Soil Preparation Course: To Prevent Blossom End Rot (BER)

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UNIT 1: The Definition and Etiology of BER

Content
Blossom-End Rot (BER) is a physiological disorder, not a disease, affecting the quantity of fruit and affecting the quality of fruit. It is a calcium disorder of vine and tomato cells, with symptoms especially occurring in fruit cells. These cell walls collapse and die.

Signs and Symptoms

BER forms at the blossom end of the fruit, away from the vine attachment.

BER occurs in young fruit or in ripened fruit. First sign appears as a dark, water spot on the fruit (see green fruit toward the right).

At it's earliest stage the lesion may be cut away and the remaining fruit is edible.  The second stage is brown and leathery.

As it progresses, opportunistic organisms further attack the lesion (presenting a black mold) and the remaining fruit becomes inedible.

The etiology of BER is a calcium deficiency. This calcium deficiency occurs in (1) the soil preparation phase or (2) the care-and-maintenance phase of horticulture. Thus we group BER as 'soil-preparation-related BER" and 'care-and-maintenance-related BER'.

Once BER is recognized (at the fruit production stage) the soil cannot be altered. Alteration would further disturb deficient root structures. The only method of treating 'soil-related BER' is to prevent the calcium deficiency during soil preparation, by balancing the soil contents.

UNIT 2: Regarding the Quick Guide

Content
For this course memorization is not needed! You may answer any question using notes in an 'open-book' fashion! In fact a Quick Guide is offered as a 'cheat sheet' for this course and for each spring season. Link to the Quick Guide and print a copy to use with this lesson and to use during each soil preparation season.

There are three sets of soil properties that need addressing to balance tomato soil. These three properties are:

Physical Properties
(the particles) Chemical Properties
(the nutrients) Nutritional Properties
(the pH level)

For each of these soil properties, tomato gardeners must ask the following questions to scientifically gain balanced soil.

What is physically balanced soil?
What is chemically balanced soil?
What is nutritionally balanced soil?

How does physically unbalanced soil affect tomatoes?
How does chemically unbalanced soil affect tomatoes?
How does nutritionally unbalanced soil affect tomatoes?

How do I perform a physical test?
How do I perform a chemical test?
How do I perform a nutritional test?

How do I treat soil to obtain physical balance?
How do I treat soil to obtain chemical balance?
How do I treat soil to obtain nutritional balance?

We will study the first two of these properties, the physical and chemical, answering the questions above. For both of these properties there are home soil tests available for testing your own tomato soil. The third property, the nutritional, requires professional soil testing   It will be covered in another course.

Notice that directly below the properties Physical, Nutritional and Chemical that the informal names appear. During the remainder of the course, rather than using the formal names, we will refer to these properties as soil "particles", soil "pH" and soil "nutrients" (pronounced P. H.).

The Quick Guide is a summary of these properties and these questions. In the spring when gardeners ask questions such as, "Which soil tests do I need before I plant?," the Quick Guide will be a good reference to answer these questions.

UNIT 3: Soil Particles

Content
What is balanced particle soil?

Physical (particle) soil structures include measurements of clay, sand and silt. Particle balance is important for plant calcium uptake. A combined ratio too high in clay may hold water and stress roots, contributing to BER. A ratio that is too high in sand may often allow too much water to drain away from the roots, carrying important nutrients away as it drains.

Generally an ideal ratio for quality tomato soil is 20% clay, 40% silt and 40% sand. Physical soil needs differs in many areas of the United States, for instance in coastal areas soil moisture rate differs from other US areas. It is important to consult your state agriculture extension for physical soil information pertaining to your growing area.

Content

Percent

Fraction

Ratio

Clay

20 %

1 / 5

1

Silt

40 %

2 / 5

2

Sand

40 %

2 / 5

2

In studying the above chart for ideal physical soil content, the first readings are listed in percents. Notice that the percent column equals 100%.

If we were to write the 20% as a fraction, the 20% equals 1/5. The 40% equals 2/5. Notice the fraction column. These fractions equal 5/5.

If we were to write these as a combined ratio, the ratio is one part (clay) to two parts (silt) to two parts (sand). It is often written 1:2:2 or 1-2-2.

If we were to stack these sections of soil in a mayonnaise jar, the clay would be half as tall as the silt and also half as tall as the sand.

