? No, I'm still planting them in
00:32:42
beds that are close to each other because again, we talk
00:32:44
about this all the time. We're not farming on 1000 acres
00:32:47
here, right? And I mean, even I have more
00:32:50
room to plant than a lot of other people do.
00:32:52
But if you're gardening in your backyard, you only have a
00:32:55
limited amount of space. So you're obviously going to
00:32:57
have to be planting some of these plants close to each
00:32:59
other, right? So it's just important to,
00:33:02
again, use that companion planting to mix up all the
00:33:05
species. Tomatoes and corn, these are
00:33:08
both really heavy feeders and they're going to compete for
00:33:10
nutrients a lot of time. Plus corn can host the the corn
00:33:16
earworm, which is also known as a tomato fruit worm.
00:33:19
So that also targets tomatoes. We don't want those pests coming
00:33:24
in and landing on one and also being able to feed on the other.
00:33:27
So those can be, you know, both of the plants weak and it opens
00:33:30
them up to different pests and diseases.
00:33:32
So we don't want to plant those together either In terms of
00:33:36
companion planting with strategy, right?
00:33:39
This is where intercropping or interplanting comes into play.
00:33:43
We're going to talk next week about the strategies like really
00:33:47
dive deep into the kind of systematic version or way that
00:33:52
we can companion plant through intercropping.
00:33:55
It's based on timing, it's based on spacing, it's based on plant
00:33:59
architecture, all of these different things.
00:34:00
But some of the ones, you know, just here briefly that we can
00:34:03
touch on that are really good examples are things like what we
00:34:06
already talked about the three sisters, right, corn, beans and
00:34:09
squash. The beans fix the nitrogen the
00:34:12
corn provides support the squash suppresses the weeds.
00:34:15
And you can also deter like raccoons and stuff from getting
00:34:19
into your corn because the if you're using the squashes that
00:34:23
have like the spiky stems on them, that can actually help,
00:34:26
you know, keep those buggers from crawling in there and
00:34:28
trying to climb up the corn and and pull the corn down.
00:34:30
So lots of different benefits to each other when they're being
00:34:34
planted together, planting fast growing crops with slow growing
00:34:39
ones. So radishes or lettuce being
00:34:42
planted in between longer maturing crops like the broccoli
00:34:45
or your Peppers, not only is maximizing space, it's also
00:34:49
reducing that weed pressure. So those are good companions
00:34:52
together. But again, when we're talking
00:34:54
about deterring pests, we're mixing up those chemical signals
00:34:57
by planting multiple plant families together.
00:35:01
So that is deterring the pests because they can't find their
00:35:04
preferred host nearly as easily, especially, again, appropriate,
00:35:09
inappropriate landings. They land on a radish and go,
00:35:11
oop, that's not what I wanted. I want to land on the carrot and
00:35:14
then they might land on the carrot and then they land again
00:35:16
and oops, back on a radish again.
00:35:17
Like it's it it resets that whole cycle.
00:35:19
So the more things that we can plant together that are not in
00:35:22
the same plant family, the better off we are.
00:35:26
This kind of inter planting, you know, rows of of non host crops
00:35:31
not only visually confuses the pest, but it also, you know, can
00:35:37
confuse them in terms of like the texture and the landing on
00:35:39
them, right? So alternating rows of onions
00:35:41
and carrots that can mask each of those crops from their
00:35:43
respective pests like onion maggots and the carrot rust
00:35:46
flies, et cetera. This is why when I'm planting my
00:35:49
brassicas again, they are being planted near each other.
00:35:52
I might have one full bed that has all, you know, broccoli in
00:35:56
it. That bed right next to it may
00:35:58
also have cabbage in it. And then the one right next to
00:36:01
that might have cauliflower in it.
00:36:03
But they're not by themselves. They are not growing by
00:36:06
themselves ever in those beds. So even though those all attract
00:36:11
the same pests, I am inter planting those onions and those
00:36:16
lettuces and the the Elysium in and amongst them.
