Growing Great GarlicPam Dawling

Twin Oaks Community, Central Virginia

Author of Sustainable Market FarmingSustainableMarketFarming.com

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Garlic is a great crop! It’s not just bulbs!

Bulbs (and braids)

Garlic Scapes

Garlic Scallions (shown here)

Stages of Growth –Garlic is day-length sensitive

• No control over when garlic starts to make bulbs, only over how large and healthy the leaves are when bulbing starts, and how large the final bulbs can be.

• Bulbs start forming and no more leaf growth happens once day-length exceeds 13 hours, with air temperatures above 68°F (20°C) and soil temperatures over 60°F (15.5°C) as secondary triggers.

• 12 hours of daylight on the spring equinox. After that, the farther north you go, the longer the daylength is. Northern latitudes reach 13 hours of daylight before southern ones, but garlic does not start bulbing there at 13 hours because temperatures are not yet high enough. Temperatures cause harvest dates to be earlier in warmer zones than in cooler areas at the same latitude.

• It is important to establish garlic in good time so roots and leaf growth are as big as possible before the plants start making bulbs. Small plants on the trigger date will only make small bulbs!

Drying downHot weather above 91°F (33°C) ends bulb growth and drying down starts. It is

important to get plenty of good rapid growth before hot weather arrives.

Garlic can double in size in its last month of growth, and removing the scapes (the hard central stem) of hardneck garlic can increase the bulb size 25%.

Avoid confusion• Hardneck (with flower stalks or scapes, bigger

cloves, easier to peel, more cold-tolerant). • Softneck (no scapes, easier to braid, stores

later, smaller cloves, harder to peel). • Asiatics and Creoles sometimes have scapes.

Planting Time

• Fall-planting is best. • 9 am soil temperature 50°F (10°C) at 4” (10

cm) deep. We plant in early November. If the fall is unusually warm, wait a week.

• Softneck garlic can be planted in the very early spring if you have to (reduced yields). Give your seed garlic 40 days at or below 40°F (4.5°C) before spring planting, or the bulbs will not differentiate (divide into separate cloves).

Garlic emerges quickly in the fallRoots grow whenever the ground is not frozen

Tops grow whenever the temperature is above 40°F (4.5°C).

Growing in Winter• Get enough top growth in fall so garlic has a roaring start in

the spring, but not so much that the leaves cannot endure the winter.

• If garlic gets frozen back to the ground in the winter, it can re-grow, and be fine. If it dies back twice in the winter, the yield will be lower than it might have been if you had been luckier with the weather.

• When properly planted, garlic can withstand winter lows of -30°F (-35°C).

• If planted too early, too much tender top growth happens before winter.

• If planted too late, there won’t be enough root growth before winter, and you’ll get a lower survival rate and smaller bulbs.

Storing Seed Stock• Store at 50-60°F (10-15°C). Don’t

refrigerate.

• Avoid temperatures of 40-50°F (4.5-10°C) during the summer, as this causes sprouting before you are ready to plant.

• We have been carefully selecting seed stock for about 20 years now, and it does great.

• Cloves for planting should be from large (but not giant) bulbs and be in good condition.

How Much to Plant• Yield ratio about 1:6 or 1:7 with

hardnecks. • Makes sense - you are planting one clove

to get a bulb of 6-7 cloves. If you get 1:12 you are doing very well indeed.

• Divide the amount you intend to produce by 6 to figure out how much to plant.

• Single rows, 8 lbs (3.6 kg) of hardneck or 4 lbs (1.8 kg) of softneck per 100’ (30 m).

• Large areas 750-1000 lbs/ac (842-1122 kg/ha) are needed for plantings in double rows, 3-4” in-row (7.5-10 cm), beds 39” (1 m) apart.

• 3-9 lbs (1.4-4.2 kg) per person per year in the US.

Popping the clovesUp to 7 days before planting

Photo from Southern Exposure Seed Exchange

Popping the Cloves

• Twist off the outer skins, pull the bulb apart • With hardneck garlic, the remainder of the stem acts as a handy

lever for separating the cloves. • Don’t worry if some skin comes off the cloves – they will still grow.• Try not to break the basal plate of the cloves (the part the roots

grow from).