How do unbalanced soil particles affect tomatoes?
A physical imbalance of clay, sand and silt prevent calcium uptake into the tomato plant. Excess sand allows minerals to filter out. Excess clay retains water and causes root rot. Both contribute to low calcium uptake and to BER.

How do I perform a particle test?

Particle soil testing can be done at home or professionally. One common test is the particle soil ratio test, the 'Mayonnaise jar' method. To obtain soil samples, dig to 8" to 12" deep.

Place three inches of dry, crushed garden soil in a tall clear jar.

Fill jar with water.

Shake jar well and let contents settle for three days.

Sand and silt will settle in five hours, but clay will remain suspended for up to three days. After three days, study the content without disturbing the layers. Sand will have settled to the bottom, silt will be in the middle and clay will surface to the top. (Above these layers will be the water.) Measure the height of each layer. Remember the ratio should be two-parts sand, two-parts silt and one-part clay.
The second method of physical soil testing is the professional method. It is important to learn soil sample collection information from the testing site, and to follow their recommended soil sample gathering methods.  If you have several gardens, it is important to test each area.
How do I treat soil to get particle balance?

When clay, sand and silt are not in balance it is important to consult your state agriculture extension center as to the type and amount of additives needed to prevent BER. Appropriate amounts differ per area of the country.

Generally:
With high clay soil - add humus or gypsum.
With high sand soil - add humus or peat moss.
With high silt soil - add humus.

UNIT 4: Soil pH

Content
What is balanced pH soil?
The pH is an abbreviation for the 'power of Hydrogen'. It represents the concentration of hydrogen-ions. In gardening terms - when the pH reading is optimum, the nutrient reactions will be most effective.

The pH readings show degree of acid or alkaline in a substance. These readings range from 0 to 14, with 7 being neutral. Any number below 7 is acidic, and the any number greater than 7 is alkali. If a pH reading is 5, it is in the acidic range.

The ideal pH level for tomato soil preparation is 6.5.
If a pH soil reading of 6.0 or less is obtained, it is important to add materials to bring the pH up to at least 6.0, but preferably to 6.5.
If a pH soil reading of greater than 7.5 is obtained, it is important to add materials to bring the pH down from the alkali range, toward 6.5.
It is much more difficult to bring a pH level down from alkali ranges then it is to bring a pH level up from an acidic range.

0                                 7                                  14
Acidic                    Neutral                    Alkali

How does unbalanced soil pH affect tomatoes?
A chemical (pH) soil imbalance, either too acidic or too alkali, will prevent calcium uptake from the soil into the tomato plant.

How do I perform a pH test?
The chemically soil testing method can be completed at home with a pH soil test kit purchased at most local garden centers. The pH reading will be a color reading that is compared to a color chart showing pH levels. Also pH sampling may be tested professionally.

One advantage of home testing is that after performing a soil treatment, one may perform a second test to assess the results of the treatment. A re-test is a verification of successful chemical soil balance.

How do I treat soil to get pH balance?

Additives to improve soil pH:

0                                 7                               14
Acidic                   Neutral                    Alkali
(Add lime)                                    (Add sulfur)

To raise pH levels (if pH is lower than 6.0), add lime at a rate of 1 lb/30 square feet*. If a grower has only one tomato plant lime may be added at 2 cups per plant.
To lower pH levels (if pH is greater than 7.5), add aluminum sulfate (15% sulfur) at a rate of 1 lb/100 square feet**.
It takes 1 lb/100 square feet to lower pH 0.2. Therefore, to lower pH one whole point, it takes 5 lbs/100 square feet.

*30 square feet may be 5 feet x 6 feet ... or 3 feet x 10 feet, etc.
**100 square feet may be 10 feet x 10 feet ... or 5 feet x 20 feet, etc.
UNIT 5: Balanced Soil Validation

Content
After soil treatment it is important to re-test the soil to verify soil balance. By not retesting, one can only assume that the soil is balanced.

To be scientifically accurate the re-testing must continue until soil balance is reached. A conversational analysis of the scientific soil testing process might look like this:

Plant. (No.)
Test, then plant. (Yes, if the 1st test verifies soil balance.)
Test, add additives, then plant. (No, soil balance has not been verified.)
Test, add additives, test, then plant. (Yes, if the 2nd test verifies soil balance.)
Test, add additives, test, add additives, plant. (No, soil balance has not been verified.)
Test, add additives, test, add additives, test, plant. (Yes, if the 3rd test verifies soil balance.)

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