Green Man Publishing

Garlic

Allium sativum

Introduction: Garlic originated in the Caucasus region of central Asia and is thought to be one of the first cultivated plants (it no longer even occurs as a wild plant). It has been prized as a culinary flavoring for over 7000 years, having been cultivated by almost every ancient civilization, from the Chinese, Indians and Egyptians onwards. China is now the worlds biggest producer, growing something like 70% of the total world crop.

Ease of growing: Garlic is a fairly easy crop to grow and I find it one of the most satisfying. Harvesting the garlic crop is one of the highlights of my gardening year. 

Garlic is very productive and it is easy to grow enough for a whole year. It is also fairly easy to store and some varieties can keep for up to 10 months.

Crop value: Garlic isn’t hugely important from a nutritional standpoint because it is only eaten in small quantities, but it is extremely important from a culinary viewpoint. It is second only to the onion in importance as a kitchen flavoring. No serious cook could conceive of not having garlic on hand.

Nutritional content: Garlic contains so many valuable phytochemicals (including allicin, ajoene and allyl sulfide) that it is an important medicine / food. It has anticarcinogenic, antioxidant, antifungal, anticlotting, antiseptic and antibiotic properties (and probably a few more too).

Garlic has so many beneficial qualities that there has been a lot of hype in recent years about its value as a medicine / food (I refuse to use the word nutriceutical) and countless commercial preparations are available. However a lot of its beneficial chemicals are quite fragile so eating them as a food is more effective than swallowing them in a manufactured product.

You can maximize the beneficial qualities of your garlic by letting it sit for a while after chopping


Garlic contains about 670 calories per pound. I’m not quite sure why I’m telling you this, as I can’t imagine anyone has ever eaten a pound of garlic at one time!

About Garlic  

Planning facts
Hardiness: hardy
Growing temp: 45 (55 – 75) 85°F
Days to harvest: 90 – 220 days
Plants per sq ft: 4
Plants per person: 10 – 15
Height 12 – 24˝
Width 6 – 12˝  

Planting Fall: 8 – 10 wks before first frost
Spring: 4 – 6 wks before last frost  

Harvest facts
Harvest period: 2 – 3 weeks
Yield per sq ft: ¾ – 2 lb
Yield per plant: 2 – 4 oz  

Climate: Garlic originated in central Asia with its cold winters, cool springs and warm dry summers. It needs warm days (cool nights are fine) for best growth. Too much heat (above 95°F) can hasten maturation, which isn’t good as it means the plant has less time to store food and so results in smaller bulbs. Rain while the bulbs are maturing isn’t good either.

Garlic is very hardy and can tolerate temperatures down to 0°F or lower. If the soil doesn’t freeze, its roots will continue to grow right through the winter. The tops will also grow whenever the temperature is above 40°F, in fact they grow best in fairly cool conditions.

Hardneck varieties are hardier than the softnecks and so a better choice for colder areas. The softnecks are more suited to mild winter areas. Most commercial garlic is the softneck type, grown in central California with its mild winters, mild springs and warm, dry summers.

Soil

pH 5.5 (6-6.5) 7.0

Garlic will grow well enough on poor soil, but the bulbs won’t get very big. For big beautiful bulbs it needs a light, rich, deep, moist, well-drained loam with lots of organic matter. Drainage is important for this over-wintering crop, as the roots may rot if they stay wet and cold for too long.

Soil preparation: Garlic sends down roots 2 feet or more, so the ideal soil is deep, loose and friable. It doesn’t like compacted soil, so if the soil is at all heavy or compacted, then double digging and incorporating organic matter will help. Raised beds are also beneficial as they help to ensure deep soil and good winter drainage (which is important).

Incorporate 2˝ of compost or aged manure into the top 6˝ of soil, along with a source of potassium (wood ashes) and phosphorus (colloidal phosphate). Garlic has a particular liking for sulphur.                                                                                                             

Garlic does well following a recently incorporated summer green manure crop, as it benefits from the newly released nutrients. You might even plant a crop of buckwheat specifically to fertilize a following garlic crop. Wait two weeks for the crop to decompose before planting the garlic.

Don’t overdo the fertilization for garlic, as it can make the bulbs less flavorful.

Planning

Where: Garlic needs full sun, the more the better. It doesn’t tolerate weeds very well, so try to choose a spot that doesn’t have a lot of them.