Sort: • good size cloves in big buckets, • damaged cloves in kitchen buckets, • tiny cloves in tiny buckets (planted for garlic scallions)• outer skins and reject cloves in compost buckets.

Pre-plant Treatments To prevent some pests or diseases

Stem and bulb (bloat) nematode: 1. Soak the separated cloves for 30 minutes in 100°F (37.7°C) water

containing 0.1% surfactant (soap).2. Or soak for 20 mins in the same solution at 120°F (48.5°C). 3. Then cool in plain water for 10-20 mins. 4. Or soak in 10% bleach water for 10 mins, warm water rinse.5. Allow to dry for 2 hours at 100°F (37.7°C) or plant immediately.

Fusarium: 6. Soak the cloves in a 10% bleach solution, then roll them in wood ash

(wear gloves). The wood-ash soaks up the dampness of the bleach and provides a source of potassium.

7. Add wood ashes when planting, or possibly dust the beds with more ashes over the winter. (Use moderation - don’t add so much that you make the soil alkaline.)

More Pre-plant Treatments

Mites :1. Separate the cloves and soak them overnight (up to 16 hours) in water. The long

soaking loosens the clove skins so the alcohol can penetrate and reach the hidden mites.

2. Optional additions to the water: 1 heaping tablespoon of baking soda and 1 tablespoon of liquid seaweed per gallon (around 8 ml baking soda and 4 ml liquid seaweed per liter).

3. Just before planting, drain the cloves and cover them in rubbing alcohol for 3-5 minutes, so the alcohol penetrates the clove covers and kills any mites inside. Then plant immediately.

Various fungal infections:4. Separate the cloves and soak them for 15-30 mins in water (optional extras as for

mites).5. Just before planting, drain the cloves and cover them in rubbing alcohol for 3-5

minutes.

Crop Requirements• Sandy or clay loam, very good

drainage, fertile soil, lots of OM, P and K important.

• Rotation: at least five years away from alliums.

• Full sun. • pH of 6.0-8.4, with 6.8 optimum.

Onion maggots thrive if the soil is alkaline.

• Compost or soybean meal at planting time. 30-60 #N/ac

• 1-2” (2.5-5 cm) of water per week during the growing season (not during the winter), until the leaves start to yellow and the bulbs start to dry down, when irrigation should be stopped.

When Foliar Feeding is WastedIf your garlic reaches 4 leaves before winter, forget about foliar feeding and side-dressing.

Reasons:1. It provides no gain in yield if the soil had adequate fertility at planting

time. 2. Foliar fertilizers tend to run off the waxy near-vertical garlic leaves,

unless you add a good sticker-spreader (soap). 3. Foliar feeding (or side-dressing with compost or organic fertilizers) is

wasted after the fifth leaf, and certainly after the bulb starts to enlarge. 4. In the South, spring is too late for foliar feeding, as garlic reaches a four-

leaf size before winter. 5. Don’t over-fertilize in the fall or growth will be too fast and tender to

survive cold conditions, and the storage life of the garlic will be reduced.

SpacingGive each plant 32 to 72 square inches (206 -465 cm2).

3” (7.5 cm) is too close. The shading of one plant by another reduces yield.

We like 5” (13 cm) spacing in the row, and 8-10” (20-25 cm) between rows, 4 rows in a 3.5-4’ (1-1.2 m) wide bed. That’s 40 in2 (258 cm2) each. We get plenty of 2 ½ “ bulbs. Many growers plant at 6” (15 cm) in-row.

Double rows and drip tape - you can run a length of tape and plant one row each side, with all plants 6” (15 cm) apart in all directions, and 40” (1 m) or less between drip lines and the pairs of rows.

Planting depth

Depth: 1.5-2” (4-5 cm) of soil over the top of the cloves in the South, and 3-4” (8-10 cm) of soil in the north. Avoid planting deeper than necessary, as any mold problems you have may get worse.

Planting depth in Michigan is 6” (15 cm). (Deeper planting helps prevent too much top growth and moderates the soil temperature.)

In Arizona, some growers set the cloves on the soil surface, then cover with 6” (15 cm) straw. This makes for a clean crop and an easy harvest.

