Re: [tomato] light, not heat

margaret lauterbach (
Thu, 04 Mar 1999 10:41:58 -0700

At 09:20 AM 3/4/99 -0800, you wrote:
>-----Original Message-----
>From: margaret lauterbach <>
>To: <>
>Date: Thursday, March 04, 1999 7:49 AM
>Subject: [tomato] light, not heat
>Thanks Margaret for this information.
>>"The bottom line, say mycorrhizal researchers, is that if you already have
>>healthy soil that contains a lot of beneficial microorganisms, you probably
>>won't derive much benefit from mycorrhizal inoculants.  If you have just
>>moved to a new development where the topsoil was replaced with fill dirt
>>and construction debris, mycorrhizae may be beneficial if used in a program
>>of organic soil amendments and if use of pesticides and quick-release
>>synthetic fertilizers is kept to a minimum....
>Researcher Dr. Robert Linderman and others have spent a great deal of time
>studying Easter lilies on the southern Oregon/northern California coast.  He
>found that cultivation and phosphate (super phosphate) suppressed
>mycorrhiza.   There is evidence that different species of fungi produce
>different responses.  Most commercial innoculants provide combinations of
>different species for just that reason.   What I have in my home garden may
>or may not be the most benificial.  Also, I want the mycorrhizal established
>on the roots even before I transplant my plants into the garden.  (Timing
>obviously makes a difference re the direct seeding posts)  The mycorrhizal
>relationship takes about two weeks to become established.  We usually see
>the results of fertilizing in an additional two weeks (unless we use foliar
>applications...which make a much more rapid response).
>"(Michael) Miller of Argonne National Laboratory says, 'Under most
>>gardening conditions, you have mycorrhizal fungi already present in the
>>soil.  You have to have the appropriate fungi to get the optimum response
>>from different host plants.  Unfortunately, with most commercial
>>inoculants, you don't know if it's going to work...."
>Yes, most soils have mycorrhizal fungi present.  Are the most benificial
>species present?  Commercial innoculants usually contain species that have
>proven valuable in tests.  There are regional differences and differences
>even in one's own gardening area in the species of mycorrhiza present.
>I might also be well to remember that unless there is big money behind a
>product...whether it is vitamins, medicine, or in this case 'home garden use
>of mycorrhiza' it is not going to get the funding to do the tests.  Somehow
>I don't believe my 17 tomato plants are high on any researcher's list!
>Then too I believe that for a couple of dollars I am willing to see if using
>innoculant make a difference on my soil and plants.  That is the ultimate
>test.  Either I choose to try the innoculant or I don't.  At least now I can
>make that choice...five years ago I couldn't (as the product was available
>An interesting research report, beyond 'will my tomatoes do better' is
>and also
>Louis Mensing
>Eugene, OR

One thing I did not quote was: "Not all the products that are on the market
are equal. The key to successful production of mycorrhizal inoculants is
avoiding contamination with fungal pathogens -- such as Phytophthora spp.,
which cause root rot  -- says Elaine Ingham, who runs Soil Foodweb, Inc.,
in Corvallis, Oregon, a company that tests soil for the presence of
microorganisms.  Ingham suggests asking suppliers howw they produce their
inoculants.  'If they are just going out and extracting spores from soils,
they are likely to end up with pathogens,' she warns.  (Don) Chapman says
reputable producers of mycorrhizal inoculants will list the fungal species
used in the product and provide certification of the viable spore count...."

It may benefit you and others, but I do not intend to use purchased
inoculants.  Since my tomatoes have been growing in the same location for
nearly 30 years and have been organically fertilized, they should have
created their own mycorrhizae.  The one change I'm going to make is to stop
annual rototilling of that area.  Margaret