• Jere Folgert

Those Damn Weeds!

Updated: Feb 18

Tips for Effective Weed Control


Garlic has a long growing season and this gives weeds ample time to grow and steal precious resources from the garlic plant. It's hard to have compassion for weeds, but they're just plants growing in places where they're not wanted. To tackle them effectively without resorting to toxic chemicals, you need some hard-hitting strategies. Fortunately, there are plenty of tips and tricks that will help you get rid of these leafy invaders naturally. An effective weed management plan can increase garlic yields and bulb size. We'll review a variety of methods that can be used to control weeds.

Garlic do not Like Weeds

Weeds have powerful intentions: to reproduce and spread as far and wide as possible. Compound that statement with the fact that weed seeds can live for a number of years. Every square foot of your garden contain hidden weed seeds, but only those in the top inch or two of soil get enough water and light to trigger germination, depending on the species and whether the seed is exposed or buried beneath the soil surface. Understanding weeds and the strategies to keep them away from your garlic, will help your well-groomed garlic reach their full potential.

Weed Quotes, Garlic, Seed Garlic
Weed Quotes

Award Winning Short Film (Weeds)

Garlic plants do not like to compete for food and water. Ideally, garlic should grow in a weed-free environment for the entire growing season. Weed control is important -Weeds can decrease yield by as much as 60%. When removing weeds it is critically important not to damage the garlic plant - especially the garlic roots. Garlic roots are relatively shallow and can be damaged easily with a sharp blade, garden hoe, tiller, shovel or garden fork. Some organic garlic growers find that they need to remove weeds every two weeks. Weeding often and removing as many annual and perennial weeds as possible will help garlic plants flourish and reach full potential. One of the challenges with garlic is due to the fact that the narrow leaves do not effectively shade the ground, even at a mature stage.

Prevention of Weeds

Weed Prevention focuses on keeping new annual and perennial weeds out of your garlic patch and preventing the further spread of weed seed or perennial plant parts. Halting the introduction of weed seed to the soil can be particularly critical. One method of preventing weeds is to remove them or destroy them before they flower and release weed seed. This prevention strategy can focus on both the garlic plot and the area surrounding the garlic plot. If necessary, weeds may need to be removed from the field by hand before they produce seed. Weeds can also be introduced into fields through manure, compost, straw, animal feed, contaminated crop seed, or other materials such as hay. Did you know that some garlic growers confuse the difference between hay and straw? Hay is basically grass, grown to proper height, cut at the peak of nutrition, dried, bundled, and stored. Straw is the hollow, bare stalk remaining after a seed head, such as wheat or barley has been harvested. Use straw, not hay for mulch!

Advantages of Weeding? The Power of Observation!

At the GroEat Garlic Farm, weeds are often thought of as the enemy. The weeds, "force" us into the garden. The oldest way to tackle the problem is walking into your garlic plot and manual pulling; Walking each row, looking at virtually each plant. Sure, it is labor and time consuming. But, just the act of spending lots of time in your garlic patch has advantages. Observation forces us to take a closer look at what is happening in the garden. And if we take notes and photos, these recorded observations can help us by providing a chronicle of events over time. Chronological-Photo Records are a powerful way to document a garlic patch for future plantings. A set of garden notes and photos can greatly increase our knowledge base on the garlic-growing process. Both of these are extremely valuable as we learn more about the growing process and stages of garlic. When do the garlic scapes appear? What time of the year do certain weeds appear? What differences are observed between different garlic cultivars? We begin to identify garden problems at a very early stage, and we have notes that can be referred to in the future for planning and dealing with seasonal changes in the garlic plot. Thank you weeds, for forcing us to spend time in the garlic garden.

(Field Observations of Garlic Taken While Spending Time in the Garlic Patch)

Weed Control Methods

Open soil, wind, sunlight and rain all work together to help weeds flourish and thrive. It is virtually impossible to create a weed-free environment. Without intervention, over time, weeds will take over. But, by being diligent and following a few weed-control strategies, we can keep most weeds from robbing our garlic of precious water, nutrients and resources. Anything that reduces weed seed pressure will be advantageous. Here are a few methods that can be used to minimize weeds in your garlic patch.

