This companion planting may actually work!

anney(Georgia 8)June 25, 2010

I am not a big fan of companion planting, since too many times it just doesn't work to do what is claimed, despite all the internet sites making unfounded and unscientific claims.

But sometimes it does. This link explains that the sense of smell among insects is "very sharp" and is used by insects to find their favorite plant treats but can also be used to repel some insects from their favorite plants.

However, insects are not attracted to plants just because of their emitted odors but by color as well, and that includes UV colors that human beings cannot see. Maybe the trick is to confuse the insects so the introduced plant odors drown out the visual attraction -- then the insect pests can go elsewhere if you provide other attractive plants that you wouldn't mind if they're on.

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They say the corn plant hides the squash plants from the squash vine borer, don't know. It does seem to be out of sight out of mind. It's nice to know an effort is truly being made. I've seen more of the attracting predators of the unwanted bug more than I've seen companion plants getting rid of them.

There has to be something to it, but at infestation levels, nothing is going to work.

    Bookmark   June 25, 2010 at 9:40AM
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instar8(Z 5 N.IN)

Hmmm...wonder if the marigolds need to be blooming? Wonder if you could spray marigold extract on the crucifers...? Wonder if onions attract cabbage moths even if they AREN'T blooming?

Can you guess I'm getting eaten up by cabbage worms AND I have onions interplanted with my whole cole collection??? Yeesh...BTW, this site has french marigold seeds $3.50 /1000.

BTW I'd rather pick worms than do BT, i have butterfly borders all around my garden.

Here is a link that might be useful: cheap seeds @amazon

    Bookmark   June 25, 2010 at 11:07AM
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susan2010(6 Massachusetts)

I have to confess that I don't worry about bugs much. Sure they chomp on some of my plants, and I'm sure that if I had an ovewhelming infestation of some pest I'd be upset and probably look for a solution, but for the most part I've found that if my garden is healthy and my plants robust, bugs don't do a whole lot of damage. One thing I will say is that since I feed birds, I have a LOT of them in my yard, and they may do a good job of keeping things from tipping over to the point where I'd have to consider spraying something.

And, of course, I garden for fun, not to feed myself (that's a wonderful bonus), so I can "afford" to be casual about it.

    Bookmark   June 25, 2010 at 11:15AM
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makete(U.P. of Mi.)

I take it you have never had potato bugs devastate your whole crop. I just hate those things, and they have killed my whole seasons worth of potatoes or atleast knocked them back so hard, that we hardly got anything.

    Bookmark   June 25, 2010 at 11:34AM
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anney(Georgia 8)


I suppose many of us gardeners do it for fun, though it's interwoven with other things, too. I garden to actually feed my family year round if possible (freezing extra vegetables), so when people with the same needs are inundated with insect pests, we're always looking for ways to deal with them.

    Bookmark   June 25, 2010 at 11:47AM
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jimster(z7a MA)

Anney, your first link doesn't work. I'm curious to seed what it says.

I'm always interested in the well researched info you post. Too much speculation and wishful thinking is posted as fact.


    Bookmark   June 25, 2010 at 12:36PM
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anney(Georgia 8)


Sorry! I keep these links in an Excel file, and they all seem to insert a break symbol that messes up the link if I don't notice it. Maybe the one below will work.

Here is a link that might be useful: Mainstay of Organic Pest Control Won't Deter Colorado Potato Beetles

    Bookmark   June 25, 2010 at 1:36PM
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I'm with Susie on the birds. Although I don't really feed them, my garden has enough trees around it that my yard is always loud with birds singing =) I was worried about Colorado potato beetles as I'd seen a bunch on my plants, and even started seeing a few larvae (despite some pathetic attempts at hand-picking), and then suddenly within about a week they were all GONE--adults, larvae, and all. I think the birds must have eaten them all. I don't mind paying them in some lost strawberries!

    Bookmark   June 26, 2010 at 11:49AM
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We have lots of trellises, poles and other perches, which the wild birds use to hunt for things that move in the garden. On a 25-foot row of potatoes, I have found two CBP adults and three larvae this year, only one last year. Has to be the birds.

