Prepared by A. Swatton,
Horticultural Consultant, ADAS Cardiff,
St. Agnes Road, Gabalfa, Cardiff CF4 4YH
Following the meeting between
myself and Bryan Edwards at the DBRW, Newtown
Office, on 22 April and a subsequent letter
of affirmation dated 17 May 1993, the report
that follows describes the factors that
will be taken into consideration for possible
garlic production in south east Wales.
CLIMATIC AND SITE CONSIDERATIONS
Garlic is often considered
to be a Mediterranean crop but is in fact
successfully grown, albeit on a small scale,
in the UK. The largest UK producer is situated
on the Isle of Wight, growing approximately
50 acres of garlic. ADAS has carried out
trials on garlic, both at Efford Experimental
Horticulture Station in Hampshire and Stockbridge
House Experimental Horticulture Station
in Yorkshire. Even on this northerly site,
satisfactory yields of garlic were achieved
even in 1990/91 which had a very cool spring
and early summer. Nearer to home, garlic
has been successfully grown in the Welsh
border region near Presteigne.
Garlic has certain climatic
requirements for success:
A “cold requirement”.
It is necessary to expose dormant cloves
or young plants to temperatures of 0
- 10ºC for 1 - 2 months. This normally
occurs in storage sheds, or after the
crop has been planted in the case of
an autumn planting, in the field from
September until December.
A “warm spring”.
Maximum vegetative growth occurs at
temperatures around 16ºC in short
days between late March and mid June.
Accordingly, warm temperatures at this
time of the year are important to optimise
leaf production, which is then responsible
for swelling the garlic bulbs.
A “dry harvest”.
Dry weather at harvest in late July
/ early August is essential to ensure
clean skins on the bulbs and to reduce
the incidence of rotting in subsequent
It is suggested that garlic is planted from mid October until
mid November, but this may be dictated by
soil conditions. ADAS has found that yield
is little affected by late varieties, as
late as February. Soil type should be freely
drained and easily worked, not only for
good planting conditions but also for winter
survival, rapid soil warming in spring and
easy harvesting. Water supplies in the growing
period must be adequate to facilitate maximum
Winter survival has not
been a problem in UK trials, garlic being
Local topography (site,
slope, shelter) can make quite a difference
to the performance of the crop because of
the temperature requirement of the crop.
Suitable soils predominate
in the area of the Wye and Usk valleys,
notably Oglethorpe Series, a deep well-drained
loam over gravel in the Usk valley, especially
in the Brecon-Crickhowell area. Also, Bromyard
Series, a well-drained fine silt, east of
the Black Mountains and in the Hay-on-Wye
area of the Wye Valley. Meteorological data
from the area is included in Appendix
1, in comparison with similar data from
the Isle of Wight and Stockbridge House
areas. On average, this area has a slightly
wetter spring but late summer rainfall and
spring / summer temperatures compare well
with the other sites.
Calendar of Production
cloves are bought in, the cycle begins with
splitting garlic bulbs into individual cloves
for planting in September. These will need
to be sorted by size and dipped in fungicide
for planting. Cloves are planted direct
into the field in October and November,
but late varieties could be delayed until
February. Trials work has shown that planting
cloves in peat blocks, over-wintering in
glass or plastic tunnels and planting out
in spring, is feasible but expensive.
Vegetative growth occurs from late March
until the beginning of June. At this stage,
in response to day length, the plant begins
to produce the bulb, which continues until
mid-July. The bulbing period can be shortened
by drought or extremely high temperatures.
The crop is then harvested from late July
until the middle of August, is “dressed”,
dried and stored for sale if necessary.