1. Crop Rotation With Cover Crops

Cover crops can help suppress weeds, help increase water quality and reduce nutrient runoff and leaching during non-cropping months. Cover crops can provide a variety of benefits to the crop when used in crop rotations, especially if they are grown in the fall prior to planting garlic. Cover cropping can provide some weed control by competing with weeds for light, moisture, nutrients, and space. The denser the cover crop and greater the biomass, the greater the impact on weeds. Despite potential benefits, physical and chemical effects from cover crops may not provide adequate weed control. If cover crops become established quickly, they will suppress weeds, essentially suffocating them and aggressively using nutrients and water. Vigorous growth of the cover crops provide complete ground cover and are competitive with weeds. The biomass of the cover crop should be allowed to break down in the soil before planting garlic. Possible cover crops for garlic (field rotation) include Alfalfa, Hairy Vetch, Buckwheat, Red Clover and oats. Oats will grown and freeze down, die and become nutrient-rich mulch for the garlic. Garlic growers have observed that beans and peas can become stunted by garlic. Cover crops can help control weeds, reduce wind and water erosion, help loosen compact soil, add organic matter and nutrients to the soil. Cover crop biomass can increase pressure from certain diseases and insect pests.

(Clover Cover Crop)

2. Solarization of Soil

Soil solarization (also known as biosolarization) traps sunlight beneath a layer of clear plastic, and this heat can reduce weed seeds. This chemical-free method of sterilizing soil is achieved by raising soil temperature by covering it with thin clear plastic. The heat can also remove the entire structure of perennial weeds, including roots. The sun heats the soil to temperatures that kill bacteria, fungi, insects, nematodes, mites, weeds, and weed seeds. This is referred to as Thermal Killing. Thermal killing is effective because intense heat builds up from the sun. To solarize soil, begin by clearing the area of plants and debris. Next, water the soil deeply until it is wet. If you have compost, add compost and/or aged manure to the area. Next, drape clear plastic tarp(s) tightly over the entire area to trap the heat from the sun in the soil. To keep the plastic from blowing away, bury the plastic edges in the soil to trap the heat. Leave the plastic in place for at least one month in the hottest part of the summer before removing the plastic. The compost and manure encourage growth of heat loving microbes that produce organic acids from fermentation. While these acids may be deadly for pests, they are relatively non-toxic to humans. Solarization of soil shows promise against many North American weeds. Tarping is also effective and popular among small-scale growers. Solarization effectively controls seedlings though solarization may not be effective in killing seeds with harder seed coats.

(Soil Solarization Film)

When should solorization be used? Plan to solarize soil according to planting time: plastic must remain in place for a minimum of a month. Best results occur when garlic is planted immediately after removing the plastic. Instead of removing the plastic, holes can be burned into the plastic (using a blow torch) and garlic cloves can be planted directly into the holes. Because solarization requires a summer fallow (sometimes called fallow cropland, is cropland that is purposely kept out of production during a regular growing season), it works best with a fall-planted crop such as garlic. Solorization could be started in early July and allowed to stay in place until late September - just before garlic is planted in the fall.

3. Repetitive Tilling and Deep Plowing

Converting a never-before-planted field into a garlic patch can be a lot of work. Deep plowing and repetitive tilling is method that has some advantages - but also has disadvantages. Tilling creates a medium that is easier to plant and also creates an environment where organic matter is can be broken down to its primary elements. Tilling is like mixing the ingredients before baking a cake. The benefits of tilling include aerating the soil and making it light and fluffy. Garlic loves light and fluffy soil. The tines on a tiller also cut, chop and kill weeds. Tilling also churns and mixes soil, organic compost, fertilizers, and sulphur into the soil.

Begin by mowing the area that will become the new garlic patch. The first tilling will incorporate vegetative biomass (weeds and plants) into the soil will bring dormant weed seeds to the surface where they can germinate. This is good news. Weed seeds can remain dormant for a very long time. Keep a close watch on the newly tilled plot. You'll see new weeds sprouting in only a few weeks. This is good news. Tilling every few weeks for the entire spring and summer will eventually kill many of the weeds by disrupting their growth cycle and preventing them from producing seeds.