Crop rotation: Don’t plant garlic in soil where any Allium (garlic, onion, shallot, leek) has grown within the last 3 years.

When: The most important factor in growing good garlic is planting it at the right time.

Fall: In places where garlic will survive the winter it does better and gets larger when planted in fall. This gives it plenty of time to put on vegetative growth and store food before the long days of the following summer trigger bulbing.

In mild climates, set out your cloves from August onwards (at least 2 months before the first frost date). You want the plants to be well established before the onset of cold weather.

You can also plant garlic in fall in colder areas (until November). They won’t make any top growth, but their roots will grow and give you an early start in spring. The bed should be mulched with 4 – 6˝ straw to protect the cloves from frost and prevent heaving. When the coldest part of the winter is over (early spring) you should remove the mulch to allow the soil to warm up.

Spring: In areas with very cold winters, fall planted garlic may not survive outside and in such places it is often planted in spring, 4 – 6 weeks before the last frost. It can go in the ground as early as early as February if you protect it with cloches.

Don’t wait too long in spring to plant your garlic, or you may run into a problem with lack of chill. The dormant cloves and / or young plants must be exposed to a period of cold weather (6 – 8 weeks below 50°F) before bulbing can occur. If they don’t get this the cloves will simply get bigger, rather than dividing into the familiar bulbs. These are known as “rounds” and can be eaten (though they aren’t very big) or left in the ground for another year.

Spring planting works okay, but isn’t usually as productive as fall planting.

Planting

How: Garlic is propagated vegetatively from individual cloves. Gently break open the bulb, without bruising the cloves inside (you don’t want them to lose their protective skin). Do this just before planting, as separating the cloves may initiate root growth.

Some people say larger cloves make larger bulbs. Others say it doesn’t matter much what size the clove you plant (within reason), the final bulbs will be about the same size. I say if you bought bulbs to plant, then plant them. Do you care if some of the resulting bulbs are slightly smaller than others? If you have plenty of planting material, you might use very small ones for growing garlic greens.

Plant the cloves 2 – 3˝ deep (1˝ in mild areas), making sure they are upright. This means planting them pointed side up and flat side down (planting upside down does not help). If the soil is very loose you can just push the clove down into the soil, but if it is hard the ensuing pressure may damage the base of the clove. In such circumstances you should loosen the soil before planting.

Sometimes the newly planted cloves will be dug up by cats using the freshly planted bed as a litter box. The best way to prevent this is to lay a piece of wire fencing on the bed for a few weeks. The sprouts can emerge through this easily, but it prevents digging.

Spacing:

Beds: Space the plants 4 – 6˝ apart, in short offset rows across the bed. Use the closer spacing in very fertile soil and the wider spacing in poor soil. If you want to be able to hoe between the rows, make the rows slightly wider (8˝) apart.

Rows: Space the plants 4 – 6˝ in the row, with 15 – 24˝ between the rows.

Bulbing: As with the related onions, bulbing is determined by day length. Bulb formation is triggered by long days and once the right day length comes along, the plant will form a bulb, no matter what size the plant. Once bulbing starts, leaf growth comes to a halt.

Bulbing is also affected by temperature, soil fertility, plant size and vigor, but to a lesser extent.

The bulb consists of specialized storage leaves. Bulbing occurs when the plant stops producing new leaves and starts to store food in the leaves it has. This causes their bases to expand, which creates the bulb. When the bulb is mature, all of the food has gone from the rest of the leaves, so they wither, fall over and die.

For large bulbs you want maximum leaf growth before day length triggers bulb formation. In ideal conditions the plants may get two feet tall. Poor leaf growth means small bulbs, with small cloves that are so tedious to peel they often don’t get used (don’t throw them away though, see Green Garlic below).  

Care

Weeds: Garlic only has a few strap-like leaves and can’t compete with weeds very well, so it’s important to keep it well weeded at all times. This is all the more important as the plants are in the ground for a long time (parts of two growing seasons). The roots are shallow, so hand weeding is preferable to hoeing.

Water: This is another critical factor in growing good garlic. The plants need to have a steady and constant supply of moisture when putting on leaf growth and bulbing up. Do not allow the soil to dry out at this time. At the same time you don’t want the soil to be too wet, as this can encourage fungus disease, so don’t over-water.

About 2 – 3 weeks before the plants are ready to harvest, you should stop watering, to allow them to dry out. This hastens maturation and starts the curing process.

