Garlic Agronomy Research
The following is a collection of articles detailing garlic agronomy research carried out by the Vegetable Program. The articles are available as HTML documents and PDF files.
Factors Influencing Performance
of Fall Planted Garlic PDF
Evaluation of Variety Performance
for Fall-Planted Garlic in Saskatchewan PDF
What to do with that
straw mulch in your garlic patch? PDF
Fall planting garlic has the potential to increase yields providing the crop survives the winter. Studies conducted by the University of Saskatchewan in 1992 and 1993 identified little need to mulch fall-planted garlic. The trial results suggested that mulching the crop actually reduced yields and exacerbated problems with weed control. However, commercial growers reported limited or variable success with fall planting the crop, primarily due to problems with winter kill. These differing responses to fall planting may reflect; 1) differences in the site ie; snow cover or b) differences in the winter-hardiness of the planting material.
This trial evaluated the influence of fall mulching on the overwinter survival and subsequent yield performance of a number of garlic genotypes. The trial was conducted at the Department of Plant Sciences Horticulture Fields Research Station in Saskatoon. The site features a clay soil and is well sheltered. The planting material was collected from local growers, seed companies and local retailers. The trial was planted in early October.
Field conditions were excellent at planting with abundant soil moisture. Each genotype was planted in twin 4 m long rows with 50 cm between rows and 8 cm between cloves in the row. Half of each plot was mulched with 15 cm of barley straw just after freeze up (late October). There was limited rainfall following planting and the winter was unusually warm and dry. Limited snowfall coupled with several mid-winter thaws resulted in minimal snow cover for the duration of the winter. Standard management practices were employed during the following growing season. The straw mulch was removed once the crop began to emerge in late-April. The crop was harvested once the tops began to senesce. (image) Plant stands, yields and bulb characteristics were evaluated following the harvest.
Mulching delayed emergence of the crop in the spring - however, plant
stands and bulb yields were all improved by mulching. The degree of response
to mulching treatment varied greatly between genotypes. Some genotypes
completely winter-killed without mulch but did well with the mulch. In
a few cases, mulching actually reduced overwinter survival and yields.
Although mulching fall-planted garlic represents a considerable additional cost, this practice may represent a good insurance measure, particularly at exposed sites or when relatively cold sensitive garlic types are being grown.
Commercial production of garlic is limited on the Canadian Prairies, as growers find it difficult to compete in the wholesale markets with low price imported product. There is however considerable interest in growing garlic in the hobby garden and for local sale.
Variety selection is one of the most important decisions any garlic grower makes - but it is particularly important on the Prairies as growing conditions are challenging. Trials conducted a decade ago by the University of Saskatchewan demonstrated that fall planting generally results in superior yields and quality under Prairie conditions ... but only if adapted varieties were planted. In 2002 and 2003, we re-examined the performance of a range of garlic varieties in fall planted trials in Saskatchewan.
The trials were conducted on research plots managed by the Department of Plant Sciences at the University of Saskatchewan in Saskatoon SK. Planting material was obtained from commercial and private suppliers of “seed garlic”. A couple of varieties were also obtained “off the shelf” from local retail groceries.
The plots were planted out in mid-October. This planting time allowed some root development but no emergence prior to freeze up. The plots were mulched with approximately 10 cm of wheat straw after freeze up in mid-November. For the last few years, mulching has been critical to successful overwintering of garlic on the Canadian prairies, as snow pack has been limited. The mulch was removed as the crop emerged in mid-April.
Standard management practices were employed throughout the growing season. Weeds were controlled by tillage. The crop was irrigated as needed. The scapes were removed from the stiffneck types. No significant problems with insect pests or diseases were observed - although some varieties sold as “seed garlic” appeared to be infected with leaf streak virus. These lines had poor vigor and died early. Each variety was harvested once 50% of the tops were down. The bulbs were field dried and then rubbed clean prior to evaluation of yields and bulb characteristics.
Most varieties showed good overwinter survival, despite the lack of snow coverage. Although softneck garlic is considered to be less winter hardy than stiffneck types, the mulch treatment provided adequate protection for both garlic types in this trial. Yields were generally above commercial norms for garlic - this is typical of small plot trials.
Of the softneck types, “Fishlake F4" and “Fishlake F40" along with “M&M Softcore” were outstanding. “M&M Stiffneck” was the best stiffneck type and was overall the best variety tested. “M&M Stiffneck” winters well and gets off to a very early start, producing high yields of very large attractive bulbs with relatively few cloves/bulb. The variety “Music”, which is popular in other areas of Canada, performed reasonably well under Prairie conditions. It is interesting to note that at least one of the varieties purchased at a very low price directly off the grocery shelf appeared as healthy and performed as well as many of the more expensive types of “seed garlic”. Buyer Beware continues to be good advice when purchasing garlic for planting.
This research was supported by the Agriculture Development Fund of
Fall planting garlic has the potential to increase yields, providing the crop survives the winter. Previous studies conducted by the University of Saskatchewan suggest that mulching fall-planted garlic with straw will improve overwinter survival and subsequent yields - especially in years or situations where the winter snow cover is limited. The straw mulch is typically removed early in the spring ... otherwise the soil is too slow to warm and crop development is delayed. The question then arises ...what to do with all that used straw ? One answer may be ... put it back on again a bit later!
Garlic is a cool season, moisture-loving crop. Using the left over straw as a mulch between the rows should keep the soil cool and moist, while also suppressing weeds. In mid-June we took the straw that had previously been used as an overwinter mulch and spread it over one half of our garlic research trial. At that time, the garlic plants were already 30 cm tall. We attempted to direct the straw between the rows. Although some plants were lightly covered, wind action soon uncovered these plants. Any weed escapes in the straw mulched plot were controlled by hand weeding. The non-mulched plots were also hand weeded. The crop was harvested at maturity and yields and bulb quality assessed.
The 2005 growing season was relatively cool, with above normal rainfall. This resulted in excellent vigor and growth in the garlic trial. The mulching treatment appeared to delay maturity of the garlic crop. In the stiffneck types of garlic, this delay resulted in a 17% increase in total bulb yields. No corresponding yield benefit was observed when softneck types of garlic were mulched. Bulb color was often improved by the mulching treatment - but mulching also seemed to increase problems with bulb decay. Bulbs from the mulched areas seemed prone to falling apart, releasing the individual cloves.
In conclusion, using leftover straw appears to have both advantages and drawbacks. Greater benefits might be anticipated in a warmer year. Removal of the straw as the crop begins to mature may also be advisable.