(Tilling the Soil and Creating Hilled Rows; Cub Cadet Hydraulic Tiller)

Tilling has been challenged in the last half century. Productive soil contains invisible fungal filaments, living threads of mycelium, billions invisible bacteria, and several thousand protozoa. Fungi help plants take in water and nutrients by causing roots to grow larger and deeper. Soil is more than the sum of their parts. Tilling kills living webs of interconnected organisms and destroys underground networks that connects plants. Rototilling cuts and scores fungal hyphae, slices worms in pieces and destroys arthropods and nematodes.

OUR EXPERIENCE: At GroEAT Farm in Montana, we have experimented with tilling for many years and have had great success with this method. Not only has tilling reduced weeds over the years, it appears to make the soil lighter and fluffier. Garlic loves fluffy soil. We've observed that tilling the soil, after adding loads of organic matter, helps make the soil more productive. The tilling mixes and integrate the layers of organic matter and makes planting easier in the fall. Garlic appears to thrive in lighter, fluffier soil. Yes, the soil is tilled in the fall, and the important living webs of interconnected organisms are been disrupted. Our solution? We make and apply a special "Soil Bacteria Food" to feed the bacteria over the next nine months. This helps restore the important living webs of interconnected organisms.

How to Make Soil Bacteria (YouTube):

4. Weeding by Hand

Bending over and weeding regularly (hand weeding) can be an effective way to remove weeds. TIP: Weeding after it rains or after the soil is watered deeply makes weeding easier! The moist soil makes weeding so much more effective! Don't wait too long to weed your garlic. When weeds are small, their roots are weaker, making it easier to pull them out. Grab each weed individually at its base and then pull slowly and steadily to ease the roots from the soil. Snatching a handful of weeds often causes the weed to snap in two, leaving the bottom half and the roots still in the ground. Some stubborn weeds send deep roots that are extremely hard to pull. When dealing with these tough plants, use sharp snippers.

5. Natural Mulch

Mulch, in simple terms is a material that covers the soil’s surface. Mulching is a process of applying these materials to the surface of garden soil to retain soil moisture by preventing water evaporation specially in summer, to keep the soil temperature cooler, and to suppress weed growth. The thickness of mulching can vary depending on the size of the plant. Common mulching materials that can be used include shredded leaves, shredded bark, coconut coir or coconut husk, and straw. Additional mulching materials include wood chips, saw dust, grass clippings, shredded newspaper, cardboard, wool and animal manure. Mulching has sustainable and ecological benefits. Done correctly, mulching feeds soil’s living microorganisms with nutrients, and the waste from these tiny microbes creates healthier soil structure for plants, limiting compaction. Because garlic competes poorly with weeds, mulching garlic leads to bigger and better yields. Mulch not only buffers garlic cloves and new plants from strong winds, mulch provides a physical barrier on the soil surface and when applied property, and blocks nearly all light reaching the soil's surface. If weeds emerge beneath the mulch, they will not have sufficient sunlight to survive.


  • Reduces weed growth by keeping light from reaching the soil surface.

  • Reduces water loss from the soil surface, which helps maintain soil moisture.

  • Moderates soil temperatures, keeping it warmer on cold nights and cooler on hot days.

  • Protects bare soil, reducing erosion and soil compaction.

  • Protects plants from the harsh conditions of winter freezes, thaws, and winds.


  • Too much mulch can bury garlic plants; Garlic plants are resilient and will eventually find their way out of the mulch.

  • Mulch creates a cool, dark hiding place for Slugs, earwigs, cutworms, and other pests. In other words, mulch near plant stems can provide a lovely home for slugs, snails, tunneling rodents, and pests.

  • Heavy rains can make the ground soggy for several days. Mulch can trap moisture. If a garlic patch gets really wet, take off the mulch and let the soil dry.

