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Blossom end rot
is perhaps the most common physiological disorder you will experience
with growing tomatoes. Typically it shows itself as a circular, dark
brown patch of skin found at the flowering end of the fruit – hence the
name. As the fruit grows this unsightly dark patch gradually toughens
and shrinks back into the fruit.
What Causes Blossom End Rot?
disorder is caused by a deficiency of calcium within the plant and its
relatively poor mobility through the plant tissues. This is important as
calcium is not only a valuable component within the plant cell walls
and is also vital in the production of new cell walls and the normal
function of plant membranes. Because of this, the problem of calcium
deficiency is most noticeable in areas where there is significant cell
division, and when you consider the rapid growth generated in the
production of a tomato fruit it is understandable why cell death
(necrosis) can occur in this region when the availability of calcium is
Calcium deficiency should not be confused
with lack of availability as its uptake can be inhibited by high levels
of potassium, magnesium and /or ammonium-nitrogen within the root
environment. Surprisingly other factors that can inhibit the uptake of
calcium can include water stress and high humidity. To a lesser extent
boron deficiency can also be a factor as it is needed for the transport
of calcium within the plants tissues.
How to Treat Blossom End Rot
is no magic bullet to deal with blossom end rot and this is because of
the complex inter-relationships that calcium has with other elements
within the plants cells. However a holistic approach is normally best
although signs of improvement are usually slow to appear.
probably worth doing a pH test first as acidic soils have naturally
lower levels of calcium compared to alkaline soils. If this is the case
then apply lime to the soil, but go by the manufacturer’s
recommendations according to soil type - try to end up with a soil pH of
about 6.5. You can also consider spraying the affected fruit with
solutions of calcium nitrate or calcium chloride. This is applied at a
concentration of 2 grams per litre on a fortnightly basis.
the greenhouse environment it's important to keep humidity levels low,
so make sure there is good ventilation throughout the growing space. Air
circulation can be further improved by removing the older, lower leaves
from the base of the plants.
Never apply fertilizer to
dry soil and any irrigation that is in place must be sufficient to
maintain a good, steady, growth rate for the plants – this is
particularly important during the summer period. For outdoor tomatoes,
giving the soil a good mulch can be very helpful in maintaining water
levels in the soil especially in times of moisture stress. When feeding
your plants use either a specific tomato fertilizer or use fertilizers
that are low in nitrogen, but high in superphosphate.
all of these solutions will help in some way to reduce the incidence of
Blossom End Rot in tomato plants it is always best to try and avoid the
conditions that promote it in the first place. By using good plant
husbandry as outlined above you will hopefully never have a incidence to
worry about controlling.