Nut culture in British Columbia - Ministry of Agriculture and Lands

Later the leaves are very small and
lacking a healthy shiny appearance and
yields are reduced. Boron deficiency is
accentuated by dry soils. Dieback of the
terminal branches will occur with a
severe deficiency.
Magnesium – deficiency symptoms are
first observed late in the growing season
as light brown areas between the veins
and near the centres of the leaves. All
areas are subject to this deficiency
which can be controlled with foliar
sprays of epsom salts (magnesium
sulphate).
Zinc – deficiencies are most common on
alkaline soils in the interior valleys and
appear as crinkled, yellow-mottled
leaves. If the deficiency is more severe
the trees produce rosettes of small,
narrow leaves near the terminals.
Dieback can occur.
Manganese – usually only lacking in the
interior on soils laid down on old river
beds. A deficiency appears as mottled
yellow foliage.
Iron – like zinc, it is usually only deficient
in the interior on alkaline soils. If
deficient, the terminal leaves turn pale
green and yellow.
Rates of Application
and Procedures
A rough guide to nitrogen fertilizer use
for walnuts and chestnuts in the interior is
30 grams of 34-0-0 or ammonium nitrate
per centimeter of tree trunk diameter up to
15 cm and thereafter 80 g per cm to a
maxi-mum of 7 to 8 kilograms annually.
Filberts should receive proportionally less
as they are smaller trees – up to about 1.8
kg per mature tree. In coastal areas the use
of a complete fertilizer such as 4-10-10 or
6-8-6 is recommended.
The fertilizers should be applied in a ring
around the drip line of the tree. It may be
applied in late winter or early spring but
should never be applied during the summer
or autumn as it will delay hardening-off
and increase the risk of winter injury
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Pruning
Except for the initial pruning to shape
the trees, they should receive only minimum
pruning to remove low or damaged
limbs. Walnuts are very prone to sap
bleeding if pruned in the early spring just
prior to leafing out. Bleeding can be minimized
by pruning when the trees are fully
dormant. However, no bleeding will occur
if pruning is carried out after the trees have
reached full leaf.
Filberts need light pruning to encourage
them to branch out evenly in the early
years as they have a tendency to be ‘vaseshaped’
and lopsided. After the original
trunk or stem has begun to produce a good
crop the trees can gradually be allowed to
produce additional stems as mentioned
previously. Once the original stem begins
to produce small clusters of nuts, it should
be sawn off at the ground level and a
sucker allowed to take its place. With this
renewal type pruning the above ground
portion of the tree remains young, vigorous
and productive.
Harvesting and Drying
All kinds of nuts should be harvested
promptly when mature to avoid
discolouration of the shells and meats.
Harvesting may sometimes be done in a
single operation after the nuts have fallen
or have been shaken from the tree.
Frequently the nuts must be gathered
several times as they fall. Frequently
gathering is the best way to prevent losses
to squirrels and birds. After nuts have been
gathered they must be suitably dried or
“cured”.
With Carpathian walnuts, filberts and
pecans the husks or hulls usually crack and
the nuts will fall free. If desired, the nuts
may then be washed to remove bits of the
husk and any mud. Most empty shelled
nuts will float and can be removed. To
remove any stains and reduce mold growth,
household bleach may be added to the final
rinse (15 ml or 1 tbsp/2 litres), but nuts
with shells that have cracked open should
not be given this treatment. After cleaning