  • Improperly-composted or fresh animal manures may contain excessively high levels of nitrogen and is harmful to plants. Be sure that any animal manure compost you use has been well-aged. Manure from dogs, cats, humans and pigs should be avoided altogether as they can carry pathogens that are harmful to humans.

  • Decorative colored bark may have been treated with chemical dyes, making it unsuitable for organic edible gardens.

  • Pine bark is more acidic and takes longer to break down than hardwood mulch like cedar, fir or redwood, so is better suited for pathways or around trees than directly in veggie or flower beds.

6. Plastic Mulch

Plastic mulch is a type of inorganic mulch. It is a thin plastic film typically made from polyethylene. This thin film is laid on top of soil and shields soil from the elements. The polyethylene film is usually a sheet of black plastic and it works the same way as organic mulch, the film insulates the soil, prevents soil erosion, and reduces moisture evaporation. Crops such as garlic can be planted through slits or holes in the plastic sheeting. Since plastics are impervious to water, soil water will not evaporate, significantly reducing water loss. Drip irrigation is typically used with plastic mulch. Mechanized equipment can be employed to make the plastic mulch layer applications easier. Plastic mulch film and drip tape can be applied all in one pass.

(Applying Plastic Mulch Film)

Prior to or during harvest of garlic, the plastic mulch film is removed. Disposal of plastic mulch is cited as an environmental problem; however, technologies exist to provide for the recycling of used/disposed plastic mulch into viable plastic resins for re-use in the plastics manufacturing industry.

7. Landscape Fabric

Landscape fabric is constructed from woven fibers and is manufactured as a solid sheet which allow water to soak through. Some brands offer UV protection to maintain the life of the fabric. It can be made from an assortment of materials, including linen, polyester, and recycled plastic. Usually, it’s a woven cloth laid in garden beds to help keep weeds at bay. Is landscape fabric all we need to get rid of those pesky weeds for good?

Here's the bad news. Landscape fabric has a tendency to compact soil. We've noticed that soil underneath the landscape fabric does not stay light, fluffy and crumbly. Rather, the soil becomes harder and more compact as compared to the soil that is not under landscape fabric. While the landscape fabric will reduce the number of weeds under that covered area, that weeds that do have the strength to emerge can become enmeshed into the fabric and can make a mess. Are harmful chemicals from the landscape fabric leaching in to your soil? If the fabric mesh contains petroleum or other chemicals, the answer might be yes. Landscape fabric is also expensive and costly to replace. The long, steel stapes used to hold the fabric down (to prevent it from blowing away) can become easily lost and buried int he soil, and can easily puncture a foot. If holes are made in the fabric to facilitate the planting of seed garlic, the holes may not be large enough to allow the fully-grown garlic head / bulb from being extracted. Therefor, the landscape fabric will need to be removed before harvest, which really can be a difficult and labor-intensive task.

Disadvantages of Landscape Fabric

  • Not flexible: Each time you make a hole in the fabric (for planting), the fabric becomes less effective. So, it's not practical for gardeners who want to rotate planting areas.

  • Not Idea for Wet Conditions: Garlic does not like the have wet feet. If the roots and growing bulbs stay wet for an extended period of time, they can rot and die. Mold and other disease may also flourish in the wet environment under the fabric.

  • No more natural nutrients: Organic mulches, like horse or cow manure leach into the covered soil more slowly, and it takes more time for the nutrients to work their magic. It is also more difficult, if not impossible to mix organic material deeper into the soil.

  • Less effective over time: After a while, soil packed underneath loses breathability, and plant roots can suffer from the compacted soil.

  • Not Perfect: Plant roots in search of air and water can grow through the cloth, breaking the weed barrier.

(Landscape Fabric and Garlic Production)

Here is some good news. Landscape fabric allows garlic growers to "Tarp and Grow" at the same time. It reduces weeds, warms the soil in the spring, helps retain moisture in the soil, allows moisture to enter the soil (unlike plastic film mulching), and creates a protected and cozy environment for worms to thrive. Landscape fabric reduces the amount of space where weeds can germinate and can also be considered a "No Till" operation.

Advantages of Landscape Fabric

  • Helps Prevent weeds: Fabric virtually prevents sunlight from reaching weed seeds, which reduces or eliminates them.

