How to Attract Beneficial Insects to Your Garden: Lesson 4 – Compost, patience and thresholds

If you’ve read along with my previous three posts on attracting Beneficial Insects and Mites, I thank you. And I think you’re prepared for something a little more academic, regarding Economic and Cosmetic Thresholds as well as tolerance and patience. 

Really, it takes little to attract good bugs. A healthy garden is all.

But first, we left off with the concept of a No-till garden. The real benefit of that practice is the abundance of life facilitated by actively composting (which is done in-ground with a no-till garden.) But I have more to say on composting, so we start here:

Composting:

Unless you’re a beginner gardener, you likely don’t need me describing composting or the immediate benefits of soil nutrients in your garden. So I won’t. But I will explain why it benefits the bugs. 

Check out this picture. This was a corn stalk, late in the year. As I peeled this back there were thousands of aphids (mostly dead) but a couple of Aphidoletes aphidimyza larva and a big healthy hoverfly larva. It was late in the year to see both of these predators, so they had likely chosen that spot to over-winter as pupa. Notice they fed enough to do so, but will overwinter with an aphid colony to help support their next generation. 

Corn stalks are tough, and my shredder/chipper can’t handle them so I was going to burn these. After seeing this, I established a multi-tier composting system:

Tough, woody bits like corn stalks, tomato stems, actual twigs and weeds go in one bin. Because the weeds are pulled out by the roots and with some soil attached this addition helps provide the necessary fungi and bacteria that will more quickly break down the tougher materials. But it won’t happen quick enough to kill off the aphids or their predators trying to sleep. So, all year I develop this wood and weed bin, and it’ll be left a whole year after it’s finished in the fall to allow weeds to germinate and die, and for beneficial insects (and their food) to leave the pile.

This 18′ corn didn’t break down quick. I cut their stems and left the roots. It took a whole other season for the rest of the stem to loosen from the roots. I simply planted the next crop around it.

The other tier is the quick-return. Twice a year a bin is filled with grass clippings, straw and all the leafy-green, easy-to-digest garden bits (that aren’t weeds). This is your normal compost. Add dry leaves or straw to contribute the carbon that’ll prevent it from smelling and keep it moist and aerated by watering and tossing it. One study I found showed that available nitrogen peeked in a compost pile and was best used at 4 to 6 months. Because I spend 6 months filling it, some bits are only a few weeks old, so I don’t use it that quickly, but I’ll let you all experiment how you wish. 

I also use a vermicompost (worm bin). I did this because we lived in an apartment, and because we liked to cook from scratch and enjoyed veggie markets, we had lots of “kitchen waste.” If you fill a garbage bag with it, it’s a big chore carrying that down flights of stairs every day. So we went about the worm compost. It is fantastic! What my wife and I produced (of uncooked fruit and veg waste) was easily consumed by the (then small) worm colony. 

The benefit in all of this is allowing even the bad bugs and fungi, molds and bacteria to exist, and find a balance before returning it to your garden. Even things like powdery mildew are eaten by some insects or other fungi, so by allowing those to flourish, you’ll find some balance. If you have the time and the ability, take a soil sample, put it in the fridge to cool things down then look in a microscope. You’ll be amazed what’s in there. Then take a sample from a compost heavy area and compare – you’ll be floored! 

So, keep up with the composting and if you’re interested in vermiculture, read these:

Vermiculture: The easiest way to save the world.

Worm Bins: An update

Speaking of patience…this guy doesn’t have much. He does have strawberries and tomatoes at his fingertips, though.

Thresholds, Patience and Tolerance.

Here’s the academic part. Attracting beneficial insects and mites sometimes requires a change in the way you think, react, or view your garden. It starts with determining your thresholds.

Economic Threshold. 

Few home gardeners care much about an economic threshold. Commercial growers know that some pest damage reduces yield, but the cost of getting rid of those pests is more expensive than the loss in yield. But when that loss of yield is such that one must act, they are said to have reached their economic threshold. 

To the untrained eye: it’s time to act. But have patience. There is evidence of an aphid parasitoid, two hoverfly eggs and two hoverfly larva. This aphid colony will be gone in days with no action on my part. (and it was)

For a gardener, you may be willing to spend money protecting a plant you just bought, or maybe you have a favourite plant and you’ll spend whatever it takes to keep that baby alive. Or, maybe this is your hobby, and you allow yourself certain expenditures. Lastly, you may sell produce or cut flowers, and a damaged flower is a lost sale. In these cases, you do need to determine your economic threshold. Will you buy beneficial insects to take care of your problem, or a chemical spray? How much will you spend and when is pest pressure so much that the action is required.

Cosmetic Threshold.

More likely, you have a cosmetic threshold. Maybe aphids in your big leafy tree doesn’t concern you until the week before you host a party and there is sticky aphid honeydew on your patio. Maybe you belong to a rose club, and a single aphid on a rose is a blemish you’re uncomfortable with. Perhaps, like me, holes in your cabbage are ok, but the Swiss-cheese look is where you draw the line. As above, you need to think ahead about these thresholds. They may vary from pest to pest and plant to plant, but know ahead of time when to act.

This was mid-summer, 2019. A very product garden!

The point in considering both thresholds is because nine times out of ten, when people do this, they incidentally end up having to make no action whatsoever.  And that’s because most pest problems (outside) figure themselves out…eventually.

It’s the “eventually” that is at the core of patience. If you can wait, do. Predators will show up. And in order to wait, you need to establish those thresholds but also understand that with the bad comes the good. Pests are food for predators – the more pests you have, the more predators will come. So be tolerant of the pests in your yard.

Some “bad” wasps are good for your garden. Here one is eating a caterpillar

There are all sorts of conditions that can favour a pest and become a problem, and I’ll save that discussion for a different time, but keep in mind, pests almost never kill an established plant. Pests are almost always a symptom of a greater problem. Some wet-root fruit trees create an alcohol that attracts boring insects. Brassicas in summer heat or acidic soil will attract cabbage aphids…etc. So don’t simply ignore them, but monitor them and be patient and tolerant. 

A hoverfly visiting a marigold

If you have to act, you can always introduce beneficial insects and mites. And we’re happy to help at Applied Bio-Nomics ltd. But other than a few preventative insects and mites that will save you some minor headaches, a healthy organic yard with all the tips I have presented should require no interventions. (But please remember, don’t buy ladybugs.)

Attracting Beneficial Insects and Mites is best done by just creating more and better places for good bugs and bad bugs to live. Plants variety of flowers that produce at varying times; establish and maintain a water feature and provide structures if you want to target specific bugs ore need those habitats; ensure you have other, non-flowering plants, or at least a variety of perennials; compost, and return that compost to your healthy soil; avoid damaging practices or chemicals (including soaps and oils) that are detrimental above and below the soil; replace or amend and reduce that lawn; and finally, employ patience and tolerance towards the good and bad bugs. They are all part of the puzzle.

I hope more people would proudly announce good bugs are at work in their yard.

Let me know what you’ve done to attract beneficials and how successful you’ve been!

Read more:

Alternatives to Ladybugs

Using Beneficial Insects in your Garden

The many colours of harvest

Missed one?

Attracting Beneficial Insects to Your Garden:

Lesson 1

Lesson 2

Lesson 3

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