Organic Pest Control

Garden Beds

Garden Beds

Organic pest control is now something to think about since Portland gardens are now underway.  Our garden has come a long way since we planted back in March (see our previous post about gardening with recycled materials) and it would be a shame to see all the hard work go to waste.  Let’s start off with our rapidly growing greens.

First, as you can see in the above picture it’s important to start with fresh seeds.  All of our crops with the exception of one quadrant took off, leaving a barren patch where we planted more spinach.  Make sure to buy from a reputable gardening store, avoiding the flashy displays at grocery stores and other discount stores that don’t sell out of seeds yearly.  In our case, we have more produce than we can possibly consume so it’s not a big deal.  However, if you are in an apartment or small space, you want to make sure you put your best foot forward.

Now that the greens are well on their way, it is time to start monitoring for some of the following pests.  Obviously, things will be different based on where you live and the time of year, but below are some common ones to monitor.

Leaf Miners


I have observed this in our backyard crops in the past and simply thought it our plants were burnt during some of our hot days (and forgotten watering schedules).  After some resarch I found these injuries are actually caused by a group of insects generally referred to as leaf miners.  Wikipedia says, “The vast majority of leaf-mining insects are moths (Lepidoptera), sawflies (Symphyta) and flies (Diptera), though beetles and wasps also exhibit this behavior.”  The larva lives in the leaf tissue and eats this until it reaches maturity and starts the cycle again.

Controlling these pests without the use of insecticides can be difficult, but it is not impossible.  Organic Gardening suggests the following methods:

  • Exclude adult flies by using row covers.
  • Encourage parasitic wasps by planting nectar-and pollen-rich flowers with small, shallow blooms, such as dill and yarrow.
  • Cultivate the soil in fall to disturb pupae.
  • Control weeds such as lamb’s-quarter and dock that are known to be leaf miner hosts.
  • Rotate spinach, chard, and beet crops.
  • Use a neem-based spray in severe cases. Neem acts as a repellant and also slows the leaf miners’ ability to feed, interrupting the cycle.

Companion planting is another method of organic pest control.  Think of this as planting a treat so much more tasty than spinach that the insects are distracted and drawn to that plant instead.  Some of these plants include lambsquarter, columbine, and velvetleaf.


The amazing aphid

The amazing aphid

We’ve written about this in the past (see our article, “Organic ways to get rid of aphids in your vegetable garden” for details) so we won’t spend much time on this here. I will note, however, that you need to get these guys under control as soon as you notice them.  I have some fledgling hops growing and I’m keeping an eye on them because as Freshops notes, “… mother aphids carry embryos that are carrying their own embryos. This telescoping reproduction strategy results in quick population growth.”  From a Darwinian perspective this is an amazing evolutionary tactic but from the perspective of someone that wants to supplement groceries with great home-grown produce, this is pretty annoying.

Slugs and snails

We featured an article last year on controlling slugs , which also happens to work on snails, too (see Organic ways for how to get rid of slugs in your garden).  There are also other ways to deal with these pests and they range from putting a dish of beer out by your plants to waiting until dark and then stalking them one by one to try to cull down the population.  Try out some of the more creative methods listed at Weekend Gardener just this last month.  Many of the solutions are a bit odd, if not highly entertaining.

Squash Bugs

We misidentified these as harmless box elder bugs when in fact, these little guys were tearing up our squash.  Lesson learned.  Here’s a comparison of the two bugs in case you are confused, too:

Squash bug

Squash bug

Box elder bug

Box elder bug

Controlling these pests (the squash bugs, not the box elders) requires careful monitoring of your plants.  Look for egg clusters underneath your leaves.  Feel free to scrape them off.  If they become too numerous and you see them crawling all over your vegetables, pull them off.  One person at Mother Earth News said using a shop vacuum to remove these pests en masse is also effective – and somewhat satisfying.


In my experience, caterpillars are the most destructive of the group.  While aphids and others will swarm in the tens of thousands and cause damage, just a handful of caterpillars eating their weight day in and day out can quickly turn a bountiful garden into rows of mangled leaves.

They range in size, color, and shape, but for the most part strategies for control are basically the same for all species.  Organic control includes:

Hand picking as you see them

Attract birds to your garden with bird baths and bird houses – they eat them up like candy

Encourage caterpillar predators to take up residence in your yard through building basic insect houses.  Green Harvest notes:

Insect predators of caterpillars include: assassin bugs; tachinid flies; paper wasps, which chew up caterpillars and feed them to their larvae; lacewings and ladybirds eat moth eggs; tiny trichogramma wasps parasitise moth eggs; other tiny wasps like Apanteles sp. parasitise the caterpillar, the wasp larvae feed on non-essential parts of the caterpillar. When the wasp larvae are ready to pupate their exit generally finishes off the host caterpillar. Sounds gruesome but it is a part of nature.

They also have a number of other tips on controlling these pests, so hop over and check them out when you have a chance.

The Result

Fresh Spring Salads

Fresh Spring Salads

The results are seriously worth it.  If you stick with it and keep an eye on things, your organic garden will take care of you, too.  As noted in our article on block gardening (also known as square foot gardening) back in the fall, a small 2-foot by 2-foot garden that’s kept up can provide a daily salad.  The greens also taste much better than anything you can buy at your local high-end organic supermarket.  Add to that the satisfaction of growing it yourself and you’ve got a pretty satisfying dinner.

If you have any bug problems or suggestions on how to organically control garden pests, please share them in the comments.

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