  • Cost-effective: Fabric can last for years, so there's no need to spend time weeding or waste monty on other weed-control methods every season.

  • Environmentally-friendly: This cloth limits the need for harsh weed control chemicals. Plus, some are made from recycled materials.

  • Better than Plastic: Unlike plastic alternatives, landscape fabric has tiny holes that allow water to reach plant roots.

  • Conserves moisture: Adding this reduces surface evaporation, so less watering is needed.

8. Burning Weeds with Flames

Burning weeds with fire (Flaming) can be used to kill or suppress the flush of weeds during the growing season. Flaming is particularly effective on garlic crops that have slow growing rates. Flaming is more effective on small broadleaves than on grass weed species. A propane weed burner, furnishes an intense flame directly to the weeds, scorching and killing them. Plants may wilt, change color, or appear unaffected soon after flaming. Even if no change in the weeds is evident immediately, proper flaming causes plants to yellow and die within several days. A weed burner that connects to a standard propane tank delivers a deadly flame directly to the weeds, scorching and transforming them into black char. A weed burner works well between rows of garlic. Be sure weeds are green; Brown and dry weeds can start a fire. Check with local authorities before using a weed torch. Only an experienced operator with demonstrated skill and good judgment should be allowed to flame weeds. Wet conditions during the rainy season or after a thorough irrigation are often good times to flame. Work when winds are absent and when open flames are visible. Keep fire suppression equipment (e.g., a fire extinguisher, shovel, water) handy in case of an accident.

(Using a Propane-Fueled Flamethrower to Burn Weeds in a Garlic Patch)

IMPORTANT WARNING: SOME PLANTS ARE POISONOUS WHEN BURNED. If poison ivy is burned and the smoke then inhaled, a rash will appear on the lining of the lungs, causing extreme pain and possibly fatal respiratory difficulty. Other plants that can cause life-threatening issues when burned include: Deadly Nightshade, Jimson Weed, Poison Oak, Giant Hogweed, Stinging Nettle, Water Hemlock, Poison Sumac, and Death Camas.

9. Mechanical Weed Control

Mechanical weed control, such as cultivation, is an important strategy for managing weeds in organic systems. In organic row crops, such as garlic, mechanical cultivation is useful for adequate weed control. Mechanical cultivation can also damage delicate root structures of garlic. Mechanical weed control includes the use of preplant tillage such as plowing, disking, and field cultivating. These types of primary and secondary tillage can help reduce the rate and spread of certain perennial weeds and can also kill emerged weed seedlings and bury weed seeds. To control very small weed seedlings that are just beneath the soil surface or barely emerged, implements such as a rotary hoe, chain-link harrow, or tine weeder are dragged over the field. These implements will displace small seedling weeds and expose them to the drying effects of the wind and sun. Garlic may require many cultivations depending on weed species, severity, and rainfall. Cultivation works best when performed during the heat of the day in bright sunlight; weeds die under these conditions. Rainfall shortly after cultivation may allow weeds to recover and survive. Hand-pulling weeds that escape the cultivator will help prevent weed seed production, which can affect future weed problems. Mowing can also play a role in managing weeds in between rows of garlic crops. Repeated mowing reduces weed competitive ability, depletes carbohydrate reserves in the roots, and prevents seed production. Mowing can kill or suppress annual and biennial weeds and may suppress perennials and help restrict their spread. A single mowing will not satisfactorily control most weeds; however, mowing three or four times per year over several years can greatly reduce and occasionally eliminate certain weeds.

10. No-Till Farming

No-till farming is an agricultural technique for growing crops without drastically disturbing the soil through tillage. No-till farming decreases the amount of soil erosion. No-till farmers grow crops with minimal disturbance to their fields and the organisms that call them home. This apparently builds healthier soils while reducing money spent on fuel and labor. No-till garlic farming is a system in which the seed garlic are planted directly into untilled soil which still contains the previous crop residues. No-till cultivation of garlic minimize soil disturbance and allows crop residues or stubble to remain on the ground instead of being removed or dug into the soil. You start by covering the soil with four to six inches of organic mulch (dried leaves, grass clippings, or hardwood chips). The mulch helps keep the soil beneath moist, and also prevents weed seeds from sprouting by keeping light from reaching the surface. When you want to plant seed garlic, just push the mulch aside in that spot. Once you’ve established a no-till garden, add a few inches of mulch every year (the old mulch will biodegrade and settle) and push the soil aside as described each time you plant. This no-till approach prevents and reduces weed seeds from germinating and sprouting.

