Yep, that's what I've read as well. Planted cheek by jowl to make nematodes howl. ;-)

tj

first.. you are in OH .... why are you dealing with NC???? that cow palace OSU ought to have info for you ... lol

regardless.. you would NOT buy and plant PLANTS... too much $$$$

you would buy bulk seed.. and germinate a ground cover ...

ken

We most definitely do have root-knot nematode in Ohio, Ken. LOL at calling OSU a cow palace. I studied Hort there, and I've heard Columbus called a big cow-town before, but when we come up from the sticks to the big city, they think of themselves are cosmopolitan. Yes, it takes a big bunch of marigold to combat them, but the preferred treatment is crop rotation. If you leave the ground fallow for three years or plant species they don't parasitise, you can presume the soil is free of them and return to your normal crop.

We most definitely do have root-knot nematode in Ohio, Ken. LOL at calling OSU a cow palace. I studied Hort there, and I've heard Columbus called a big cow-town before, but when we come up from the sticks to the big city, they think of themselves are cosmopolitan. Yes, it takes a big bunch of marigold to combat them, but the preferred treatment is crop rotation. If you leave the ground fallow for three years or plant species they don't parasitise, you can presume the soil is free of them and return to your normal crop.

I always wondered how folks got double postings, and it happened to me. It's those dang ads hanging and timing the page out.

Well, even with years of fallow or tolerant plants, you're still likely to have nematodes in the soil. They'll be at lower than previous numbers but will start rebuilding their populations as soon as you plant a susceptible crop.

When the marigolds are used, the nematodes will infest the roots but won't be able to multiply. The marigold planting must be for an entire season with no other plants in the affected area.

The common notion that one can interplant marigolds to prevent, or limit, RKN infestions is nonsense.

Jean
who gardened for 30-some years in SoCal, all the while dealing with plant damaging RKNs.

Ken--who said anything about buying marigold plants? I rarely have even bought marigold seeds in my life; they are best snithered from a friend or neighbor or even a street planting. :-) I plant them just for the spots of color and to bring in the odd pollinator among the veggies.

And I am not "dealing with" NC (or RKNs). Happened to Google RKNs (cannot now even recall why; maybe I just happened across the NC website en route to something else). Just was struck by the vision of 300 marigold plants in 100 sq ft... Surely none of them would be very vigorous.

Much of what I read in that article I learned back in the 1970's, some cultivars of Marigold can help control some nematodes. Like other things in your garden you may not want total control of nematodes since some are beneficial and some are even predators.

Here is a link that might be useful: About Nematodes

The beneficial nematodes will not be affected by marigolds, kimmsr. Only the plant parasitic species.

That, Rhizo, implies that the substance in the Marigold roots that controls the nematodes can distinguish between good and bad nematodes just as some people seem to think that certain pesticides can distinguish between insect pests and beneficials. It just does not happen that way.

I'm very interested in your theory, kimmsr. Please link some data that supports it....I would sincerely be appreciative. Will look forward to it.

One thing that hasn't been mentioned as yet is that a soil test (nematode assay) should come first. Not all plant parasitic species will be effected by marigolds. Contact your local extension for information on this specialized test. There are several different RK species, for example....not all are susceptible to marigold's chemistry.

Once the inventory has been done, you'll be better prepared to match up the right marigold.