Planting• Hardneck - plant the right way up (pointy end up)! Hardneck cloves with the

points down suffer a 30% reduction in yield. Softneck cloves can be planted any way up, so are easier for mechanical planting.

• Our method is to mark the bed with a row-marker rake, make furrows with pointed hoes, then lightly press the cloves into the furrows at the chosen spacing, using measuring sticks. After that we pull soil over the cloves using regular hoes or rakes, and tamp the soil down with the back of the tool.

• Some other growers who also plant by hand make a planting jig to make four or more holes at a time in loose soil, rather than make a furrow. Plant a clove in each hole and cover with the right depth of soil.

• If you can’t squat, or you are planting from the seat of a tractor, use a 3’ (1 m) length of pipe to drop the cloves into the furrows. Dropped from that height, through a tube wide enough for the garlic to tumble end-over-end, the cloves will land the way they need to be.

No-till PlantingThere were trials at Virginia Tech to develop no-till planting for garlic, planting in the fall into a frost-killed cover crop.

• Sorghum-Sudan hybrid, Lab-lab bean and Sunn hemp were planted in the first week of August in raised beds.

• When frost had killed the cover crops (10/24) the beds were rolled to flatten the crop residue

• Garlic cloves were planted 5-6” (14 cm) deep in holes made with a soil probe. All plots were given organic fertilizers.

• Some were covered with thick straw, which was always beneficial.

Disappointing results - no-till caused a 32-44% bulb loss, with Sorghum-Sudan by far the worst. So don’t re-invent the wheel. Speculation - the cover crop residues tied up the available nitrogen.

No-till where oats winter-kill:

Sow oats 4 weeks before garlic-planting date. David Stern in upstate New York successfully plants into oats that have reached 6” (15 cm) tall. He cuts slots through the oats with a disc-furrower and plants the cloves in the slots. The oats continue to grow until winter-killed, and they continue to protect the garlic. Timing is obviously critical and site-dependent. Can be harder to harvest from the “turf-like” soil. Wireworms could potentially be a problem, encouraged by grasses.

• Roll round bales of spoiled hay over our beds immediately after planting.

• Leave it all alone until late February,

• Start weeding (once a month for four months).

• In the South organic mulches keep the soil cooler once the weather starts to heat up. It is harder to add mulch after the garlic has started to grow.

• Organic mulches will protect the cloves from cold winter temperatures, and frost-heaving to some extent.

Mulching

Liberate trapped shoots!Free trapped garlic shoots from over-thick mulch, a couple of weeks after

mulching.

Garlic Scallions• To grow garlic scallions, save the smallest cloves

from planting your main garlic crop• Plant close together in furrows, dropping them in

almost shoulder to shoulder, just as they fall. Close the furrow and mulch over the top with spoiled hay or straw. • We harvest garlic scallions from early March, once

they reach about 7-8" (18-20 cm) tall,• They last till May, unless we need to use the space. • Loosen the plants with a fork rather than just

pulling. • Trim the roots, rinse, bundle, set in a small bucket

with a little water, and you're done! • Some people cut the greens at 10" (25 cm) tall, and

bunch them, allowing cuts to be made every two or three weeks. But the leaves keep in better condition if still attached to the clove. • Scallions can be sold in small bunches of 3-6

depending on size.

Weed control is importantWeeds can decrease yield by as much as 50%.

Kill the spring cool-weather weeds, then kill the summer weeds.

Weed control methods

• Without mulch: cultivate fairly frequently. Use tine weeders up until garlic is 6-8” tall. Then hillers will deal with the between-row weeds and some of the in-row weeds, but be careful not to cover too much of the foliage as this reduces yields. Could flame-weed.

• Take care when hoeing or cultivating and hand-weeding. Keep the leaves in good shape.

• Each leaf damaged or removed will cause about a 17% yield reduction for that plant.

Vinegar Weeding

Useful in controlling broadleaf weeds, but has no effect on grass weeds. It is possible to reduce labor by 94% using vinegar rather than hand-weeding, so if broadleaf weeds are what you get, this is a good solution. 2004 SARE Grant report by Fred Forsburg.

• 5 applications of 10% acetic acid vinegar spray during the growing season.