Using Cardboard. If there are many weeds in the area you wish to plant garlic, begin by mowing the area. Some farmers lay down a layer of cardboard before adding organic matter. They then thoroughly wet the cardboard to help it break down. The cardboard will serve as a further barrier to weeds, exhausting and eventually killing most of them off. Reusing cardboard for a garlic plot provides compostable material, kills pesky weeds and develops a bumper crop of earthworms. As cardboard is a highly recyclable material so almost 70% of the new cardboard is made from recycled paper. Cardboard in the garden will also kill lawn grass and help you get a new bed ready for garlic or whatever you want to grow. CAUTION: Some boxes made from cardboard contain a percentage of mineral oils which is toxic for health. Some older cardboard boxes contain a wealth of chemicals. Just a few years ago, the U.S. Food and Drug Administration moved to ban three chemicals that were traditionally used in a wide variety of popular boxes and packaging such as commonly used pizza boxes.

Here are a few suggestions on how to proceed with No-Till Farming.

  1. Don’t Disturb the Soil. When beneficial fungi are present in healthy soils, tilling has the potential to destroy this delicate web of life. By not disturbing the soil, it can begin to rebuild fungal populations and bring soil biological community back in equilibrium. This method can help nitrogen become available through soil biological activity.

  2. Keep plant biomass and plant residue on the soil surface. This helps protect soils from the impact of raindrops, wind, or intense heat. Keep the Soil Covered.

  3. Provide Soil with Food. Soil organisms don’t have enough food to sustain themselves when crops are in the active stages of growth. Plants such as garlic are heavy feeders and take up many of the sugars and nutrients stored in the soil. Make your own soil food. To increase soil bacterial and feed them as well, mix water, molasses, rice and milk together, and let this smelly concoction sit for two weeks in a warm environment. After this liquid food ferments, dilute and pour directly on the soil.

  4. When garlic has numerous green leaves and the plant is growing, the plants produce sugars that attract and feed soil biology that is beneficial to them.

11. Natural Herbicides

Instead of using chemical herbicides, organic farmers can implement a variety of conservation practices that suppress weeds while building soil health. One of those practices is the use of natural herbicides. This may sound like a oxymoron, but natural herbicides do exist.

When looking for a natural alternative to herbicides, a cocktail of vinegar, dish soap, and salt includes ingredients needed to quickly kill weeds. Acetic acid in the vinegar and the salt are both very good at drawing moisture from weeds. Acetic acid or vinegar is an ingredient in a number of products, but it may not be currently approved as an herbicide for organic crop production systems. Additional products and ingredients are currently under review for use in organic gardening. Potassium salts and fatty acids are effective at killing unwanted weeds and grasses. You’ll be able to see results within hours and this weed killer won’t travel through the soil to kill nearby plants. Corn gluten meal is sold as a preemergence herbicide in some production systems. However, because of the volume of product necessary and the associated cost, corn gluten meal is generally not practical for larger crop production. Commercially available nonsynthetic postemergence herbicides contain plant-based ingredients, including eugenol (clove oil), garlic, and citric acid, and act as nonselective contact-type herbicides. They will injure or kill all vegetation they come in contact with.

Nonsynthetic adjuvants (such as surfactants and wetting agents) can be effective in weed management. The need for the use of herbicides derived from plant or animal sources should be explained in your Organic System Plan, and you must obtain permission from your organic certifying agencies to use these materials. Here is a list of EPA approved organic herbicides: Matratec (50% clove oil) WeedZap (45% clove oil + 45% cinnamon oil) GreenMatch EX (50% lemongrass oil) Avenger Weed Killer (7