NEIGHBORHOOD GARDEN FOR APRIL 19, 2008
AVOIDING BLOSSOM END ROT IN TOMATOES
AND OTHER GROWING TIPS
END ROT” is a very common problem that can be prevented. The cause is lack of calcium going to the fruit because of
moisture stress and/or over fertilization. Calcium dissolves in water
and moves through the plant in the vascular system.
Under moisture stress from irregular watering, the calcium goes
to the leaves and thus is deficient in the fruit causing blossom end
rot. It can occur even in gardens where there is abundant calcium in the
soil. Most gardens in Southeast and South Central Nebraska have
sufficient calcium in the soil and additional applications, either to
the soil or on the leaves (foliar), does not help stop the problem.
Blossom end rot in tomatoes usually occurs on the first fruits of the
season and may be seen on other fruits and vegetables such as
watermelon, peppers, and eggplants. Rapid plant growth from over
fertilization with nitrogen, and moisture stress from irregular watering
are the two major causes why calcium does not go to the fruit.
In summary, the
first step in the prevention of blossom end rot and other plant diseases
is “DO NOT OVER FERTILIZE!!!”
Also, if you have too much nitrogen in relation to phosphorous, you may
have beautiful big tomato plants but very few tomatoes. Nitrogen makes
your foliage grow, and phosphorous is good for flowering and fruiting.
cause of Blossom End Rot is irregular watering, especially during
periods of fruit set, fruit development and rapid plant growth. Tomatoes
need 1 inch of water per week during hot windy weather. One-half inch of
water applied twice a week is better than one watering per week.
Maintaining uniformly adequate soil moisture throughout the season is
The third way
to prevent not only blossom end rot but tomato blight is through the use
of mulch. Mulch can be
straw, dry grass, leaf clippings that have been run through a mower,
compost, or 4 to 6 pages of newspaper. I spread out newspapers, 4 to 6
pages deep around and between my plants and then put straw, compost or
soil over the top to hold them down. This mulch helps to conserve
moisture and prevent the soil from drying out rapidly. Mulch also helps
prevent the disease pathogens that are in the soil from splashing up
onto the leaves.
diseases in your tomato plants do not water overhead with a sprinkler. I
put a soaker hose under the newspapers or mulch. If you have to overhead
water, do not water after 2:00 pm in the afternoon. Many disease
pathogens are in the soil. A drop of water on the leaf most of the
evening helps the pathogen inoculate the plant. Therefore, water early
so the plant leaf is dry going into the evening. You can’t prevent the
rain but you can decrease the amount of disease by good watering
practices. And, as mentioned above, mulch helps prevent disease
pathogens from splashing up onto the leaf.
The fourth tip
in growing tomatoes is to purchase disease resistant varieties. When you
go to the Garden Center and purchase tomato plants, do you pay attention
to all the information on the tag? Do you know what all those letters
and words mean? Some of the strange words and letters on the tag
VFNT: A plant tag may have
one letter, two letters, or all four letters. These letters are not
college degrees but do indicate disease organisms that hybrid tomatoes
have been bred to resist. The V stands for Verticilium Wilt; the F means
the plant is resistant to Fusarium Wilt; the N stands for nematode
resistance; and the T for Tobacco Mosaic resistance. Remember, they are
disease resistant not disease proof.
INDETERMINATE: Determinate tomato plants are usually shorter and do very
well in containers. The major characteristic of determinate varieties is
the fact that they usually have a big flush of fruit and then a few
fruit the rest of the season. If you like to can or freeze most of your
tomatoes all at once, then look for determinate varieties. Indeterminate
varieties of tomatoes start setting on fruit and they continue until
frost. These varieties are usually taller and need to be staked or
contained in a cage
plant tomatoes too early. Soil temperature, not air temperature is the
major consideration. If the soil temperature is too cold, the plants
will just sit, and if it is rainy, may start to rot.
your plants in good cages. I made my own cages from concrete reinforcing
fence. The fencing comes five feet tall and I cut pieces about six feet
long and bend them into a circle. These have lasted me for years. My
plants get very tall so I pound pieces of rebar about 5 feet long into
the ground to support the cages.
deep. Tomatoes can be
planted very deep and the hairs on the stem will develop roots. I strip
all but the top leaves off my transplants and then put the plant so they
are just above the soil line.
The last tip is to be sure and prune. When my tomatoes are about
3 feet to 4
feet tall, I trim
off the lower 8 inches to 10 inches of stems and leaves. This allows for
good air flow up through the plants and helps to prevent disease. In
addition you may need to go in during the month of July and do some
pruning. Don’t be afraid to prune and thin out your plant so you have
good air flow and large juicy tomatoes. Cutting off those stems is hard
for me to do, especially when they have blooms or even small tomatoes.
But I know it is good for the plant. As I mentioned many pathogens need
a drop of water on the leaf and if you do not have good circulation, the
leaf will not dry off. Also, make sure you do not plant your tomatoes
too close together. Powdery mildew, leaf blight, and other diseases love
damp wet conditions when there is poor air flow. Plants need good air
If you get a
good abundant crop, as I usually do, please share with the Food Bank, or
some other food distribution group. Or start a “Harvest Table for
Missions” at your house of worship. Go the second mile and put in one
or two extra plants just for sharing with an elderly neighbor, the Food
Bank, or your Mission Table.