DIY Aquaponics: 5 Best Organic Pest Controls for your Garden

As I was poking around in the garden today, I noticed the first signs of aphids in the okra!

aphids in the okra plant

Unfortunately, pests are an inevitable problem facing ALL gardeners and farmers at one point or another. Combating pesky bugs has always presented an extra difficult dilemma for aquaponic growers. There are so few pesticides that are known to be non-toxic or safe for fish. But when dealing with closed-looped systems — especially when those systems are enclosed in a greenhouse, you will soon find yourself with an out-of-control infestation UNLESS you have a reliable system of pest control in place — made up of your unique combination of methods listed as our 5 favorite all organic pest controls below.

People commonly ask whether “organic” pesticides are always safe. The answer is clearly, NO. Think of the poison, ricin, which is technically natural as it is grown from the castor plant (Ricinus communis). As Bill Doboer explains elsewhere, we avoid using “organic” because it is simply a misunderstood and misused word. In aquaponics (as should be the case in all gardening and farming), the question is not whether a substance is organic, it’s whether it’s toxic to humans or fish. See our post on fish and human friendly fertilization methods, too!

Below is a list of our favorite uber-organic methods of combating and preventing future pest infestations (in ways that will not harm your fish, you, or the environment).

5 Killer (Yet Fish-Friendly) Organic Pesticides

1) Beneficial Insects

This form of “bio-control” consists of adding and raising populations of beneficial insects (lady bugs, aphidius wasps, etc) to feed on bugs that eat your plants. organic method to control aphids using waspsYou can purchase packets of Beneficial Nematodes, tiny microscopic organisms which are effective in killing over 230 bugs (but completely safe for people, pets, and the environment). You can purchase 1,500 live lady bugs online for under $10. Lady bugs will devour up to 50 aphids, mealy bugs, scale, leaf hoppers, or other destructive pests per day! You YOURSELF can even serve as a surprisingly effective live “biocontrol” with a high powered spray bottle or hose and a wet cloth!

If you have just a few pests, putting such beneficial organisms to work in your system will help prevent many pest outbreaks and big infestations.

2) Biological Sprays

Another type of “biocontrol” (as in not synthetically-produced) method for dealing with more stubborn bug populations involves making homemade remedies or buying commercial pesticide sprays made out of organic plant materials or animal byproducts. Examples include garlic/pepper/onion sprays, worm casting tea, fungi spore sprays, and my personal favorite — sweet orange essential oil (just mix a few drops of this in a milk jug filled with water and a teaspoon of dish soap found under #3 — this concoction will handle about any pest infestation you find in your garden!).

If you prefer a commercial spray version, orange essential oil is the only active ingredient in the time-tested pest control product, Orange Guard Home Spray.

DIY homemade organic pesticides

The two methods of pest control (aka “biocontrols“) are all that most backyard gardeners usually need to combat pests and prevent infestations of many pesky bugs. But if you already have a large pest infestation, however, any amount of beneficial bugs or worm poop would prove useless in combating any fast-growing insect population effectively and lastingly. In such cases, you must temporarily incorporate a few of the synthetic chemical compounds listed below in your pest control regimen.

Tips on Using Synthetic Chemical Pesticides 

We recommend implementing a system that incorporates several of the biocontrols described above, but also keeping on hand the chemical pesticides listed as # 3 – 5 below for use at the first sign of infestation. But have caution when doing so!