• Start when the garlic is 18” (46 cm) tall• Spray about every 10 days, from both sides of each row. • Wear a mask and gloves, long sleeves and long pants, this

strength of vinegar is caustic. • www.honeyhillfarm.com

Flame Weeding

• Flame-weeding can achieve as good results as hand-weeding using one-third of the labor.

• Can be used for relatively mature garlic, but young plants (four or fewer leaves) are too easily damaged.

• Direct the flame at the base of the plants, in the morning, when the plants are turgid.

• Don’t flame-weed if you have mulch!

Colorado State Specialty Crops photo

Diseases

The major diseases are mostly fungal: White Rot, Fusarium, Botrytis, Rust, Penicillium Molds, Purple Blotch, Powdery Mildew and Downy Mildew. Bacterial soft rots are also sometimes seen.

• Use pre-plant clove treatments to reduce disease. • Remove isolated sick plants as soon as you see them. • Always remove garlic debris from the field at the end

of the season, or till it in and plant a non-allium crop. In summer, soil biological life is very active, and soil organisms will quickly break down the debris.

Cold weather diseases• White Rot is most active below 75°F (24°C) and leads to yellowing and

dying of older leaves, tipburn, destruction of the root system and rotting of the bulb. This fungus can persist in the soil for 10 years, and requires assertive action to reduce the problem. A clever trick is to spray garlic extract on the soil when the temperature is 60-70°F (15-21°C) and you have no garlic growing. The fungal mycelium may grow and then die off in the absence of food. Several weeks later, garlic can be planted and will escape the rot.

• Rust shows up initially as small white flecks on the leaves, developing into orange spots. Favorable conditions include temperatures of 45-55°F (7-13°C), high humidity but low rainfall, and low light. Stressed plants are the most likely to be stricken. Infected bulbs may shrink, yellow and die. Once again, good sanitation and rotations are the organic approaches.

Hot weather diseases• Fusarium usually attacks plants that are under stress. (In our

garden it is the plants on the gravelly edge of the patch.) It grows during hot weather, with symptoms similar to White Rot, but slower to develop. Fusarium produces small brown spots on the cloves, yellowed leaves and stunted browned roots. The discoloration of the leaves spreads from the tips. The main organic approaches to controlling Fusarium are good sanitation (and pre-planting treatments) as well as fostering strong plant growth.

• Botrytis symptoms include “water-soaked” leaves, and can lead to bulbs rotting, sometimes during storage. This fungus grows best (worst!) in warm wet weather. Good airflow during growth, curing and storage, will reduce the chances of Botrytis problems.

PestsPests include nematodes, thrips, onion maggots, cutworm, armyworm, and mites. Weekly scouting is a good practice. Use pre-planting treatments against nematodes and mites.

• Caterpillars can be killed with Bt.• Nematode infestations show up as distorted, bloated, spongy leaves and

bulbs, perhaps with brown or yellow spots. Top growth yellows and may separate from the root system.

• Thrips are on the menu for lady bugs and minute pirate bugs. Farmscaping (planting flowers to attract beneficial insects that feed on pests) can work.

• Onion maggots: ground and rove beetles, birds and braconid wasps all prey on some life stage of the onion maggot. Beneficial nematodes can be effective against them. Rowcover can exclude the fly (mother of the maggots).

• Mites can eat the skins of the cloves, survive the winter and multiply all spring long, seriously damaging or even killing your crop. Use pre-plant soaking treatments.

Garlic Scapes

Garlic scapes are the firm, round seed stems that grow from hard-neck garlic, starting to appear 3 weeks before harvest, as the bulbs size up. If these are removed, the garlic bulbs will be bigger and also easier to braid, if you want braids from hardneck varieties. Contrary to ideas mentioned by some sources, leaving scapes in does not increase the storage life. Most people who remove scapes cut them where they emerge from the leaves. We prefer to pull ours, to get the most out.

Colorado State University Specialty Crops photo.

Harvesting Scapes• Two or three times a week, for three weeks in May. • Late morning is a good time to pull scapes (or early afternoon). The wound

heals quickly then, reducing the risk of disease, and the water-loss from the plant.

• Don't wait for the top of the scape to loop around, as they begin to toughen and reduce the final yield of the garlic.

