Module 7: Pollinator & Predator Habitat
Creating a wild kingdom.
Life of a garden bug, Part 1.
Imagine, for a moment, that you are a tiny insect who nonetheless inspires fear and loathing in the hearts of gardeners: a hornworm. It's early summer and the season's first tomatoes, your favorite food, have just begun to ripen in the hot sun.
As dusk falls, you peer out from the shelter of a mite-infested rosebush and spot your dinner hanging in a tight cluster from a staked branch. The 'maters are still a little green, but that's just when you like to get them--right before the gardener picks them.
Unimpeded, you make good time slithering across the short stretch of freshly mowed lawn and up a smooth plank border to the immaculately weeded garden bed. An army of aphids is silently laying waste to a row of romaine lettuces while a mob of mealybugs chows down on the root vegetables. A gang of stinkbugs trundle quickly over the bare soil to the potato patch. Overhead, a ghastly horde of gypsy moth caterpillars audibly munch the leaves of an apricot tree.
You are in no particular hurry. It seems as though this garden was planted just for you and your hungry cohorts. With nothing in your way and nowhere for predators to hide, you glide leisurely around the buffet of tender vegetables to arrive at the tomato plants, climb aboard a low-hanging fruit, and chomp your way inside.
Delicious. And the night has just begun.
Life of a garden bug, Part 2.
Now, let's imagine another scenario. You are the same hornworm, but the tomatoes you crave are now at the far side of a very different lawn and garden.
As dusk falls, you peer out from the shelter of a hardy nitrogen-fixing pea shrub. Past the treacherous landscape studded with dandelion and blue speedwell flowers, you can just barely see a cluster of tomatoes behind a wall of herbs. It seems so far away. Warily, you set out for the garden.
Signs of danger greet you at every pass. Moving cautiously through a patch of clover, you encounter a big-eyed bug on the prowl for mites. Your relief at reaching the stones that edge the garden is quickly quelled at the sight of ladybugs feasting on aphids under a low shelter of ajuga and sedum.
Just beyond the border, hoverflies and lacewings lurk in a thicket of lavender and yarrow, intercepting the mealybugs headed for the root patch. Overhead, a squadron of bristled tachnid flies rises from their launchpad of parsley and thyme and injects their eggs into the gypsy moth larvae climbing the apricot tree.
Slithering as quickly as you can past the carnage, you finally reach the interior of the garden. The plump new tomatoes beckon. But, too late, you see the plants are surrounded by a fortress of fragrant herbs: basil, fennel, coriander, and dill. From their watch in the fortress, a brigade of braconids, tiny brightly colored wasps, spy an invader--you--and descend to do their part in maintaining the balance of predator and prey.
I use these two scenarios to illustrate rather vividly how a diverse ecological garden, designed to feed both humans and wildlife, is more useful, beautiful, and resilient to pests than a garden planted to grow food only for people. Here are some ecological truths we can glean from these scenarios and how we can make them work for us.
Nature strives for balance.
If we followed our first imagined scenario through to its logical conclusion, eventually the garden vegetables will be completely decimated by pests. What remains will make good compost for weeds and wildflowers bouncing back that house predators. The predators will then check the pest population until an equilibrium is reached.
Lesson: Once you understand how a natural ecosystem works towards balance, you can anticipate and mimic nature's patterns to achieve a desired result. To control garden pests, provide food and habitat for their predators.
Prescription: In an ecological garden, plants we think of as "ornamental" — flowers especially — are actually food and habitat for beneficial insects. Pollinators are attracted to blossoms showy or demure, from brilliant cosmos to modest thyme flowers. Every food garden needs a fair share of herbs and flowers. Plant for flavor, fragrance, and beauty as well as sustenance and you will be rewarded with all of it.
In addition, many predators that keep mites, aphids, mealybugs, and hornworms in check shelter under stones, leaf litter, and mulch. Not only does organic mulch suppress weeds, retain moisture, and build soil humus, it provides cover for beneficial predators! Remember, Mother Nature is not Martha Stewart. A tidy, hyper-organized garden is an inefficient garden. Keep your soil "littered" with leaves and mulch for multiple high-performance functions.
Nature is more effective than benevolent
Honestly, my patience with people who espouse a unicorns-and-rainbows view of nature's ways has grown rather thin. I find that the vast majority of people who believe in a benevolent Nature have very little experience — if any — working directly with the elements. You've probably noticed I use words like "weeds" and "pests" without hesitation because I know what it's like to lose a crop to ravenous insects and see plants suffocated by vines. I want to help you prevent these calamities by showing you how to create a resilient ecosystem — that also happens to be a food garden.