Mulch: I like to lay down a 2 -3˝ straw mulch after planting, to conserve moisture, keep the soil cool and suppress weeds.

In cold climates a thick mulch is used to protect the cloves over the winter. This should be removed in early spring to allow the soil to warm up. When the soil is warm you apply a thinner mulch to suppress weeds and conserve moisture.

Fertilization: Garlic isn’t a very hungry plant, but it needs a steady supply of nutrients for best growth. Young plants need an adequate supply of nitrogen, so you may want to feed them in spring while the soil is cool and not much nitrogen is readily available.

If your soil isn’t very fertile it is a good idea to give them a regular foliar feed of compost tea or liquid kelp. Start this when the plants are 3˝ tall and repeat every 2 – 3 weeks during the growing season (stop about a month before bulbing starts). If you don’t want to do this, you can simply feed them once in spring when they start growing vigorously. They need micronutrients as much as NPK.

The yellowing of some leaf tips is quite normal in garlic; it doesn’t necessarily indicate any kind of nutrient deficiency.

Problems

Bolting: Hardneck garlic usually send up a scape (flower stalk) in late spring, just before it starts to bulb up. Many people consider this to be undesirable and remove it to prevent it using energy that could be used for enlarging the bulbs. However some growers say it is best to leave it on as the bulb stores better (even if it is very slightly smaller).

One good reason to remove the scape is that it is edible (don’t throw it away). In Asia these are highly prized as food and special varieties are grown to produce them. See Scapes below for more on this.

Softneck garlic doesn’t produce scape routinely, though they may do so if stressed. If these start to bolt you should remove the scape promptly.

Pests and diseases: Garlic is generally free of most pests and diseases, though it is more afflicted in cool wet climates. It is occasionally attacked by onion maggots (a relative of the dreaded cabbage root fly/maggot) and thrips. Of course gophers will eat it too (plant by plant, right down the row, if given the opportunity).

Harvesting

Garlic is propagated vegetatively, so all of the cloves of a variety are genetically identical. The ultimate size of a bulb is determined by timing, growing conditions and to a lesser extent by variety (some naturally get larger than others).                                                                                            The size and number of cloves in a bulb is determined by the variety. Sometimes a bulb may have a small number of large cloves and sometimes it may have a large number of small cloves.

When: Garlic is harvested when half of the lower leaves have turned yellow (there should still be 5 or 6 green leaves). At this time you should be able to clearly see the swollen bulb when you move the mulch aside. Pull up a few random bulbs and inspect them carefully before harvesting all of it.

If garlic is left in the ground too long all of the leaves turn brown and the over-mature bulbs may start to split open. This may not look very nice, but doesn’t affect its edibility. These might not store as well though (they may dry out faster), so should be used first.

How: If your soil is very loose often you can simply uproot the plants by pulling on the tops. If the soil is very firm, you will have to loosen it with a fork first. Garlic bruises easily, so handle it carefully at all times and never throw it around.

Don’t leave the bulbs on the ground in the sun for too long, as they may get cooked. They then turn a translucent yellow and are ruined.

Curing: Newly harvested garlic should be cured at around 70°F before storage. This not only lengthens its storage life but also improves its flavor (newly harvested garlic may be somewhat bitter).

If the weather is dry, you can cure the bulbs by leaving them in a shady place for a week or two. If it’s wet, you will have to cure them Inside (the greenhouse is a good place, as it’s dry and warm). Once they are dry the leaves don’t smell of garlic very much.

The dry bulbs are prepared for storage or sale by cutting off the shriveled tops (leave about 2˝) and trimming the stringy roots (to ½˝). They are also cleaned by removing any discolored outer wrapper layers. If you have several varieties that look similar you might cut the stems of each variety to different lengths, to help identify them.

If you want to make garlic braids, save the bulbs with the best tops (don’t cut them off of course).

Storage: The bulbs must be thoroughly dry before storing them in a cool dry place, with 50 – 60% humidity and good air circulation. If the bulbs are to be used fairly quickly, they can be stored at 50 – 60°F. For longer-term storage (and for the bulbs that will be re-planted in fall) they should ideally be kept at 35 – 40°F.

Store the bulbs in wooden boxes, mesh bags, or the traditional garlic braids. It is tempting to hang these attractive braids in the kitchen, but it is usually too warm and dry there. When stored above 70°F some of the bulbs may dry out before you get around to using them.