• As soon as the pointed caps of the scape have cleared the plant center, grasp the round stem just below the cap and pull slowly and steadily vertically upwards. The scape emerges with a strange popping sound and you have the full length of the scape, including the tender lower portion.

• Enjoyable task - it's a stand-up job, and there’s a friendly competition to see who can get the longest scape. (Encourages everyone to perfect their technique.)

• Gather into buckets, with scapes upright, put a little water in the bucket.• Scapes are aligned, easy to bunch or cut up. Scapes sell in bunches of 6-10. • Store well in a refrigerator for months if needed. • 1 acre (0.4 ha) of hardneck garlic produces 300-500 lbs (136-226 kg) of scapes.

Pre-harvest prep• With hardneck garlic, scapes will start appearing about 3 weeks

before the bulbs are mature. (Day-length as well as accumulated degree days determines when scapes appear as well as when bulbs are ready to harvest.) This is a good time to be paying more attention to your garlic crop, and what better way than walking through pulling scapes?

• Take the opportunity to remove any diseased plants from the patch at the same time. Three weeks before the expected harvest, remove the mulch to help the bulbs dry down, and to prevent fungal diseases.

• In our rotation, the spring broccoli is usually next door to the garlic, and we move the old garlic mulch to the broccoli to top up the mulch there. It helps us stay on track with getting the broccoli weeded too.

Determining when to harvestGarlic is ready to harvest when the sixth leaf down is starting to brown on 50% of the crop. See Ron Engeland's Growing Great Garlic.

Harvesting too early means smaller bulbs (harvesting way too early means an undifferentiated bulb and lots of wrappers that then shrivel up). Harvesting too late means the bulbs may "shatter" or have an exploded look, and not store well.

Usually it's 6/7-6/14 for harvest of our main crop of hardneck garlic, but it has been as early as 5/30, and as late as 6/18.

Cut across hardneck garlic – airspaces around stem show maturity

Music German Red

Mechanical HarvestColorado State University Specialty Crops

photo Use a tractor-mounted undercutter to loosen the bulbs, or a root-harvester to completely dig them up. Sub-soilers, European leek harvesting machines or homemade undercutters fashioned from an old snow plow blade bent into a rectangular shape, have all been used.

Manual Harvest

• Use digging forks to loosen the soil – lift, don’t pull. Stressing the necks will not improve the curing.

• In drought years use overhead irrigation the evening before, to loosen the soil enough to harvest without damage.

• Treat the bulbs like precious sun-sensitive eggs! Bruised bulbs won't store well, nor will sun-scalded ones. It’s better not to wash them, as drying is what’s needed. Shake off the soil, without banging the bulbs.

Avoid cooking your garlic!We harvest into buckets to keep the bulbs shaded. Others might use crates. If it’s hot, get the garlic out of the field quickly, hang it up and get it drying, (indoors!) Don’t let garlic get above 121°F (49°C) as it will start to cook.

Despite looking a lot yellower than “5 green leaves”, this 2012 crop was not shattering.

Garlic harvest gets fast follow-upImmediately after the harvest we till the old garlic area and sow buckwheat and soy. We have about six or seven weeks before we'll use these beds to sow our fall carrots at the very beginning of August.

Setting garlic to cureThe indoor job of hanging the garlic to cure as it comes in from the field is popular when it is hot outside. It takes us several morning shifts to get our 4200 row feet (1280 m) of garlic harvested and hung up.

Some growers tie the plants in loose bundles of about 8-12 plants and hang the bundles under cover. If you can size the bunch so it ends up around one pound (0.5 kg) in weight, you may save yourself a task later.

Whatever method you are using, get the garlic spread out immediately. Don’t leave it in plastic containers where the heat and moisture will incubate fungi!

Pic of garlic drying on floor

Cure for 2-4 weeks. We hang our garlic in nylon netting around the walls of a barn. The netting has a 2" (5 cm) diamond mesh.

Snowfencing (slats and wire, or the plastic kind) can also be used to hang garlic.

Or you can make horizontal racks, and lay the garlic on top.

To braid softneck garlic, start braiding within the first week of curing, before the leaves become too brittle. You’ll also need to clean your garlic.

