Using Bulbils to Establish Garlic
Garlic crops are typically started by planting cloves. As a head of garlic only contains from 5-10 usable
cloves the cost of holding back 10-20% of the crop to use as seed for the next season can be substantial.
Costs are even higher if the grower opts to buy seed. Another concern with using cloves to establish the
garlic crop is the potential for the cloves or the soil adhering to the cloves to introduce diseases such as
Fusarium basal rot or garlic cyst nematodes. Hardneck (rocambole) type garlic produces scapes or flower
stalks that yield 10-200 small bulbs (bulbils) which can be used as planting material. Using bulbils to
establish a garlic crop has several potential advantages;
Rounds produced when bulbils are planted
Scape forming on hardneck garlic
Bulbils formed by hardneck garlic
a)
a)
eliminates the need to hold back 10-20% of the harvested bulbs to use as seed
It
b) As bulbils grow on stalks, they should be less likely to harbor soil-borne diseases/pests
c) Bulbils are easier to harvest, store and prepare for use as seed than garlic bulbs
d) Planting of garlic cloves is done by hand or with specialized equipment, whereas bulbils can
be planted using slightly modified corn seeding equipment.
However, there are some potential limitations of using bulbils to establish the garlic crop;
a) Growth of the scape and associated bulbils has the potential to compete with the bulb for
resources, leading to a reduction in bulb size at harvest
b) Bulbils tend to be much smaller than a standard clove. As the early season vigor of a garlic plant
is directly correlated with the size of the clove or bulbil planted – the small size of the bulbils puts
the young garlic plants at a competitive disadvantage against weeds etc.
c) The small size of the bulbils means that it typically takes two growing seasons to produce a full
sized bulb. In the first season, a crop established from bulbils typically yields a round, pea to
marble-sized single bulb which is similar in appearance to a pickling onion. If these “rounds” are
replanted they will form a standard sized bulb with the normal number of cloves in the 2 nd year.
The objective of this study was to address a number of the questions that arise when growers
consider using bulbils to establish a garlic crop;
a) What is the impact on yield and bulb size of not removing the scapes, but instead letting the
bulbils form and mature?
b) How many usable bulbils are formed per scape? Does that number vary amongst cultivars? Is
that number at all related to the number of cloves found in each bulb?
c) How well does a crop grown from “rounds” over winter and how big a bulb can be expected
when “rounds” are planted?
d) Is there any way to produce large, fully cloved bulbs from bulbils in a single production season?
2013 – Growing Garlic from Bulbils
In early fall of 2012, mature scapes were harvested from the
popular hardneck garlic cv. Music. In early October the bulbils
were planted using a standard single row push planter set up with
the seeding disks recommended for planting large types of corn.
Check rows of cv. Music were established using the standard
approach of hand-planting individual cloves. At freeze-up the test
plot was covered with 15 cm of straw spread over a sheet of woven
field cover. Use of the mulch + field cover coupled with the
exceptional amounts of snow received over the winter of
2012/2013 provided excellent over-winter protection for the trial.
The straw+cover was removed as soon as the snow melted (early
Mulching to protect fall-planted garlic
May) in 2013. The crop established from bulbils emerged about 10 days later than the crop established
using cloves. About 70% of the bulbils planted survived the winter – while 67% of the fall planted cloves
survived to produce plants. The crop from bulbils grew more slowly than the crop established from
cloves. This slow growth made weed control very important. The plants established from bulbils were
ready for harvest by mid-July. By contrast, the plants established from cloves continued to grow until
mid-August.
On average, the bulbs produced by the crop grown from bulbils weighed 3.7g. As the average weight of
the bulbils planted was 0.22 g, this means the yield multiplier for the bulbil crop was 16 fold ie; for every
1g of bulbils planted 16g of bulbs were produced. By comparison, the yield multiplier for the crop
established from cloves was only 6 fold (60g avg. bulb wt harvested when a 10g avg. clove wt was
planted = 6 fold multiplier).
2014 - Using Cloves vs Rounds vs Bulbils to Produce cv. Music Garlic
This trial allowed for comparison of the three different ways available to establish a garlic crop – the
standard approach of planting cloves, versus using bulbils, versus using the uncloved rounds that arose
when bulbils were planted the previous year. As bulb size in garlic is somewhat related to the size of
clove/bulbil planted, it is noteworthy that the bulbils were smaller than the rounds, with the cloves
representing by far the largest (and therefore the most expensive) “seed” planted.
