Horticulture Hotline 05/20/19
By Bill Lamson-Scribner
Blossom end rot is a very common problem for tomatoes (it
can also get on peppers, squash and watermelons). A dark water soaked spot appears on the
blossom end which is opposite the stem end of the tomato. This spot usually gets bigger and turns
black, and then mold will grow on the surface.
Ways to avoid blossom end rot include soil testing to be
sure your calcium levels are adequate.
If calcium is lacking, you can amend it by adding calcium nitrate, lime,
gypsum or spray foliage with calcium chloride, calcium nitrate or Neptune
Harvest’s Crab Shell product (23% Ca and helps with nematodes).
Other factors that contribute to blossom end rot are:
·
Fluctuations in soil moisture. Letting the soil get very dry then very
wet. Cotton Burr Compost used as a soil
amendment or as a mulch will add organic matter to the soil reducing these
fluctuations.
·
High nitrogen fertilization. If plants get too much fertilizer, then get
hit by a dry spell, this will cause blossom end rot. Avoid trying to grow the monster tomato bush
by piling manure or fertilizer around the plant.
·
Root damage.
Root damage can be caused by cultivating (hoeing) too close to the
plant, having the tomatoes sit in water after a rain, nematodes and excessive
salt. When hoeing, stay away from the
root zone of the tomato plant. Be sure
you have well drained soil (Cotton Burr Compost will help), so your roots will not
suffocate. Test your soil for sodium and
remove the salts by leaching the salts out or by applying a salt removing
product. If you have nematodes, plant in
a different area or in a container. Using Neptune Harvest’s Crab Shell product
has shown to reduce nematode populations by building up chitin eating bacteria
in the soil.
·
Container growing. Many potting soils are
sterile and ‘soilless’ – meaning they do not have any fertilizer or nutrients
built into the soil. Happy Frog or Ocean Forest soils would be an exception to
that. If you are growing in containers, be sure you are adding what the plant
needs for proper growth.
The main thing in controlling blossom end rot is to soil
test and be sure there is plenty of calcium in the soil before you plant the
garden.
Always read, understand and follow product label. The
product label is a Federal Law.
