Treating plants with plants: Natural, Organic Remedies for the Garden

Mortar and pestleAs a health practitioner, homesteader, and lifelong student of ecology, I have witnessed the highly detrimental toxic effects of pesticides, fungicides, herbicides, and insecticides on the health of living and non-living beings, including of course our own health. By non-living beings, I mean water, sky, and non-living components of earth (i.e. absorbent minerals). Take, for example, the use of the world’s most popular non-biodegradable herbicide, Roundup. In some areas, it has contaminated the water table to the extent that an analysis of its active ingredient, glyphosate, now shows up on people’s water bills. It is also found in many common foods we eat (two researchers who recently published a peer-reviewed report on Roundup discuss food contamination and its implications here).

Glyphosate has been linked to gastrointestinal disorders, diabetes, heart disease, obesity, reproductive issues, cancer, Parkinson’s disease and Alzheimer’s disease (see the following article: Another comprehensive study conducted by Harvard researchers showed that pesticide and herbicide exposure increase the risk of developing Parkinson’s disease by 70%. Dr. Ascherio, who led the research, warns, “We also found this relationship in people who were … not occupationally exposed to the chemicals. This suggests that even low levels of exposure—just spraying in the backyard, for instance—could be important.” This corresponds with the experience of many health practitioners. We are seeing many patients falling ill with a number of diseases shown to be related to chemical contamination. There is much I could say on this subject…

Conventionally grown apple trees are among the fruits with the highest amount of toxic pesticides.

Conventionally grown produce contains high levels of pesticides.

In brief, it breaks my heart to see the harmful effects that gardeners and farmers can have on the environment and its inhabitants by resorting to chemical warfare on weeds, insects and diseases affecting crops. And I imagine that if you find yourself reading this post, it concerns you deeply as well. As an increasing number of us now know, finding natural and healthy alternatives to toxic sprays is so essential for the preservation of health – both our own health and that of all the creatures and elements on which everyone’s wellness depends. Therefore, I’ve begun compiling some of my favourite organic remedies for the garden. Feel free to share them with your neighbours, family, and friends. Join the ongoing movement to clean up our world, beginning with our own neighbourhoods and fields!

First: Spraying Basics for Natural Remedies

  1. It is best to use any type of spray in the early morning or the cool of evening. Do not spray when temps are above 26ºC or 80ºF. Your plants may “burn” or have a reaction (even with natural remedies) if treated during excessive heat (plain water can also have this effect, as those who’ve tried watering plants at midday will know).
  2. Always perform a test on a small portion of the plant material first. Wait 24 hours to observe any negative reaction. Proceed if there is no damage.
  3. Really and truly…more is not better. If you are not getting good results don’t increase the strength of these remedies without testing first.
  4. Target just the area you need to treat. Be careful not to harm beneficial insects. You don’t want deter your allies from showing up where you need them most.
  5. When working with sprays or dusts always protect your face and exposed skin. Some of these ingredients can be irritating to your skin, eyes and mucous membranes, especially any hot pepper sprays.
Remedy Problem
Baking Soda Spray Anthracnose, early tomato blight, leaf blight and spots, powdery mildew  & as a general fungicide for common mildews on cucumber, asters, tomato, squash and zinnia foliage.  Also for mosaic disease control on cucumber, lettuce & tomato
Chive Spray Prevention of apple scab and powdery mildew on cucumber, pumpkin and zucchini
Compost & Manure Teas Blights & general disease
Corn & Garlic Spray General fungus preventative
Elder Leaf Spray Black spot & mildew
Garlic Fungicide Spray #1 Mildews & leaf spot
Garlic Fungicide Spray #2 Fungicide and insect repellent
Horseradish Spray Brown rot in apples & general disease prevention
Hydrogen Peroxide Treatment General disease preventative and direct treatment
Apple Cider Vinegar Fungicide  Leaf spot, mildew & scab


Specific Disease Controls

Apple tree scab: Grow any member of the onion family around the base of the tree. Chives work the best. You can also make a tea from chives and use as a spray on your apple trees to help protect from scab.

Brassicas: Keeping the soil pH around 7.0 to prevent club root disease.

Peach tree leaf curl: This is a common disease of peach trees. Sprays of horsetail tea, garlic (look further down the page for recipes) and seaweed can help to prevent this problem. Growing chives underneath them also helps. For best results use a mix of fermented horsetail, nettle, and comfrey tea as prevention.

Neem Oil: This medicinal oil will help prevent rust disease, black spot and can act as a general fungicide.

Potato scab: When planting your potato sets put some wilted comfrey leaves in with them to prevent scab. Keeping the soil for your potato patch to a pH of 5 or below (acid) or a pH of 7 or above (alkaline) prevents scab.

General Disease Controls

Apple Cider Vinegar Fungicide: for leaf spot, mildew, and scab

  • Mix 3 tablespoons of organic apple cider vinegar (5% acidity) with one gallon (3.8 litres) water and spray in the morning on plants. Good for black spot on roses and aspen trees, too.

Baking Soda Spray: natural, non-toxic antifungal spray


One of our zucchini plants with that classic powdery mildew look towards the end of season. Simply spray the plants with baking soda and the leaves magically return to perfect health.

