Unless you use ready prepared
cloves for planting, the first job to be
done is to split the garlic bulbs into cloves.
The job is made easier if the bulbs are
dried further so that the outer skin splits
allowing access to the cloves. Only the
best bulbs are used for planting and should
be handled carefully to prevent damage.
Dipping the cloves in fungicide immediately
after splitting can help prevent rotting.
Some suppliers offer this as a service.
If Stem Nematode is a problem, the cloves
can be hot-water treated at 46ºC for
2 hours in a 0.5% formaldehyde solution,
prior to the fungicide dip.
ADAS trials have shown
that it is best to use cloves greater than
1g in weight. Large cloves result in large
bulbs at harvest. Cloves weighing more than
4g have consistently given a higher number
of bulbs over 50mm in diameter than those
of 1g - 3g.
Yields per hectare have
been shown to increase with closer spacing
but at the expense of bulb size. In trials,
the optimum practical spacing using cloves
of 5g - 6.9g has been 30cm between the rows
(5 rows to a 1.83m bed), and 75mm within
the rows (44 plants per sq. m). Smaller
cloves (1g - 2.9g) should be planted at
100mm in the rows (30 plants per sq. m)
to provide a better chance of making adequate
bulb size. In practice it has been proved
worthwhile grading cloves for planting and
treating the grades separately.
If cloves are planted upside
down, yield is reduced and deformities increase.
The clove tip should be 50mm beneath the
soil surface. Planting methods are:-
Prefer Planter. This can be adapted for
use but will not plant closely enough and
can plant cloves upside down.
The Accord Planter.
This opens a furrow into which the cloves
are placed and then closes the furrow with
a pair of press wheels.
Or simply open a 75mm furrow
with a plough, place the cloves by hand
and manually cover with soil.
Nutrition will depend on
the natural fertility of the soil type being
used. Application of base fertilizer suitable
for autumn sown onions provides adequate
supplies of phosphate, potash and magnesium.
At Soil Index 2, for example, for phosphate
and potash, 150kg per ha phosphate and 125kg
per ha potash would be applied.
Trials on nitrogen response
were carried out at Efford EHS. Four rates
of top dressings from 75 - 300 kg per ha
were applied at various times from January
until May and these were compared. There
were no response differences between the
rates and it is suggested that 75 - 150
kg per ha nitrogen applied February / early
March will be suitable. Too much nitrogen
may adversely affect bulb development and
There is no trials information
on the water requirements of garlic, but
yield will be reduced if there is insufficient
water available in the main growing period
of late March to mid June. Irrigation during
dry periods at this time will be beneficial.
Spring planting on very light soils should
be avoided as there will be insufficient
time for full rooting and establishment.
Although experience has
shown that herbicides for bulb onions are
effective and safe for garlic, very few
of these materials actually have label approval
for use on garlic. Perennial weeds should
be eradicated before planting and a residual
herbicide applied soon after planting to
keep the ground free of weeds over winter.
A further residual is applied in spring
and contact / residual materials used for
later weed control. Currently, Simazine,
Linuron, Fluazifop-P-Butyl and Ethofumasate
have off-label approval for use on garlic.