Subject: Re: Rotate Tomatoes?

From: [email-masked] (Jerry Heverly)
Date: 27 Feb 1995 22:56:42 -0800

Monique Ibey (ibeym@spock) wrote:
: Just trying to plan the layout/rotation schedule for this summer's veggie 
: garden.  I've read several books about companion planting and crop rotation.  
: Some say that tomatoes like to stay where they are.  Others suggest including 
: tomatoes in a yearly crop rotation.  Any advice from experienced tomato 
: growers out there would be appreciated.  I am in Zone 5b/6a (Southern Ontario) 
: according to my chart.

: Thanks in advance,

: Monique
	The main reason to rotate tomatoes is disease prevention.  
Several of the most virulent tomato pathogens are soil borne, i.e. the 
spores of the fungus travel through the soil and enter the plant through 
the roots.
	If you use disease resistant cultivars, often marked VFN on the 
label, you cut down on your chances of suffering one of these diseases, 
*but* the plant may be infected nonetheless.  The resistance 
characteristic prevents the plant from manifesting the disease but it can 
still be present.  You can innoculate the soil with the fungus without 
*this year* suffering from it.  The spores can remain in the soil and 
infect the crop in succeeding years.  You can also introduce diseases 
into the soil with other crops;  other solanaceous things like eggplant, 
peppers and potatoes; or other susceptible plants like strawberries.
	By rotating to another part of the garden you reduce your chances 
of suffering from these fungi.  Speaking from experience all it takes is 
one bad experience, one crop decimated by disease to get you on the 
rotation bandwagon.
Jerry Heverly, Instr. of hort, Diablo Valley College, Pleasant Hill, CA
-- 

Jerry Heverly, Oakland, CA

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From: [email-masked] ()
Date: 1 Mar 1995 15:53:31 GMT

Re: Crop rotation for tomatoes...

While I understand the need for crop rotation, I question whether it can be
done "properly" in the home garden setting.  When you're dealing with disease
that can be transmitted through the soil, is it possible to avoid trouble 
by simply moving the tomato patch to the other end of the garden?  Isn't it
true that something as simple as tilling the garden, or using the same hoe to
loosen up the soil at both ends of the garden can spread the diseases around?

I'm not saying that rotation is bad - for one thing, it allows for a more even
usage (nutrient-wise) of the soil - that is, it can prevent getting to a
point where certain patches in your garden have been nutrient depleted.
However, I wonder if rotating crops strictly for the sake of trying to avoid
certain soil borne diseases is really worth all the extra work?

just wondering,

- Tom

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From: [email-masked] (Christine Owens)
Date: 28 Feb 1995 10:55:10 GMT

Tomatos have about forty-million different diseases that will
over-winter in the soil.  Planting them in the same place every
year runs the risk of this year's plants picking up whatever
last year's left behind.  I have gotten the best results by rotating
their location so that there are two years between the time they
grow in any particular site.

Chris Owens

>
>Just trying to plan the layout/rotation schedule for this summer's veggie 
>garden.  I've read several books about companion planting and crop rotation.  
>Some say that tomatoes like to stay where they are.  Others suggest including 
>tomatoes in a yearly crop rotation.  Any advice from experienced tomato 
>growers out there would be appreciated.  I am in Zone 5b/6a (Southern Ontario) 
>according to my chart.
>
>Thanks in advance,
>
>Monique
>

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From: [email-masked] (Gerald Sacks)
Date: 1 MAR 95 14:21:17

In article <[email-masked]>, [email-masked] (Jerry Heverly) writes...

>spores of the fungus travel through the soil and enter the plant through 

I thought that preventing soil splash (by mulching) is an effective way to
prevent damage by verticillium and fusarium wilts.  Or are you talking about
other diseases?

>one bad experience, one crop decimated by disease to get you on the 

For those of us with small gardens, rotation is a pipe dream.  Does it
really matter in which part of my 80 square foot bed I plant the tomatoes?
Particularly if most of the rest of it has peppers and eggplants?

Gerald Sacks			[email-masked]

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From: [email-masked] (Natasha Elizabeth Dehn)
Date: 3 Mar 1995 00:21:26 GMT

David L. Martin ([email-masked]) wrote:
: I agree with the previous posts re: the need to rotate crops to lower
: chances of disease, and the preference for VFN type tomatoes if possible
: to improve the plants ability to tolerate disease:  note that the word is
: tolerate, not resist;  this means that the plant will grow ok, but the
: fruit will still carry it.  There is no such thing as resistance, and its
: almost impossible to relly rid the garden of diseases.
: Also bear in mind that ABSOLUTE CLEANLINESS is a must in fighting
: diseases.  This includes meticulously cleaning up all old tomatoe plant
: debris and NOT using tomato plants and tomatoes in the compost that will
: go into the gardens - this just reintroduces the diseases.
: The ground can theoretically be sterilized by covering it with black
: plastic sheeting for a year - the lack of air and extreme heat generated
: by the sun will presumably help - but you lose the garden for a year.