    Bookmark   June 27, 2010 at 11:39AM
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cabrita(9b SoCal)

I think it works sometimes. I take companion planting under a larger umbrella, with a fuzzy boundary between companion planting and inter cropping.

Anney the first article on the CPB was very interesting, and it makes me glad I don't have this pest. I don't seem to have the squash vine borers either. However, I have pests that are not covered under the two best known books on companion planting that I have: 'Carrots love tomatoes' by Louise Riotte, and 'Great garden companions' by Sally Cunningham. I like using some of the principles explained in the last book, however, it is for a very different climate than mine. They do not have stink bugs and harlequin bugs in New York, and I cannot grow some of the herbs/flowers she recommends in southern California. I do not think she can grow chayote or artichokes, and I cannot grow parsnips or cherry trees. So even though I recommend both books, you might find yourself like me, following the same plot line but changing the characters.

I see different scenarios in companion planting:

-plant something that will attract pollinators (then you get more cukes and squashes, and other fruit). That one is a no brainer. Some details in this though are to plant the type of pollinator attractors so flowering happens when you need it. If your citrus flowers in the spring, it is not going to help your chayote in the fall (change your characters according to your zone here).

-plant crops that will be compatible so you can harvest more out of your land and eat more (buy less of those flavorless grocery store vegetables). The tomatoes and carrots fall under this strategy for me. The carrots will 'fit' under the tomato canopy and be protected from sun that is too harsh during peak tomato season. They will get less light than ideal and the carrots will be skinny, but I can still get carrots. How about peas and tomatoes? I use tomato cages and plant bush peas on the outside. The peas like the cages. When they are about to produce, or at some time along their life, I plant baby tomatoes inside the cage. The peas shield the tomatoes from wind and too much sun, so the seedlings are somewhat protected. By the time they need their own space the peas are gone.

-plant something that will attract a beneficial that will eat a bad guy eating your plants. I get aphids on my favas and on my artichokes sometimes. I plant cilantro and other lady bug attracting plants near them. I have lady bugs on everything that tends to attract aphids. I know I have aphids too (what would they be eating?) but they are under control. I only get aphids on the artichokes after they are done, and I get no aphid damage on the favas. I get some stink bug damage to favas so I lose about 10% to them. I accept 10% loss on any crop as cost of doing business.

-Divide and conquer. I can grow some crops problem free, so I can bunch them (tomatoes, carrots, beans, potatoes, artichokes). Cole crops are another story. The Brassica olearacea family in particular. Kale, collards are not too hard. Broccoli, gai lan, cauliflowers, brussels sprouts are harder. So I plant those in different beds. I just surround them with other plants in different families. I just surround them with legumes, herbs, carrots, beets...Not perfect and totally pest free, but it certainly works better. This way, you could get infestation in one, but not all, which certainly will happen with monocropping. We just ate some very nice and large cauliflowers - almost pest free.

-Surround your plants by some herb/flower that repels your pests. Supposedly, epazote and mints will repel the ants that farm aphids on your artichokes, favas, cowpeas. This did work on one of my artichokes, now I have to get rid of the mint around it (not a problem for me) so you have side effects to your companion remedies sometimes. One of my cauliflowers was surrounded by oregano, I did not get a single aphid on it, while the one farther away (oregano free) did have some aphids (sprayed with water and brought in some lady bugs). The one surrounded by oregano did not even need anything done though. Doing nothing at all is even better than a gentle bio-friendly spray/remedy. However, oregano is a thug in the garden, and now I have to harvest aggressively. (Hot oregano tea baths, anyone?)

OK, there is more but I have to go weed and plant okra. I did not mean to write an essay.

I suppose I should mention I use no chemical pesticide (maybe it is obvious already?). I avoid neem oil as well because my neighbor raises bees. I do feed ourselves from the garden (veggies and fruits for two people and 4 little dogs).

    Bookmark   June 27, 2010 at 2:20PM
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jimster(z7a MA)

One of the principles of companion planting is puzzling me.

Pollinators are selective in which plants they visit. That is clear enough if you observe the insects in your garden when plants are in bloom. Bumble bees, for example will pollinate tomatoes (by buzz pollination or sonication) while honey bees will ignore them. Why is it necessary to plant crops of a different type than the the desired crop to attract pollinators? Isn't the crop itself sufficient to attract its pollinators?