In the kitchen its best to keep garlic in a terracotta garlic keeper or a doubled brown paper bag. This ensures it has the high humidity necessary to prevent it drying out.

Different types of garlic have different storage properties. The softneck types store better than the hardnecks.

Seed saving: Garlic doesn’t produce viable seed, so it is propagated vegetatively from the same cloves you use for cooking. Simply save some of the bulbs for re-planting at the appropriate time. These must be stored carefully though, otherwise they may dry out, or sprout prematurely. You can’t leave the bulb in the ground of course, because it will eventually start to grow again and form a crowded cluster of plants.

If you use the same strain for long enough, it will eventually adapt to your climate.

Unusual growing ideas

Containers: Garlic is a fairly compact plant and can do well when grown in a container. Just make sure it is big enough – at least 12” deep and that you use a good potting mix. The most difficult thing about growing garlic in a pot is that cloves are planted in fall, so will need attention for quite a while. The most important thing is to not let the soil dry out too much.

Bulbils: You can grow garlic from the bulbils that are sometimes produced on the flower umbel (head), but you won’t get mature bulbs for two years. Some types produce these more readily than others (notably the Asiatics and turbans)

Green garlic: In China a lot of garlic is planted for use in the green stage. Any surplus, or unusually small cloves (such as the aforementioned ones that are too small to peel) can be planted like green onions in a couple of square feet of bed. Single leaves can be cut off from the bulbs as needed (they will produce more). The whole young plants are also eaten. If you overlook a bulb and it sprouts in the garden, you can use the multiple stems in the kitchen.

Scapes: In China and Japan when a bulb bolts it is considered to be an opportunity, rather than a loss. The scape (flower stalk) is highly prized and constitutes an extra (and early) crop from the maturing bulbs. They are cut off as they emerge and the bulb continues to mature. In Asia they even have special varieties that reliably bolt, but still produce good sized bulbs.

Varieties

There are over 400 varieties of garlic, which may come as a surprise if you are only used to seeing the big white bulbs in the supermarket. Apparently a lot of garlic varieties came from the Soviet Union after 1989, which is why there are now many more varieties than were previously available. You can buy many strains by mail order, while a few may be available in local retail outlets. You should only need to buy a variety of garlic once, as it’s easy to save bulbs for next year.

You can grow garlic from cloves purchased in a supermarket, but it will probably be a softneck that is adapted to the California (or Chinese) climate. You will do better with locally grown bulbs from a farmers market, as they should be of a variety that does well in your area. When buying bulbs intended for food use, you should be aware that some diseases can be spread vegetatively in the cloves.

The kind of garlic you choose to grow is usually dictated by your climate or taste preferences. You should also think about their storage properties. You don’t want all of your garlic to be a variety that doesn’t store very well.

There are two main types of garlic, but they are divided into several groups.

Hard neck types (Ophioscordon ssp)

These get their name from the distinctly woody flower stalk which goes through the center of the bulb. They don’t usually get as big as the softnecks and have fewer wrapper leaves and fewer (but bigger) cloves. The latter is a good thing if you are growing in poor soil, because even small bulbs will produce a few good sized cloves.

Hardnecks are better suited to colder northern areas than the softnecks (in fact in very warm areas they may be hard to grow). They are divided into 3 main groups.

Rocambole

These varieties usually have thinner wrapper leaves, purple streaks and aren’t very white. They usually produce 8 – 10 cloves, arranged radially around a woody scape. They are some of the best flavored and most pungent garlics, but many don’t store for very long (about 6 months). The scape does a double loop as it emerges. They like cool winter and spring weather for best growth. They are hardier than the porcelain types.

Carpathian, German Red, Killarney Red, Spanish Roja.

Porcelain

These beautiful garlics have thick papery white or purple wrappers, usually containing a small number (4 – 6) of large cloves (which means you need to save more bulbs for replanting). They have a rich strong flavor (often hot) and store well (8 months or more). They do best in the north, but can be grown in most places. They are considered the best varieties for medicinal purposes.

Georgian Crystal, Georgian Fire, Music, Northern White, Romanian Red.

Purple stripe

These types have thick white wrappers with distinctive bright purple stripes (color intensity varies with growing conditions). The scape usually makes a three quarter loop, not quite making it all the way around.