Agreed--in theory.  But if you're like me and have relatively few 
suitably warm and sunny places for tomatoes, you can probably get away 
with planting them in the same location again, as I have.  My grandmother 
has been planting the same small sunny patch for more than 40 years!  
Obviously there are no guarantees, but so far, so good.  In fact, the 
biggest problem I've run into is nutrient depletion.  Good compost 
resists disease and enriches soil: it will really help!  That said, if I 
could rotate tomatoes I probably would do so, on general good principles...

--Natasha Dehn

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From: [email-masked] (David L. Martin)
Date: Wed, 1 Mar 1995 15:15:16 GMT

I agree with the previous posts re: the need to rotate crops to lower
chances of disease, and the preference for VFN type tomatoes if possible
to improve the plants ability to tolerate disease:  note that the word is
tolerate, not resist;  this means that the plant will grow ok, but the
fruit will still carry it.  There is no such thing as resistance, and its
almost impossible to relly rid the garden of diseases.
Also bear in mind that ABSOLUTE CLEANLINESS is a must in fighting
diseases.  This includes meticulously cleaning up all old tomatoe plant
debris and NOT using tomato plants and tomatoes in the compost that will
go into the gardens - this just reintroduces the diseases.
The ground can theoretically be sterilized by covering it with black
plastic sheeting for a year - the lack of air and extreme heat generated
by the sun will presumably help - but you lose the garden for a year.

---

From: [email-masked] (Jerry Heverly)
Date: 2 Mar 1995 22:07:54 -0800

[email-masked] wrote:

: Re: Crop rotation for tomatoes...
: I wonder if rotating crops strictly for the sake of trying to avoid
: certain soil borne diseases is really worth all the extra work?

: just wondering,

: - Tom
	Nothing like a good question to make you realize how much you 
*don't* know about something.  This one sent me rushing to my reference 
books--without success *yet*.  My recollection from college days is that 
Verticillium and Fusarium (there are zillions of tomato fungi but, 
really, these are the most ubiquitous and the ones most worth discussing) 
live-over in the soil on old pieces of root material.  DuBose in his 
book(*The Total Tomato* says Vert "can live in the soil for up to three 
growing seasons".  Fusarium doesn't affect other Solanaceous plants.  I 
haven't been able to find out its degree of persistence in the soil.
	Westcott (*Westcott's Plant Disease Handbook*, the Bible of these 
sorts of books) says little on this issue.  "Do not transfer plants from 
areas where {Vert} wilt has appeared.  Do not set raspberries following 
potatoes or tomatoes; do not use tomatoes after eggplant or potatoes 
without long rotation."
	I plan to ask the leading plant pathologist in California about 
this next week but for now it seems to me that:
	a) even a minor location shift should lessen your chances of 
passing these two diseases from season to season.  You need to avoid the 
dead roots or other plant parts of previous crops.
	b) if you break your small garden into thirds that should do the 
trick if these disease do indeed last up to 3 years.
	c)  I'm as lazy as they come but this doesn't seem like excessive 
effort considering the risks.
	d)  after reading up on this I think I had fusarium last year.  
That part gets corn this year.
Jerry Heverly, Instr. of hort, Diablo Valley College, Pleasant Hill, CA
--

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From: [email-masked]
Date: 1 Mar 95 18:38:16 -0600

> Re: Crop rotation for tomatoes...
...> However, I wonder if rotating crops strictly for the sake of 
trying to avoid
> certain soil borne diseases is really worth all the extra work?

In my experience, yes, it is.  Particularly if you're trying to 
grow a crop that is just on the edge of being adapted to the growing
area.  Stressed plants are more susceptible to disease.

Another thing that seems to help is amending the soil with compost
and other organic matter.  This seems to result in soils that
are suppressive to several soil borne pathogens like Pythium.  Or
so the early research seems to indicate.

Kay Klier   [email-masked]

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From: [email-masked] (Sarah Turner)
Date: Sun, 5 Mar 1995 19:13:44 +0000

> Particularly if most of the rest of it has peppers and eggplants?

I get around this problem by growing vegetables from different
families in successive years.  For example, last year I grew brassicas
(including radishes) and legumes; this year I intend to grow cucurbits
(or is it curcubits?  :-), beetroot, lettuce, salsify and tomatoes in
my small garden.  Since I particularly love growing tomatoes, I grow
them every year in grow-bags against the wall of the house.  I buy new
grow-bags every year, and dig the peat from the old grow-bags into the
soil IF I'm not going to be growing tomatoes in the soil that year.

Sarah
-- 
Sarah Turner
[email-masked]