Pesticides are defined as substances that are created or organisms that are used to control pests. 

These can be chemicals, bacteria, fungi, and certain plants and/or animals used in a way to control or prevent crop damage.

Studies show that homeowners use 3 times the amount of pesticides that farmers do each year, impacting local wildlife and contaminating surface water.

Chemical pesticides:

  • Can cause harm to more than your target pest species, including your pests’ natural predators.
  • Because they are man-made, nature can’t always break them down, so they accumulate in the food chain and magnify in strength up the food chain causing detrimental effects to consumer species. Remember the trophic pyramid in Lesson 1? The higher the trophic level, the more food animals have to consume to survive. You can see how synthetic pesticides can accumulate through the food chain here.
  • Pest species develop a tolerance to pesticides over time, just like humans do with antibiotics.
  • They provide short-term benefits with long-term consequences.

Don’t worry, it’s not all doom and gloom. No one has to suffer in this situation. There are many solutions to your pest problem right here!

The first one is…


The best way to protect your garden from pests is to prevent them from visiting in the first place.

A healthy garden requires rich soil with native plants suited to the environmental conditions of your location. This will reduce the chance of pathogens infecting the plant through their roots, and a healthy plant can naturally defend itself from pests and the elements.

Here’s how:

  • Remove plants that are dying, as decomposition can attract pests.
  • Healthy, aerated soils have lots of organic matter, which will attract soil-dwelling insects like worms and beetles that churn and aerate the soil as they move through it. This action produces healthy plants, reducing the chances of them decomposing. 
  • Digging and tilling allows for pests to find their way into the soil and impacts important plant microorganisms. Healthy soils will contain all the necessary insects to keep your plants healthy. (Please see “How to create a no till garden step-by-step” at the end of this page.)
  • Use seaweed (in a mulch or spray) to support healthy plant development and protect your plants from slugs.
  • Use clean mulch to protect your garden soil, keeping it cool and moist, because most root activity occurs close to the soil surface. Straw, spoiled hay, grass clippings, bark mulch, wood shavings, and leaves are perfect.
  • Keep ground foliage dry to prevent pests and fungal damage to roots.
  • Tools used to remove infestations should be disinfected before use again.


Most insects have highly sensitive olfactory senses, meaning they are influenced by their sense of smell to find food, attract a mate, and, in some cases, protect them from predators that would usually attack them.

By planting certain herbs and vegetables together in your garden, you can deter pests from gorging on your gorgeous garden plants, without having to use chemicals.

You can also use many of these herbs to cook with, make teas from, or dry out to make potpourri to keep your house and clothes smelling fresh and clean. 


If you’d like to to learn more about natural garden pest control recipes, visit

All garden pests have predators because they are primary consumers. By planting certain flowering species you can attract these predators to your garden, and reduce the damage caused by pest species. This is by far the best way to control garden pests. By utilizing the natural order of the food chain, nutrients and energy pass through more consumers, supporting more life and storing carbon, before it is returned to the soil to be re-used by plants.

Let’s find out who these beneficial insects are and how we can attract them.

Wasps are attracted by the flower of carrot, celery, parsley, and caraway plants. They will protect your garden from leaf-eating caterpillars.


Ladybugs love flowers from the daisy, tansy, or yarrow family and prey on aphids, mites, whiteflies, and scale.​


Lacewing and hoverflies are attracted to yarrow, goldenrod, black-eyed susan, and aster. They eat aphids, mealybugs, whiteflies, spider mites, moth eggs, scale, and thrips.​

Praying mantises are attracted to cosmos, marigold, and dill flowering plants. They are ferocious predators and prey on many pests like aphids, leafhoppers, mosquitoes, and caterpillars when small. Adults tackle larger insects like beetles, grasshoppers, and crickets.

Nematodes (no photo) are soil-dwelling parasites that feed on pests like cutworms, root weevil larvae, and certain beetles that destroy plant roots and new sprouts before they can establish themselves in the soil. You can buy them online or at garden centers. Unless they are already in the soil, you can’t really attract them using flowers.


These homemade remedies are cost-effective and made from ingredients found around the home. Do not apply to plants on hot, sunny days. Wait for cooler evening temperatures to apply to plants. Otherwise you risk burning and damaging the plant.