They have very good, often complex, flavor (they are a favorite for baked garlic) and aren’t very pungent. They produce a small number (5 – 6) of large cloves and store for about 6 months. They are hardier than the porcelain types

The purple stripes may be sub-divided into three separate groups.

Standard Purple Stripe

Belarus, Chesnok Red, Persian star

Marbled Purple Stripe

Bogatyr, Gourmet Red, Siberian

Glazed Purple Stripe

Brown Tempest, Purple Glazer

Weak bolting hardneck types / softnecks

These were once thought to be softnecks, but now they are considered to be a separate group. This group contains some of the most interesting and unusual types.

Asiatic

These sometimes send up scapes in spring and sometimes not. This does an inverted U as it emerges. As the name suggests they were developed in Asia. They usually contain from 9 – 12 cloves. The flower umbel may produce a few medium sized bulbils that can be eaten or used for propagation.

Asian Rose, Asian Tempest, Korean red, Sonoran

Turban

These are called turban garlic because the large flower umbel somewhat resembles a turban (these produce a lot of small bulbils that can be used for propagation too). These often have good color and strong flavor, especially when raw. They are earlier, produce less cloves (only 6 or so) in a bulb and don’t store as well as other softneck types. They do well in dry climates.

China Dawn, Chinese Purple, Shandong, Tzan, Xian, Chinese Pink (early).

Creole

These are sometimes considered to be a separate group and sometimes included with the softnecks. They are the least common type of garlic and are still rare in most areas. They originated in Spain and southern France and are some of the best types to grow in warm climates (zone 7 – 10). They are quite tough and tolerate adverse growing conditions better than most types. They usually have very good flavor and are some of the best for eating raw. They also store well. Their biggest drawback is that they still quite hard to find

Ajo Rojo, Burgundy, Creole Red, Cuban Purple, Pescadero Red, Spanish Morado

Soft neck types

(Sativum ssp)

These don’t have the hard scape of the hardnecks, hence they are known as softnecks. They are the type of garlic commonly sold in supermarkets. They grow well in mild climates, which is why most American garlic is produced in central California. They often do well when planted in spring.

Softnecks store better than the hardnecks and have more cloves (12 – 20), with larger ones on the outside and smaller ones in an inner cluster. This means the bulbs need to get to a good size to produce reasonably sized cloves.

Artichoke

This is the type of garlic most often seen in supermarkets. These varieties are less temperamental than other types and so easier to grow (probably the easiest) and can get quite big. They have a soft central stalk and a large number of cloves (12 – 20), They store quite well. Their flavor varies a lot, some are mild and some are quite pungent.

California Early, California Late, Early red Italian, Inchelium Red, Italian Late, Polish White

Silverskin

These are the best keeping varieties (10 months or more) and have soft pliable tops, which make them the best for braiding. They are easy to grow, fairly late and have a stronger flavor than the artichoke types. The wrappers are white, though the cloves may be colored. They don’t get as big as the artichoke types, but have more cloves. This can be a problem if the bulb isn’t very big, as many of the cloves will be small.

Mexican Red, Mild French, Nootka Rose, Silverskin.

Kitchen use

Garlic doesn’t develop its characteristic flavor until the cell walls are ruptured. This releases as enzyme called alliinase which converts the alliin in the cells into the yummy diallyl thiosulphinate we all love.

The flavor of garlic varies according to how it is prepared. Many cooks insist that it should be chopped for best flavor. They say you should never crush it in a garlic press.

Green garlic: In China they don’t just eat garlic cloves. They eat the whole plant; young leaves, young plants, flower stalks. These can be used in the same ways as green onions.

Garlic soup  

You have to try this, it’s a variation of the soup that earned me a marriage proposal. Not in any way pungent or harsh, it is rich and delicious. I believe it originated in Provence.  
2 bulbs (not cloves) garlic peeled and chopped
4 tbsp olive oil
8 cups water
3 potatoes cut into small cubes
3 celery stalks (chop finely)
3 carrots sliced finely
1 tsp chopped parsley
1 tsp dried basil
1 bay leaf
Salt and pepper  

Saute the garlic in the oil for a couple of minutes and then add everything else. Simmer for about 45 minutes until the full flavor develops. It should be eaten immediately as its flavor starts to deteriorate if left for any
length of time. Unlike many soups it does not taste better the next day.