Uses: Anthracnose, early tomato blight, leaf blight and spots, powdery mildew and as a general fungicide.

Sodium bicarbonate, commonly known as baking soda, has been found to possess fungicidal properties. For plants that already have powdery mildew, hosing down all the infected leaves prior to treatment is recommended. This helps to dislodge as many of the spores as possibly to help you get better results. Use as a prevention or as treatment at the first signs of any of the diseases.

To make: Mix 1 tablespoon baking soda, 2 1/2 tablespoons organic vegetable oil with one gallon (3.8 litres) of water. Optional: add 3 – 5 drops of essential oil of tea tree or lavender. Shake this up very thoroughly. To this mix add 1/2 teaspoon of pure Castile soap or ecological dish soap and spray. Be sure to agitate your sprayer while you work to keep the ingredients from separating. Cover upper and lower leaf surfaces and spray some on the soil. Repeat every 5-7 days as needed.

To Control Powdery Mildew:  Use resistant varieties whenever possible.

 Once the disease becomes a problem:

  • Remember to use ecological dish soap (we only use 1/2 teaspoon of eco soap) and aluminum-free baking soda (i.e. Bob's Red Mill brand for my friends in Canada/USA)!

    Remember to use eco dish soap (we only use 1/2 teaspoon) and aluminum-free baking soda

    Avoid late-summer applications of compost (or any nitrogen-rich fertilizer) to limit the production of succulent tissue (which is more susceptible to infection).

  • Avoid overhead watering to help reduce the relative humidity or water in the early morning to let the tissues dry as soon as possible.
  • Remove and destroy all infected plant parts (leaves, etc.). For infected vegetables and other annuals, remove as much of the plant and its debris in the fall. This decreases the ability of the fungus to survive the winter. Do not compost infected plant debris. Temperatures often are not hot enough to kill the fungus.
  • Selectively prune overcrowded plant material to help increase air circulation. This helps reduce relative humidity and infection.
  • Researchers at the University of Rhode Island have confirmed that the baking soda recipe above is also effective against powdery mildew on roses. It works brilliantly for my winter squash, zucchini and cucumber plants.

Chive Spray: for preventing apple scab and powdery mildew on cucumber, pumpkin and zucchini.

To make: Put a bunch of chopped chives in a heatproof glass container, cover with boiling water. Let this sit until cool, strain and spray as often as two to three times a week.

Compost and Manure Teas

Many people have used manure tea successfully to  keep blight and other pathogens away from plant. Soak the area around plants and use as a foliar spray. Do not use on seedlings as it may encourage damping-off disease.

Fill a 30 gallon (115 litre) trash can with water. Let sit for 24 hours to evaporate the additives (use rain water if you can). Add about 4 shovels worth of manure to this and cover. Let it sit for  2-3 weeks, stirring once a day. Strain and apply as needed.

Manure Tea - that good sh!t

Manure tea – that is good sh!t

Various manures supply nutrients as follows:

  • Chicken manure: nitrogen rich: use for heavy feeders such as corn, tomatoes and squash.
  • Cow Manure: potash: use for root crops.
  • Rabbit manure: promotes strong leaves and stems.
  • Horse manure: leaf development.

Compost Tea: Make and use just the same as you would the manure tea. This is another terrific reason to compost all those prunings, grass clippings and kitchen waste.

Corn and Garlic Spray: Fungus Preventative

This blend is surprisingly potent preventative spray to protect your plants.

  • To make: gather a handful of corn leaves, clematis leaves (any kind) and as much of the papery outer leaves of garlic as you can. Process thoroughly in a blender. Then mix with sufficient water to make a thin liquid. Let sit for an hour, strain and spray on plants as a preventative.

Couch Grass Rhizome Tea: for preventing mildew and fungus disease

  • To make: put a handful of fresh rhizomes in a glass pot. Pour 1 quart (1 litre) of boiling water over rhizomes, cover and let steep for 10 minutes. Strain, let cool and use right away.

Elder Leaf Spray: Elder leaves have fungicidal properties and may be useful against mildew and black spot diseases.

  • To make: simmer 8 oz (240 ml) of leaves in 16 oz (480 ml) of water for 30 minutes. Stir this thoroughly, then strain. Take 16 ounces of warm water and mix with 1 tablespoon of Castile soap. Add soap mixture to the elder water, spray as needed. Note: Set your sprayer to a coarse or large droplet setting as this mixture will tend to plug a fine setting.


Garlic Fungicide Spray #1: For leaf spot and mildews

Garlic is a great natural and non-toxic fungicide.

Garlic is a great natural and non-toxic fungicide.

  • To make: Combine 3 oz (90 ml) of minced garlic cloves with 1 oz (30 ml) of mineral oil. Let soak for 24 hours or longer. Strain.
  • Next mix 1 teaspoon of fish emulsion with 16 ounces of water. Add 1 tablespoon of castile soap to this.
  • Now slowly combine the fish emulsion water with the garlic oil. Kept in a sealed glass container this mixture will stay viable for several months. To use: mix 2 tablespoons of garlic oil with 1 pint (500 ml) of water and spray.