Using netting

We thread a bulb in each diamond, by bending the tops of the leaves and feeding them through the space. We take a section of netting and work upwards in rows, back and forth, covering the walls in garlic. We use fans to move the air, which you should consider if your climate is also humid.

Snipping and Sorting

Test the curing garlic by rolling the neck of a few sample bulbs between finger and thumb. If it feels dry, rather than moist, it's ready.

Use scissors to cut off the roots close to the bulb and the tops ¼ - ½ " (0.5-1 cm) above the bulb. Some growers brush mud off with toothbrushes. We find enough dirt drops off during storage to save us this tedious task.

Selecting seed garlic

Measure the bulbs and assess which are good for seed.

We save for seed all bulbs 2-2.5" (5-7 cm) in diameter, with an even shape and cloves that are tight together, not opening up.

Some growers use jigs with two foam-lined battens tapering towards each other on a board to measure sizes.Photo: Colorado State University Specialty Crops

Sorting garlicDon’t just save all the biggest bulbs for seed - they tend to be uneven ("rough") in shape and quality, with cloves of all sizes.

Storage

• Our seed garlic goes on a high shelf in the shed, at quite variable temperatures, and does fine until early November when we plant it. The ideal storage conditions for seed garlic are 50-65°F (10-18°C) and 65-70% relative humidity.

• Don’t refrigerate - prolonged cool storage results in “witches-brooming” (strange growth shapes), and early maturity (along with lower yields).

• Storage above 65°F (18°C) results in delayed sprouting and late maturity.

• The eating garlic is stored in a dry, coolish basement at 60-70°F (15.5-21°C) over the summer. In late September we move our eating garlic to the walk-in cooler at 35-38°F (1.5-3°C) to make space available for the winter squash. At 32°F (0°C) it will store for 6-7 months. It does not freeze until 21°F (-6°C).

• Avoid the middle temperature range of 40-56°F (4.4-13°C), as this encourages sprouting.

Kilarney hardneck (SESE)

Music hardneck (SESE)

Siberian hardneck (SESE)

German Red Hardneck (SESE)

Italian softneck (Artichoke type) (SESE)

French Red Softneck (SESE)

Silverwhite softneck (Silverskin type) (SESE)

Inchelium Red Softneck (Artichoke type) (SESE)

Polish White Softneck (SESE)

Lorz Italian (SESE)

ResourcesATTRA, Organic Garlic Production, attra.ncat.org/attra-pub/summaries/summary.php?pub=29

The Garlic Seed Foundation, garlicseedfoundation.info An organization of growers and eaters. Website lists suppliers and resources, including the ARS Germplasm Resource, which supplies small amounts of plant material to growers. Extensive library and information on building your own harvesting equipment.

Dr Gayle Volk’s Garlic DNA Analysis, garlicseedfoundation.info/allium_sativum_DNA.htm

Nematodes, garlicseedfoundation.info/bloat-nematode-new-york.htmgarlicseedfoundation.info/images/nematode-cce.jpg

Gourmet Garlic Garden growing instructions, pests and diseases, growing in the South, and more, gourmetgarlicgardens.com/index.htm

Fred Forsburg has designed a tractor-drawn planting platform www.honeyhillfarm.comVinegar to kill weeds: 2004 SARE Grant report by Fred Forsburg

Colorado State University Specialty Crop Garlic Project,specialtycrops.colostate.edu/scp_exp_demo/garlic_2004_spce_flme_scpe.htm

Growing Great Garlic, Ron Engeland, 1991, Filaree

Sources for SeedGourmet Garlic Gardens, gourmetgarlicgardens.com/index.htm 325-348-3049, 73 varieties

Filaree Farms, WA, filareefarm.com 509-422-6940,over 100 varieties

Territorial Seeds, OR, territorialseed.com800-626-0866, 27 varieties

Southern Exposure Seed Exchange, VA, southernexposure.com 540-894-9480, 17 varieties

Irish Eyes Garden Seeds, WA, irisheyesgardenseeds.com 509-964-7000 or 509-925-6025, 19 varieties

Growing Great GarlicPam Dawling

Twin Oaks Community Central Virginia

Author of Sustainable Market FarmingSustainableMarketFarming.com

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