    Bookmark   June 27, 2010 at 6:19PM
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cabrita(9b SoCal)

>> 'Why is it necessary to plant crops of a different type than the the desired crop to attract pollinators? Isn't the crop itself sufficient to attract its pollinators?'

I wish I knew. Perhaps someone more knowledgeable on insect behavior or bees specifically will add a post.

I can just tell you some observations I made last fall. I was a little concerned about the chayote flowers getting pollinated, since they bloom in very late fall (Nov and Dec here). They are in the squash family but not the squash genus, so I thought they needed pollinating action to reproduce(No sure if this is true or not). There are less bees in the late fall, and less flowering plants in general.

I saw a lone bee there an afternoon, it stayed quite a while. Two days later, the reports were that it had told its friends, and the whole chayote canopy was covered with bees. Obviously chayote is a good crop to feed the winter crew of bees, but going back to your question, was there something else flowering in the garden that attracted that first explorer lone bee? would it had found the chayote without other flowers?

Going back to other 'tricks' on companion planting, I wanted to add another one:

-use the companions as trap crops. This means you think the pests will find the traps tastier, so they will eat them and leave the crops that you prefer eating mostly intact. Radishes and mustards can be used to protect brassicas (even though I still prefer separating them, or maybe use both strategies). Mustard seeds are very cheap is you buy it as a bulk spice (brown or yellow, yes they will sprout), and radishes might get their leaves eaten, but the root will still be OK. Sometimes you have to guess what would they prefer eating? Sunflower seems to be preferred over many things, so I plant lots of them. My pests include squirrels, as well the stinkbugs and harlequins. Not sure if I can get the green stink bugs to favor the sunflowers over okra, I will try it this year if it ever gets warm around here. Nasturtiums also seem to act as trap crops for aphids I have noticed. In any case, I cannot find predators for the harlequins (they make themselves taste bad to birds by absorbing some of the cole plant compounds). Therefore, if something is prone to get eaten by them, this is the only non chemical option that I see available. Grow something else nearby that hopefully they will like even better.

So yes, it works, but it does not work for everything and sometimes you sort of pay a price for it working. I still rather have invasive mint and oregano, and sow a few mustard and sunflower seeds for the pests than ...some of the other non-biological solutions.

    Bookmark   June 28, 2010 at 2:29PM
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I think it probably has to do with achieving a sufficient level of stimulus, so that the stimulus (airborne chemicals and/or visual depending on the pollinator) is strong enough to be detected by insects in the vicinity.

Often a home veggie garden has a small number of many different plants, rather than large numbers of, say, squash or tomatoes. Often the number of blooms in the garden at one time is quite small.

Also, veggies have been selected by us for their food/cultivation qualities, not necessarily attractiveness to pollinators. It may be that the common flowers that are recommended for bringing pollinators into the garden are ones that supply a particularly strong or preferred odour/shape/colour.

Just my thoughts.

    Bookmark   June 28, 2010 at 6:23PM
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Anney, it makes for an interesting discussion topic!

I wish I could find a thesis that I read several years ago on companion planting. The conclusion seemed very simple: one species gain some benefit, the other species is not seriously inconvenienced.

Cabrita, you are very observant and attentive in your garden and you have introduced some very clear and good ideas on this subject. However, I'm having some problem with the last one. I really don't like the idea of trap crops unless the gardener intends to destroy the pests on those plants.

There have been a few adult Colorado Potato Beetles around my gardens and causing some problems. I suppose that they have overwintered - the first one I saw was about 6 weeks back, in the spring.

Right now, I'm pulling weeds and the nightshade has shown up. It is a common weed in the cultivated fields near my garden and the birds like to sow the seeds. The small nightshade plants are covered with tiny CPB larva! Some of those plants will be shredded by the time I've located all of those weeds and CPB's in my garden. Where can I expect those bugs to show up next? I can't help but think it will be on the tomatoes, potatoes, and eggplants.

Bird companions? I think about the best idea I've had is to grow sunflowers with the vegetables! The flowers are visited regularly by finches, chickadees, and chipping sparrows long before any seed has matured. These birds while nesting are death to many insect pests!