Avg. Weight
Planted (g)
8.2
3.7
0.7
Cloves
Rounds
Bulbils
Avg. Weight of
Bulb Harvested (g)
53.3
22.3
7.8
Yield Increase
% cloved bulbs
7:1
7:1
10:1
100
94
3
From a crop management perspective …
a) The bulbils and rounds required no pre-plant preparation and could be planted mechanically.
A planting disk with larger orifices was required for the rounds versus the bulbils. By
contrast the cloves had to be cracked out of the bulbs and planted by hand.
b) The plants that arose from the bulbils were slower to emerge and develop than when rounds
or cloves were used to establish the crop. These small plants could be out-competed by
weeds and required more careful weeding than when rounds or cloves were used to establish
the crop.
From a yield perspective ….
a)
The larger the material used to establish the crop (cloves vs rounds vs bulbils), the larger the
resulting bulbs harvested from the crop.
b) The yield multiplier (g of garlic harvested per g planted) was slightly higher (10:1) for the
bulbils than for the rounds (7:1) or cloves (7:1).
Using rounds or cloves to establish the crop produced bulbs that had sub-divided into cloves. However,
when bulbils were used to establish the crop very few bulbs matured to the point where they were ready
to sub-divide into individual cloves – instead over 95% of the bulbs harvested were rounds.
2014 - Comparison of Yield Performance of 6 Garlic Cultivars Grown from Cloves vs Bulbils
In the fall of 2013 bulbils or cloves were used to establish plantings of 6 different cultivars of hardneck
garlic. The trial was established in mid-October of 2013 using the methods outlined above. The plot was
covered with straw mulch two weeks later. Snow pack over the winter of 2013/2014 was moderate and
there were extended periods of extreme cold. The straw/crop cover combination likely enhanced the
over-winter survival of the 2013/2014 garlic crop. The straw+cover was removed in early spring as the
crop emerged. Emergence of the 2014 garlic crop coincided with several flooding events. This flooding
killed some plants and had a long lasting negative impact on the vigor of the survivors.
From Cloves
From Bulbils
Planted
(g)
Harvested
(g)
Planted
(g)
Harvested
(g)
Yield
Increase
23
Yield
Increas
e
8:1
Spanish Red
3
0.5
36.3
72:1
German Red
8
48
6:1
0.6
22.2
37:1
Music
8
53
7:1
0.7
7.8
10:1
Persian Star
4
35
8:1
0.1
2.3
20.1
Russian Red
5
34
7:1
0.3
1.4
5:1
Yugoslavian
10
40
4:1
0.1
0.8
8:1
6
38
7:1
0.4
11.8
25:1
Avg.
Averaged across the 6 cultivars tested, the bulbs harvested when
cloves were used to establish the crop were 3 times larger than
when bulbils were planted. However, for cv. Spanish Red the
bulbs grown from bulbils were actually larger than those
produced when the crop was grown from cloves.
Averaged across the 6 cultivars tested, the yield multiplier for
the bulbils was more than 3 times higher than what could be
expected when cloves are used to establish the crop. The highest
yield multiplier (72:1) was seen with cv. Spanish Red – which as
noted above had produced large bulbs even when relatively
small bulbils were planted.
% forming
Cloved Bulbs
Avg Weight of Cloved Bulbs
From Bulbils
From Cloves
(g)
(g)
43
23
Cloves/bulb
From Bulbils
From Cloves
(g)
(g)
8
9
Spanish Red
75
German Red
72
28
48
4
7
Music
15
12
53
6
8
Persian Star
0
0
35
Russian Red
0
0
34
Yugoslavian
0
0
40
When bulbils are used to establish a garlic crop after the first year in the field the resulting bulbs will
typically consist of only a single large clove (a round). While this was the case for many of the cultivars
evaluated in the 2014 trial – the Spanish Red and German Red cultivars actually produced a high
proportion of bulbs (>70%) that were fully cloved. The potential to produce a standard sized fully
cloved bulb in a single growing season using bulbils as the planting material could represent a
significant step towards improving the cost and operational efficiency of garlic production.
