split on citrus tree
have a citrus tree named Tangor Dweet which I planted about four
years ago. The tree has grown normally and looks reasonably healthy.
The fruit however never gets to mature before they split. Initially
I didn't put anything on the tree. I have tried lime and fertiliser
at different times. Watered at different rates, etc. Yet always
the fruit splits.
splitting is believed to stem from stress as a result of extreme
fluctuations in temperature, humidity, moisture availability and
possibly fertiliser levels. For example in hot, dry weather the
tree will become drought stressed and will draw water from the developing
fruit, causing the skin of the fruit to soften. If the tree is then
given a heavy watering, the dehydrated fruit will swell, causing
the skin to split.
Young citrus trees that
are not fully established, dwarf varieties with shallow roots, and
trees that are grown in sandy or porous soils do not retain water
very well, and the same can happen to these. Regular watering is
therefore essential until the tree has become fully established.
High humidity after a
dry period can also be a trigger for fruit split, and rinds that
have been sunburned or otherwise damaged can lose their elasticity
and therefore be susceptible to splitting.
Remove any damaged fruit
and monitor your tree's irrigation levels to avoid major fluctuations
in soil moisture. Water deeply once a week in the growing season
and mulch to keep the roots cool and moist in the drier months.
Citrus trees enjoy a
slightly acid soil, so adding lime will only make your soil more
alkaline. Zinc and iron are locked up by the soil in alkaline conditions,
so your tree may start to develop symptoms of a trace deficiency
yellowing of leaves.
Citrus trees also need
regular feeding, including large amounts of nitrogen and potassium
for good fruit development. A mature tree should be given 450-500
g of citrus food every year (you can buy specially blended citrus
food such as Yates Gro-Plus Citrus Food). Two-thirds of this amount
should be given in July or August and the remainder in January or
February. The ground beneath your tree should be watered well before
and after applying the fertiliser. The fertiliser should be scattered
around the drip line of your tree. This is the area underneath the
outer foliage where, literally, the drips fall down when it's raining.
The key here is watering
and feeding. Once you have this to a regular pattern, you should
see an improvement in your fruit.
by Dr Dan Blanchon from Unitec's Diploma in Sustainable Horticulture and Bachelor
of Resource Management.
with permission from NZOOM Home and Garden content,
from the previous
The views expressed here are not necessarily those of the RNZIH