00:36:20
So it is still confusing those pests, right?
00:36:23
That is how you kind of get around the space issue when it
00:36:26
comes to growing your crops. If you can inter plant them and
00:36:31
confuse those pests, that's going to help.
00:36:34
To be most effective, we want to choose crops that have different
00:36:37
growth rates and that also have different canopy shapes and we
00:36:40
don't want to overcrowd. This is probably the most
00:36:44
difficult part of this and something we're going to kind of
00:36:46
deep dive into next week. Intercropping works best when
00:36:49
you have a plan and you understand the mature size of
00:36:55
these plants and how they're going to affect each other when
00:37:00
they are all at maturity, whether or not they've already
00:37:02
been pulled or not and that sort of thing.
00:37:04
So we'll go into that a little bit more next week.
00:37:09
Companion planting absolutely works, right, whether or not
00:37:15
we're using it in terms of, you know, increasing our soil health
00:37:19
or protecting our, our, our soil or keeping weeds at Bay or in
00:37:25
terms of pest management. But it works best as part of an
00:37:29
integrated pest management strategy.
00:37:32
I will link to the IPM episode that I did earlier in the
00:37:36
season. But this means prioritizing
00:37:39
plant health and soil health, right?
00:37:40
Because again, our healthy plants and our healthy soil are
00:37:43
going to be much better at resisting those pests and being
00:37:48
able to bounce back once they are predated on and on
00:37:51
monitoring for that pest presence and keeping track of
00:37:55
those lifestyles, life cycles so that we know when and how those
00:37:59
pests are operating. And then combining all of this
00:38:03
companion planting with using physical barriers and natural
00:38:06
predators when appropriate. Doing your homework on which
00:38:11
companions actually have evidence behind them is a really
00:38:15
good place to start. And is also going to sort of
00:38:19
weed out which ones might just be garden folklore.
00:38:24
A lot of plants do express insecticidal traits.
00:38:27
The key is to use them for your benefit and use them on plants
00:38:33
that are very dissimilar and that way they produce different
00:38:36
phytochemicals. So again that you know that
00:38:40
reference to the nasturtiums, they do repel pests, but they
00:38:43
are in the Brassica family. So maybe don't use them to try
00:38:46
to deter pests from others in that family.
00:38:49
Put them in with something else like maybe your squash plants.
00:38:53
And if you have, you know, or, or just use them as a trap crop,
00:38:57
if you have tried a companion planting combo that works for
00:39:01
you, there is no reason not to continue it if you know it's
00:39:05
working. And you can go ahead and share
00:39:07
that, you know, let me know. I would love to, you know, hear
00:39:10
some real world examples of things that have worked for you.
00:39:14
If you have tried a companion planting that totally flopped
00:39:18
and maybe you didn't realize why it flopped until later on or
00:39:22
even just now listening to this episode and realizing, oh,
00:39:27
nasturtiums attract aphids and I was trying to get rid of aphids
00:39:30
but I put them in and they were, oh, now I understand.
00:39:33
Go ahead and let me know that too.
00:39:35
I would love to hear about it again.
00:39:37
If I hear a bunch of real world examples from people, I am super
00:39:39
happy to, you know, update everybody in a future episode to
00:39:42
let them know like, hey, this has worked for some people,
00:39:45
maybe it'll work for you. Just remember, when you are
00:39:48
dealing with anecdotal companion plantings, what works for one
00:39:52
person may not work for another one.
00:39:54
So do not rely on any of these companion planting suggestions
00:39:59
as your sole way to keep insect pests at Bay in your garden.
00:40:04
Make sure it's part of an integrated plan and that you
00:40:07
have more than one way to keep away those pests.
00:40:10
Until next time, my gardening friends, keep on cultivating
00:40:12
that dream garden and we'll talk with you soon.