However, it should be emphasized that only a few cultivars appeared to have this potential. The
cultivars with the highest average bulbil weight planted tended to produce the largest heads with the
highest proportion of fully cloved bulbs. The linkage between the size of the garlic propagule planted
versus the size of the head that plant will produce has been previously established. This suggests that the
likelihood of being able to grow large fully cloved bulbs within a single growing season when bulbils are
planted could be increased by;
a) Growing cultivars that produce large bulbils
b) Selecting for the largest bulbils within the material harvested for any given cultivar.
c) Developing production practices that would increase the average size of the bulbils
produced by the plant
2013 and 2014 - Bulbil Production
In the fall of 2012 and 2013 a number of different cultivars of hardneck garlic were planted using cloves.
The plots were maintained through the subsequent summer as outlined above except that when scapes
began to form in early summer, they were removed as recommended on 75% of the plants, but were
allowed to mature on the remaining 25% of the plants in each row. Once the crop matured, the bulbs and
scapes were weighed and the number of bulbils per scape was counted.
The size of both the bulbs and bulbils in the 2014 crop was substantially lower than in 2013. This could
be attributed to the lasting negative impact of the flooding event that occurred early in the 2014 growing
season.
2013 trial
Cultivar
German Red
Korean Purple
Music
Persian Star
Russian Red -1
Russian Red -2
Salt Spring
Spanish Red
Yugoslavian
Average
Bulb Weight (g)
Bulbils
Scape
Removed
Scape
Intact
# per head
Avg Wt
(g)
71
54
59
48
54
47
42
58
67
56
90
50
56
45
42
19
45
44
50
49
11
7
64
220
67
50
3
8
85
57
1.57
1.43
0.22
0.05
0.12
0.20
2.00
1.00
0.07
0.74
Total Weight
(g)
Bulb+bulbils
Cloves
per bulb
101
60
70
56
50
29
51
52
56
58
11
6
5
6
8
6
10
6
8
7
Total Weight
(g)
Bulb+bulbils
Cloves
per bulb
2014 trial.
Cultivar
Bulb Weight (g)
Scape
Removed
Scape
Intact
Bulbils
# per head
Avg Wt
(g)
German Red
Korean Purple
Music
Persian Star
Russian Red
Spanish Red
Yugoslavian
Average
50
30
53
37
33
27
43
39
46
49
22
38
21
25
34
5
28
26
96
53
26
101
48
0.63
0.92
0.52
0.03
0.06
0.52
0.06
0.39
54
62
23
46
31
27
41
6.4
6.1
5.6
8.4
7.2
7.9
3.9
6.5
This study indicated that;
a) In both years, leaving the scapes intact reduced the size of the bulbs by an average of 12%.
The impact of leaving the scapes intact on bulb size was greater in some cultivars than in
others. If the bulbils were used as planting material, the associated reduction in bulb size was
more than offset by an increase in total usable material per plant contributed by the bulbils –
see the bulb+bulbils data.
b) The cultivars tested showed a huge range in the number and size of bulbils produced per
flower head. In most, but not all cases, if the cultivar produced a large number of bulbils per
flowering head, the average size of the bulbils was small.
c) There was no correlation between the number of bulbils per plant produced by a given
cultivar and the number of cloves/bulb produced by that cultivar
d) As plant vigor of garlic is closely related to the size of the bulbils or clove used to establish
the crop, there are some obvious concerns regarding the growth potential of the cultivars that
produce extremely small bulbils.
Culinary Quality Considerations
The uncloved rounds produced when bulbils were planted could be easily substituted for standard cloves
of garlic in all standard food uses. The rounds were about the same size as the cloves, did not have to be
cracked out of the head and were easier to peel than standard cloves. The rounds also stored well – they
appeared to lose moisture more slowly than standard cloves and were less prone to sprouting while in
storage.
Suggestions for future work
This study confirmed the potential to use garlic bulbils as planting material in certain hardneck types of
garlic. Future work should focus on improving the efficiency and efficacy of this process by;
a) Using only the largest bulbils as planting material – this should increase the size and degree of
cloving of the resulting garlic heads
b) Investigating the potential to not harvest and replant the crop derived from small bulbils – but
instead to leave it in place for the full 2 years required to produce a full size fully cloved head.
This process will come with additional challenges for weed control and fertility management.
c) Assessing potential consumer acceptance of garlic rounds as an alternative to the standard cloved
bulbs.
This project was supported by;
the ADOPT Program of Saskatchewan Agriculture and Food.
Special thanks to the Saskatchewan Vegetable Growers Association
for collaboration on this project