    • Protect Fish. Using sparingly, and in no circumstances should you allow more than the lethal dosage for fish to rain into your pond! Arrange your system so that the pond is not directly below the grow bed to prevent most toxic runoff and/or use an empty reservoir and flush the system of toxins after each pesticide application. 
    • Protect Beneficial Insects. Only apply at dusk or right after the sun goes down and most flowers close. Open flowers left on the plant may catch the substance and later poison beneficial insects like bees! To avoid this unintended result, pull off any open flowers before spraying (and use to decorate and perfume your house and car!). 
    • Protect Yourself. Wear a mask, eyewear, gloves, pants, long sleeves or even a protective outfit to keep synthetic substances off your skin and clothes and outside your respiratory system. 
    • Prevent Resistance. Rotate using different types of pesticides (biocontrol and synthetic, alike) to avoid resistance build-up in pests
    • Protect Plants. For your crops, the best line of defense is maintaining a strong root and plant structure from the outset. If you keep up the health and vitality of your plants, it will be easier for your system to ward off a pest attack on its own and to recover from any attempted takedowns it may have experienced. Refer to our post on our Fav Fish-Friendly Fertilizers for more info.

3) Soap Sprays

Used in moderation, diluted glycerin based soaps applied to plant foliage are the least toxic “synthetic chemical” substance you can use to control pests in your aquaponic garden. NOTE: be extra careful not to let large quantities of soap getting into your fish tank. Soap is dangerous to fish in significant quantities. Fill a spray bottle with a few drops of glycerin-based soap and spray onto infested area of the plant foliage (careful not to spray or let a ton drip into the media bed itself). Or purchase a pre-made soap spray that comes perfectly diluted for your organic gardening needs like:

Indoor Pharm Organic InsectideIndoor Pharm Organic Insecticide and Fungicide, With Pure Rosemary and Almond Oil — 2 Pack of 33.8 fl. ounce spray bottles ($25.00) on Amazon

  • Made with certified organic glycerin-based soap, almond oil, and rosemary oils
  • Controls insects and prevents fungal spores from traveling and maturing to disease
  • Will prevent powdery mildew
  • Indoor Pharm is safe for use on herbs and edibles
  • Controls fungus gnats, aphids, spider mites, whiteflies and scale

Again, take note that excessive soap scum can clog fish gills and potentially kill your fish. So like everything else on this list — moderation is key! If a few sprays of soap does not keep the pesky creatures at bay, you may need to pursue smaller doses of more toxic alternatives…

4) Neem Oil Spray

Neem Oil Sprays are handy for use as an “on-the-spot” treatment for when you see a few pests or to combat small infestations.

neem oil organic pesticide spray

This Ready-to-Use Neem Oil Spray Product is an all purpose insecticide, miticide, and fungicide for organic gardening. Neem oil can be used on virtually any plant, including roses, flowers, vegetables, herbs, spices, houseplants, trees, turf, and shrubs. Kills all stages of insects, eggs, larvae, and adults. Makes a great dormant spray. Imparts healthy shine to leaf surfaces.

Although product is labeled “organic” — it is harmful to bees and is not the safest thing for your fish — so again I REPEAT use caution: spray small amounts only on plant foliage and away from fish tank (if possible), only AT NIGHT when flowers close up!

Here’s how I made this homemade organic spray using a combination of neem oil, other essential oils, and castile soap. Works good on bugs and a range of diseases. I spray this on my tomatoes, peppers, and eggplants every other week.

5) AzaMax

AzaMax Antifeedant and Insect Growth Regulator (buy 1-Quart of AzaMax for $88 on Amazon) is a natural product with a broad spectrum of pest control.


AzaMax contains Azadirachtin A and B as active ingredients and uses only food grade formulation ingredients — no hard chemical solvents. Works by starving and disrupting the growth of insects (making them weaker and easier to kill). Effective on spider mites, thrips, fungus gnats, aphids, whiteflies, leaf miners, worms, beetles, leafhoppers, scales, mealy bugs, nematodes and other soil borne pests.

Do not use more than you need and ***IMPORTANT*** try to prevent AzaMax from dripping into your grow beds by spreading plastic bags or sheets under plants until fully dry. Mix one tablespoon to one gallon of water. OMRI (“Organic Materials Review Institute“) listed.

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Urban American Gothic Farmers
Urban American Gothic Farmers by Brandon Martella

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