It's true that we can observe many wonderful examples of symbiotic relationships in nature. And we can also observe ruthless competition and stark predator/ prey dynamics. To claim that nature is only benevolent is both naïve and delusional.
Lesson: Nature doesn't give a fiddlestick about you or your vegetable garden. She has her own plans. To get what you want from nature, you have to work with her.
Prescription: Observe, observe, and observe. In order to work with nature's patterns, first you have to see them. Once you can assess a problem, you can adjust your garden accordingly. Cultivate patience, dispassion, and prudence. Try not to overdo.
But what about natural pesticides? Can't I just spray something? Or aren't there any plants that repel insects?
Well, let's see about that...
The Problem with Pesticides
Simply put, if you don't want bugs eating or spoiling your fruits and vegetables, you need to invite in the good bugs that eat the bad bugs. You can do this by providing food and shelter for beneficial insects with densely planted "thickets" of flowers and herbs, mulch, leaf litter, border plants, and stones.
I firmly believe in this ecologically-minded method of pest control. I've seen it work on all scales, from tiny urban gardens to the large-scale regenerative farming I do now.
However, experience has shown me there is a fly in the ointment: creating an ecological balance of predator and prey takes time. If you have just planted your first garden, you have likely focused primarily on annual vegetables, a favorite food of many insects. You see the error and want to adjust by planting more predator-attracting flowers and herbs, but in the meantime your tender new veggies are an aphid-chewed, wormy mess. Now is that precarious time when the urge to spray pesticides might just become too strong to resist…
Stop. Right. There.
Well, wait at least, just for a moment. Because I'm going to tell you exactly why once you climb on the pesticide roller coaster, there is no getting off. Really, it doesn't matter if we are talking about petrochemical-based pesticides or natural sprays, my aim is to discourage you from using either. First, I'll explain why and secondly, I'll offer some solutions.
Ok, so maybe you're thinking, what's wrong with using a natural spray, especially a home-made one?
Well, there's nothing wrong about it on moral grounds. I simply don't find them very effective. I've tried them all: chile pepper, garlic, neem oil, baking soda, diluted soap, etc. I'm not saying they don't work at all, they just don't work very well in relation to the amount of time and effort you have to put into acquiring, making, and applying them.
Natural pest repellents need to be applied almost constantly to have any noticeable effect. They wash off - all it takes is a few hours following a summer thunderstorm for pests to make a meal from your recently-sprayed garden. Unlike ground beetles and ladybugs that eat bugs that hide in the soil, natural sprays do nothing to deter insects that eat or infest plant roots.
Another factor to consider is that going out to the garden armed with sprays to kill bugs is a chore; it's just not fun.
The bottom line is: there is simply no substitute for an ecologically harmonized garden growing in healthy fertile soil. Why spend time, energy, and money "fighting" a losing battle when you can expend those precious resources building resilience in your garden?
Just like the Discovery Channel
Pesticides, natural or chemical, are not very effective — especially in the long term — and have disastrous side effects. Here's why:
Think about the last time you watched a nature documentary showing lions or cheetahs stalking their prey on the African savannah. It's always a few big cats and a whole herd of wildebeest or gazelles, right?
Well, the insect world is exactly the same. Not only do the pesky bugs that eat your veggies vastly outnumber the carnivorous predator types, they also have much shorter and more prolific breeding cycles. In a diverse ecologically balanced garden, that's OK. One ladybug larva, for example, can consume up to 500 aphids per day. But in a vulnerable garden with a spray-dependent gardener, it's a recipe for disaster.
So what does that mean for you and your "pesticide" spray? First of all, there is no such thing as a pesticide. There are insecticides: sprays that kill ALL insects: predator, pollinator and prey, beneficial and harmful alike. Let's be clear about that. And the natural formulas that repel unwanted pests are equally repellent to their natural predators.
Let's say you spray your garden and eliminate most of the insects. Your cultivars get a respite for a few weeks and start looking pretty good. You're happy with your spray bottle and write a five-star product review. Then the hungry invaders come back, more numerous and ravenous than before. You spray more vehemently. The cycle repeats itself, each time the pests return with more reinforcements.