Garlic Fungicide Spray #2: Fungicide and Insect repellent

Put in a blender: 1 whole head of garlic, 3 cups water, 2 Tbs canola oil, 4 hot peppers and a whole lemon. Blend until finely chopped. Steep mixture overnight. Strain through fine cheesecloth. Use at a rate of 4 Tbs per gallon (3.8 Litres) of water. Store unused portion in the refrigerator.

Horseradish: preventative for fungal disease

Penn State University announced in 1995 that minced horseradish holds promise in decontaminating wastewater and now says it may clean contaminated soils as well!
Penn State’s centre for Bioremediation and Detoxification reports that minced horseradish combined with hydrogen peroxide can completely remove chlorinated phenols and other contaminants found in industrial wastes. Experiments involve applying the mixture directly to tainted soils or growing horseradish in contaminated soil and roto-tilling the roots just before applying hydrogen peroxide!

The cleansing properties of horseradish have been known for more than a decade, however creating a purified form has been far too expensive. This method has proved to be just as effective, but at a fraction of the cost!

Horseradish Tea: You can also make a tea from horseradish roots to use as a preventative spray for fungal diseases. This is especially useful against brown rot in apple trees. The white flesh of the horseradish root also contains significant amounts of calcium, magnesium and vitamin C.
To make: Process one cup of roots in food processor till finely chopped. Combine this with 16 ounces of water in a glass container and let soak for 24 hours. Strain liquid, discard the solids. Now mix the liquid with 2 quarts of water and spray.

Hydrogen Peroxide Treatment

To prevent bacterial and fungal problems on outdoor plants use hydrogen peroxide! Hydrogen peroxide will prevent the disease spores from adhering to the plant tissue. It causes no harm to plants or soil, however don’t use on young transplants or direct seeded crops until they have become established. Warning: Always test on a small portion of plant tissue first to check for any negative reactions. Do not proceed if there is any damage to plant tissue. Do not substitute food grade H2O2 for the common H2O2. Spray plants with undiluted 3 percent hydrogen peroxide that you can buy most anywhere. Be sure to cover tops and bottoms of leaves. Do this once a week during dry weather and twice a week in wet weather. This works as a preventative. If you already have problems use this as a direct treatment.


Save your eggshells for starting your seeds!

Save your eggshells for starting your seeds!

Seedlings: Damping off disease

Always use a sterile growing medium like mixes with vermiculite and perlite for your seed starting as these should not contain the fungi that cause damping-off. Water your seedlings with warm water that has been left to sit for an hour or more to dissipate most of the chemicals that are present in tap water. Using cold water stresses the seedlings leaving them vulnerable to harmful organisms.

    1. Chamomile Spray: Chamomile tea is an excellent preventative for damping-off. Use on seed starting soil, seedlings and in any humid planting area. Chamomile is a concentrated source of calcium, potash and sulphur. The sulphur is a fungus fighter. This can also be used as a seed soak prior to planting.

      INSTRUCTIONS: Pour 2 cups boiling water over 1/4 cup chamomile blossoms. Let steep until cool and strain into a spray bottle. Use as needed. This keeps for about a week before going rancid. Spray to prevent damping off and anytime you see any fuzzy white growth on the soil. Chamomile blossoms can be purchased at health food stores and usually grocery stores.

    2. Seaweed Spray: A seaweed spray which is so rich in nutrients and everything that seedlings require can also be used to prevent damp-off. Make a strong mixture adding 2/3 cup of kelp concentrate to 1 gallon (3.8 Litres) of water, spray. (Careful where you source your seaweed; many seaweeds are now contaminated by heavy metals).
    3. Horsetail Tea (Equisetum arvense): The common horsetail plant, which is very invasive, is rich in silicon and helps plants to resist fungal diseases via increasing their light absorbing capabilities. Use on peach trees to control peach leaf curl. Use on most plants to combat powdery fungi, and on vegetables and roses to control mildew. You can use this on seedlings and plants in closed environments too! Great in greenhouses! Prevents damping off.

      INSTRUCTIONS: In a glass or stainless steel pot, mix 1/8 cup of dried leaves in 1 gallon (3.8 Litres) of non-chlorinated water. Bring to a boil, then let simmer for at least 1/2 hr. Cool and strain. Store extra concentrate in a glass container. Will keep for a month. Dilute this mix, adding 5-10 parts of non-chlorinated water to one part concentrate. Spray plants that show any symptoms of fungal type disease once every 4 days. Spray your seed starting mixtures to prevent damping off.

    4. CinnamonThe best damping off remedy: Powdered cinnamon!
      Sprinkle powdered cinnamon on the soil-free medium surface. Don’t worry if you get cinnamon on your plants as it will not hurt the tender seedlings. We have been using this method for years with near 100% effectiveness.


When we use natural remedies to care for our plants, we do so with the peace of mind that can only come from using non-toxic ingredients easily sourced from home or our local organic market. We are contributing to the protection of interconnected ecoystems (which includes us!) rather than to their deterioration.

Let us know if you have any questions or suggestions concerning natural remedies for the garden. We’ll continue to update this post as we try new things that work!