I don't suggest bird feeders amongst the veggies because of all the bird droppings but planting some sunflowers (and allowing a few to mature in the fall) seems an awfully good idea.

But, see how "So yes, it works, but . . . sometimes you sort of pay a price for it working" when it comes to birds? They attack the caterpillars but spread nightshade seed around the garden while doing so . . . ! Ah well, all a part of gardening life.


    Bookmark   June 28, 2010 at 7:17PM
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jimster(z7a MA)

The idea that trap crops which are more attractive than the main crop and will distract them from the main crop is counter to the idea that a secondary crop attractive to pollinators will help pollination of the main crop. That is a mouthful. Do you see my point? I'm saying that, if a trap crop will draw insects away from the main crop, then a crop to attract pollinators will draw pollinators away from the main crop, won't it?

Ausbirch does make a good point about low density of garden crops and level of stimulus. It is supported by Cabrita's observations.

Steve supports the use of trap crops to concentrate pests and then destroy them, not just depend on the trap crop as a distraction from the main crop. I agree.

I'm not much of an ornithologist, but I think seed eating birds usually don't eat insects. Is that right? To attract insect eating birds, maybe bird baths are useful. Or structures which provide places to perch.


    Bookmark   July 2, 2010 at 4:51PM
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gjcore(zone 5 Aurora Co)

Companion planting is more of an art than a science. Play with it a bit and see what works for YOU.

One students failed experiment does not exactly impress me that it didn't work for her.

    Bookmark   July 2, 2010 at 7:47PM
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Posted by jimster. . . I think seed eating birds usually don't eat insects. Is that right? To attract insect eating birds, maybe bird baths are useful. Or structures which provide places to perch.


I bet you are right about the birdbaths. People who have them seem to do a lot of complaining about keeping them clean, however. I'm thinking about a "bird watering station" in my future!

My friend, the Chickadee! "Diet: Black-capped Chickadees eat large quantities of insect eggs, larvae and pupae (insects in the torpid stage), weevils, lice, sawflies, and other insects. They also feed on centipedes, snails, slugs, and spiders. The chickadee is one of the most important pest exterminators of the orchard or forest.

"They consume some berries and seeds, especially in the winter when insects become scarce. They are commonly seen at bird feeders." (link below)

Give them sunflowers.


Here is a link that might be useful: Black-capped Chickadee

    Bookmark   July 2, 2010 at 8:35PM
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I'm saying that, if a trap crop will draw insects away from the main crop, then a crop to attract pollinators will draw pollinators away from the main crop, won't it?

Your reasoning is spot on, Jim. There is always the risk that pollinators will come for the flowers and ignore the veg. I've certainly seen that in my own garden - bees all over the marjoram and not anywhere else.

I see it like this. Just as a trap crop will not (IME) attract all of the whatever pest it is off the vegetable target, so it is that if you use an attractor plant to get pollinators into the close vicinity of the garden, some of the pollinators will visit the vegetables. If the alternative is that pollinators will not even find the garden, that's a win for the gardener.

I bet there are some exceptions to this (I recall reading something about bees being distracted away from strawberries by some flower) but it makes sense to me as a general rule.

And since very few commonly grown veg species are insect-pollinated, my interest is purely academic. I mingle veg and flowers for pest control and aesthetics, not for pollination. But I'm sure if I was growing 40 acres of strawberries or cucurbits I'd care more ; )


    Bookmark   July 2, 2010 at 10:37PM
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This is just my own thoughts, but it seems like many pests (like aphids) prefer to settle down on a plant and devour it rather than grazing from plant to plant... so trap crops can work reasonably well. On the other hand, pollinators like bees are constantly moving and therefore likely to hit a lot of plants at a shot, including the vegetables.

I like planting flowers in my garden because they tend to get a LOT more blooms at a time than the vegetables, and hold them more prominently on the stems, so they're really good for attracting the bees in the first place. And it seems like the early bloomers get the bees coming early, before my squash (for example) are flowering. So by the time the squash is in bloom, I already have a regular population of pollinating insects visiting.

Just my own observations...

    Bookmark   July 3, 2010 at 4:20PM
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