Now you find yourself spraying more regularly just to squeeze out a harvest in between invasions. You make a spraying schedule on your calendar. The instructions on the bottle caution you to wear gloves and not to inhale the contents. You have to keep your children and pets away from the garden. What you imagined as a backyard Eden has become a hazard zone. Finally, you return from a short summer vacation to find that the nibbling, munching, chomping horde has returned, stronger than ever.
How is this effective? Or enjoyable?
What happened? It's actually easy to understand if you remember the lion/gazelle analogy, the ratio of predator to prey. While the insecticide kills most of the bugs, a few escape annihilation. Of the survivors, the prey insects — the pests — breed and multiply rapidly. The predator insects are outpaced.
With each successive spraying, the imbalance becomes more pronounced, until eventually the struggling predator populations collapse completely and their prey is left to multiply at will.
The data bear out the hypothesis. Over the past fifty years in the U.S., crop loss to insects has increased from 7 to 14 percent, even though insecticide use has increased two-fold as well.
Think about that.
Double the amount of insecticide, double the amount of crop loss to insects. Heavy insecticide use, combined with soils depleted by monoculture farming and clear-cutting of forests has brought us to this dismal place. Your garden isn't very different from a farm, only smaller. You have an opportunity here to show how diversity and balance — nature's tools — are the most effective.
Ok, ok. You've convinced me. But I just planted my first garden and I didn't know about attracting good bugs. What can I do NOW?
Don't worry. Here are some accessible ways you can jump-start your ecological garden, along with a few short-term pest solutions that work.
Quick Ways to Control Garden Pests
Use perennials as "anchors" and fast growing annuals to fill in the gaps.
Get your mini "thicket" of predator/pollinator attracting herbs and flowers started with a few selections from a nursery or home improvement center. I'm all for starting plants from seed, but herbs like lavender and thyme grow slowly. Make a modest investment in some perennial "anchors" and plant them two to three to cluster. Echinacea, yarrow, coreopsis, daisies (anything in the Rudbeckia genus) and all perennial herbs are a good start. In between the clusters sow seed for fast-growing annuals like borage, nasturtium, calendula, speedwell, dill, fennel, and alyssum. Many of these annuals seed in the fall and will return in the spring. Their colorful blossoms, nectar, and foliage will attract a good number of beneficial insects within six weeks!
Use stones, bricks, or pavers to shelter beneficial insects.
The materials you use don't have to be new or in perfect condition. Broken corners and cracks provide shelter for a bevy of good bugs. This is also an excellent opportunity to recycle old or broken materials — many construction sites are only too happy to give them away.
Sprinkle ashes, gravel and charred wood around tender vegetables.
In Chapter 1, I recommended adding charcoal or charred wood from the grill or fire pit to help retain soil nutrients. You can also use the remains of a fire to repel slithering pests like hornworms and slugs. These soft-bodied bugs do not like the feeling of abrasive materials and will shy away from plants ensconced in a protective circle.
Get them drunk.
As a last resort, I have deployed beer traps in new gardens when there was an imbalance of predator and prey. Many insects that eat vegetables also LOVE beer. It doesn't matter what kind. Save your precious IPAs for yourself and give the bugs Coors or Budweiser. Simply bury small (4-6oz) containers in the soil to the level of the opening at the top and fill three-quarters full with cheap beer. Bugs will stop off for a drink on their way to the veggie buffet, get drunk, fall in and die. It's a bit gruesome, but it works.
There's no Magic Formula
Perhaps the site of those insect corpses will convince you like no words can that it is indeed far more enjoyable to work with life than with death. Piecemeal solutions, whether they be insecticides or beer traps, rob the garden of life and the gardener of the sheer pleasure of being in the garden.
A note on plants that supposedly deter pests:
I know some people swear by certain plants as pest repellants, but there is really no evidence to back up the claims. I personally think that many of these folks are missing part of the equation. They see tomatoes they've planted alongside the basil doing well and not getting nibbled and attribute it to the basil, when it might actually be the predator bugs hiding in the basil who deserve the credit.
At any rate, I'm not going to lead you down a primrose path to believing there is an easy just-plant-this-magic-repellant fix to pest problems. A holistic approach that emphasizes a balance of predator and prey will serve your garden more in the long run.
Remember, the real goal is to create an ecosystem, with the emphasis on the system. An ecological garden is a whole that is greater than the sum of its parts. Herbs and vegetables are just one part of the yield. The whole will also deliver resilience, abundance, and joy.