Bottom rot on my tomatoes...

 

I'm in Southern Ontario Zone 5b (Niagara escarpment)

I have tomatoes in pots, two plants per pot, staked.  Pots are 12" x 12" x
12" deep.  A bit of a gravel bed on the bottom, maybe 3/4" thick.   They
face south and get 7 hours of sun a day.  Soil is triple mix topsoil with
1/3 peat moss, and drainage holes at bottom of pots.  These plants were
planted by children in a school then we inherited the plants when school was
out for summer.  They flowered nice.

The bottoms of some of the tomatoes have gone black.  A quick Google search
suggests this is prolly due to lack of calcium but we have 25 hardness hard
water.  Our garden water is not run thru the water softener.

How can I determine if it's calcium defiency or not?  What other
possibilities can this be?  The leaves never wilt and growth and foliage
seem healthy.  No bugs are eating the leaves.  I've never grown tomotes
before.  Our herb gardens and flower beds are fantastic and are watered at
the same intervals as our tomatoes.

If somebody wants pictures I can through up on the net if so.

 



http://ipm.illinois.edu/diseases/series900/rpd906/index.html

Predisposing Factors
Conditions favoring blossom-end rot also favor noninfectious leaf roll.
Blossom-end rot is most common when there are: 1) prolonged dry periods;
2) frequent or heavy rains followed by an extended period of dry
weather; 3) soil conditions unfavorable for uptake of calcium; 4)
excessive soil salinity; and, 4) root damage from infectious diseases.
Other factors favoring blossom-end rot include early planting in cold
soils, poor fruit setting, and high temperatures. Any condition that
reduces the ability of the roots to absorb water and, hence, soluble
calcium salts predisposes the plant to blossom-end rot. Some factors
that could affect the roots are root-rotting fungi, nematodes,
underwatering, overfertilizing, root pruning due to cultivation or
insect feeding, and lack of aeration due to soil compaction or
overwatering. Losses from blossom-end rot increase when the soil
contains an excess of total soluble salts in relation to soluble calcium
salts. An excess of soluble ammonium, potassium, magnesium, or sodium
salts reduces calcium uptake by the plant. Blossom end rot is rarely a
problem in soils where calcium is available in proper balance with other
available nutrients. Sometimes rapid luxuriant plant growth accentuates
development of the disorder, because the new growth draws heavily on the
available supply of calcium in the soil. Calcium is not translocated
within the plant from older to younger tissues. Therefore, injury may
appear on the blossom end of the young fruit, which is especially
sensitive to a lack of calcium.

Some tomato varieties are much more susceptible to blossom-end rot than
others (see Table 1).

--> **Generally, elongated pear and plum tomatoes used for processing
and canning are prone to this disorder.**<--

Table 1: Incidence of some tomato varieties to blossom-end rot grown at
the Dixon Springs Agricultural Center under irrigation.

Low Incidence                           High Incidence
 
Losses less than 10% in severe years    Losses of 15 to 30% or
                                        more in severe years
 
Celebrity                               Big Boy
Fresh Pak                               Castle King
Jet Star                                Fantastic
Manapal                                 Independence
Mountain Pride                          Supersonic
Pik Red                                 Surprise
Sunny                                   Whopper
Winter                                  Wonder Boy

As you can see, "blossom end rot" isn't that uncommon. Often gardeners
will have trouble with it at the beginning of ripe fruit production, but
then it usually goes away on its own.
--
- Billy
"Fascism should more properly be called corporatism because it is the
merger of state and corporate power." - Benito Mussolini.
http://www.democracynow.org/2010/7/2/maude
http://www.democracynow.org/2010/6/28/naomi_klein_the_real_crime_scene

 

The Henchman wrote:

Blossom end rot is a complex problem.  Some highly qualified authorities are
not sure exactly how it happens although they seem to agree it is related to
calcium nutrition.  There was a long thread on this at rec.gardens a week or
two ago.  To summarise:

-  BER is an issue with calcium mobility which occurs most often when the
plants are young and growing quickly.  It often goes away without
intervention as the plants mature.
-  It can be caused by lack of calcium in the soil or uneven watering which
can interfere with nutrient mobility.
-  Some cultivars are more susceptible to it than others.
-  If adding lime to supply calcium do not overdose as this may raise the pH
too far which will cause other nutrition problems.

David

 



Please allow me to obscure this explanation.

<http://aob.oxfordjournals.org/cgi/content/full/95/4/571>
"The symptoms, occurrence and search for the cause of blossom-end rot
(BER) in tomato (Lycopersicon esculentum) have been described frequently
in the scientific literature of the last century (see Brooks, 1914;
Spurr, 1959; Saure, 2001). The majority of studies have identified a
local Ca deficiency in the distal fruit tissue as the primary cause of
BER (Lyon et al., 1942; Ward, 1973; Bradfield and Guttridge, 1984; Adams
and Ho, 1992). For this reason, BER was considered to be a symptom of a
Ca-related physiological disorder (see Shear, 1975; Bangerth, 1979;
Kinet and Peet, 1997). However, the induction of BER in modern
glasshouse tomato production is rarely caused by insufficient Ca in the
feed. More often, BER occurs in plants with an adequate Ca supply when
grown under conditions that either (a) reduce the transport of Ca to
rapidly growing distal fruit tissue or (b) increase the demand of the
distal fruit tissue for Ca by accelerating fruit expansion (Ho, 1998b).
In practice, BER can be prevented by increasing Ca transport toward the
fruit by reducing canopy transpiration (Li et al., 2001) or by canopy Ca
sprays (Geraldson, 1957; Wilcox et al., 1973; Wada et al., 1996; Ho,
1998a; Schmitz-Eiberger et al., 2002). Nevertheless, since BER may occur
in plants and fruits with apparently adequate tissue Ca concentrations,
predicting and preventing the occurrence of BER in glasshouse tomatoes
from measurements of their Ca status has not always been effective.

---> This has led to a recent opinion that Ca nutrition is neither a
primary, nor an independent factor in the development of BER (Saure,
2001)."<---            
                  (arrows added for emphasis)

Other than that, David has given you the working theory of BER. Paste
(plum) tomatoes seem to be the most susceptible, and most BER will
diminish in severity, or go away altogether with a little time.
--
- Billy
"Fascism should more properly be called corporatism because it is the
merger of state and corporate power." - Benito Mussolini.
http://www.democracynow.org/2010/7/2/maude
http://www.democracynow.org/2010/6/28/naomi_klein_the_real_crime_scene

 





When you say go away, do you mean leave well enuf alone and it'll grow out
of this phase?

Is there a difference between municipal groundwater ( hard water from
limestone sources) and rainwater used for watering fruits and vegetable
plants?