Treatment for soft bodied garden pests (slugs, snails)
Many people use salt to kill slugs and other soft-bodied pests, but it’s destructive to the soil and pretty cruel to the animal, especially as it is in its natural environment. So here is another alternative to protect your garden.

Crushed egg shells
An alternative and more organic way to protect your plants is to use egg shells. Rather than throw out your shells, dry them out in the oven; you can do this while you’re cooking to make them brittle. Crush them and sprinkle them around your plants. Any soft-bodied pests will not like the experience. You only need to re-apply when the shells have broken down, providing a second benefit by adding calcium to your soil.

Treatment for plants already under attack
These recipes are natural pesticides and will kill off all insects they come in contact with, both pest and beneficial ones. These recipes are a final resort for pest infestations in your garden, so please use them as such.

Garlic soap spray
1 whole garlic head peeled
1 tbsp dish soap (not containing bleach)
2 tbsp vegetable oil
2 cup water

Peel garlic cloves and blend with oil and water. Leave overnight to infuse. 
Strain out the garlic, add the soap, give it a good shake to blend the ingredients, then pour into a spray bottle and apply on infested plants.

Chili pepper spray
½ cup chopped hot chilis
2 cups water
2 tbsp dish soap (not containing bleach)

Blend the water and peppers together, and leave to infuse overnight. Wear gloves when you strain out the peppers, as contact on skin can cause irritation. Add in the dish soap and pour into a spray bottle. Give the bottle a good shake to bend all ingredients and apply to infest plants.

Treatment for plants with fungal infections
Fungal infections are caused by contact with infected soil or infected seeds. Some pests, like aphids, secrete a sticky substance when they feed on your plant. This can also lead to fungal infections on your plant. 
Bicarbonate of soda has the ability to disrupt fungal cells, causing them to dry up.

2 tbsp Bicarbonate of soda
1 gallon water

Mix the two ingredients until combined. Warm water will help blend the ingredients. Then pour into a spray bottle. Spray your infected plant once a day until the problem stops. 


Tilling your garden can be a long and arduous process, especially when you do it each year. Sadly, this common practice has negative impacts on the beneficial microbes that live in your soil, and we know how important they are, from what we learned in What is Nature: Lesson 1, How Nature Works.

Here, I am going to show you how to set up your garden to let nature do all the hard work for you, while giving you healthy and delicious garden produce each year. These step-by-step instructions begin with a completely empty flower bed or vegetable patch, but you can jump in at Step 5 if you already have plants established.

Step 1
Apply a thick layer (2 in/5 cm) of compost or manure on top of your bare soil. Make sure it is evenly spread out. This is a huge boost of nutrients and energy for your newly planted flowers, fruits, or veggies.

Step 2
Decide where you will be putting your plants in this patch. Hole size and depth will vary depending on what you are planting. So do a little research on your chosen plants if you’re not sure what their requirements are.

Step 3
To protect your garden from invasive weeds, apply a layer of natural mulch: wood chippings, straw, fallen leaves, or pine needles. This will block the sun from helping weeds to grow if they establish. It also makes weeds easier to see and pull if some manage to make it through.  

Step 4
When the fruits of your labor have finished for the year and harvest is complete, instead of pulling out your plants, cut all stems down to the lowest point. Compost the trimmings and let the roots break down in the soil over winter. 

Step 5
Now we have made it to the following year. Repeat the process in Step 1, spreading a 2 in/5 cm layer of compost across your garden patch. Do not use manure this time.

Step 6
Ready to plant your crops again, rotate your plants and put them in different places. This will bind and enrich the soil at different depths and with different nutrients because each plant has different needs. Only remove last year’s plant remnants if they get in the way of where you want to place your new ones.

The following years
We have completed the steps for the first 2 years to establish the base of your no-till garden. Step 4, 5, and 6 are the only steps you need to follow each year now.

Year 3 – replace compost in Step 5 with mulch
Year 4 – replace compost in Step 5 with soil 
Year 5 – replace compost in Step 5 with rotted manure
Year 6 – replace compost in Step 5 with compost

Repeat this cycle again when you start year 7.


Copyright © New England Primate Conservancy 2021. You may freely use, copy and share these Learning Activities for educational purposes. 
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