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Why seed bombs don’t work

I love the idea of seed bombs. The first time I heard about them I wanted to go out and toss them everywhere, but at the same time, I knew they wouldn’t work. Actually, they will work in places where you don’t need them, but will almost never work in places you do.

More often than not, people are encouraged to throw seed bombs into vacant lots, abandoned industrial sites, roadside verges and medians, grassy wastelands, and trampled playgrounds. These places are the least likely to produce results.

Why bare ground stays that way

Most bare ground is bare for a reason. To begin with, many of these areas have dense layers of traffic pan. Traffic pan is an agronomist’s term for soil that has been heavily compacted by repeated and frequent use. Roads, industrial sites, and fields frequently traversed by tractors, cultivators, harvesters, or trucks all are subject to traffic pan. Even footpaths, playgrounds, and ball fields develop it.

Traffic pan makes it hard or impossible for seeds to start. The compaction itself can prevent tender young roots from penetrating the soil, and the layer can act as a barrier to water and air, causing puddling above and dryness below. Certain plants manage to break through these dense layers, but they are usually not the ones you want. Most often, traffic pan needs to be broken up by mechanical tilling. If not, seeds landing in these areas may germinate, only to die when the roots fail to penetrate the soil or when they are washed away by a heavy rain.

The things we don’t see

Industrial sites may be polluted with chemicals or waste products that prevent germination or inhibit growth. Toxic substances may have destroyed beneficial soil organisms while other chemicals may have altered the pH. In addition, these areas may be too sunny, too shady, too wet, or too dry. They may still be driven over, walked on, or peed on by every passing pooch. The seeds or young shoots may be preyed upon by birds, rodents, squirrels or other hungry city-dwellers. Remember that farmers and gardeners work hard to get results, and they continually fight against the elements, predators, pests, and pathogens. They don’t just stick seeds in the ground and walk away.

Roadsides are often sprayed by city or county agencies in the name of weed control, so planting seeds in these areas may be for naught. Utility easements are often sprayed as well, usually to keep down fast-growing trees, but the herbicides they use are not selective for one particular kind of plant. And since seed bombs are not (or should not be) made from invasive species, there is no way that seeding a field of invasives will do anything except give the existing flora a little jolt of fertilizer.

Fertile fields are not much better

Although it may seem counterintuitive, abandoned fields—especially those that were fertilized in the last decade or so—are also poor places for seed bombs. Many wildflowers such vetch and clover are nitrogen fixing. Since these plants can produce all the nitrogen they need, they can effectively compete against other plants in areas where nitrogen is otherwise scarce. All else being equal, plants like the grasses can’t even get started in these areas. But once a field is artificially fertilized, the grasses take over with a vengeance and quickly out-compete the wildflowers.

In his engrossing book, A Sting in the Tale: My Adventures with Bumblebees, Dave Goulson explains this conundrum in detail, and he emphasizes just how hard it is to grow wildflowers in a field that was once fertilized. As he says, “There is no easy way to reduce the fertility of soil in a meadow, yet it is impossible to recreate a rich flower community without first doing so.” He goes on to explain how the process of reducing soil fertility can take many, many years.

Placement makes a difference

I’ve had people protest that they planted seed bombs in flower pots and garden beds and they grew “beautifully.” No doubt this is true. But the idea behind a seed bomb—that we can distribute pollinator plants far and wide by throwing clay-encrusted flower seeds into waste areas—is a happy thought that is mostly just that, a happy thought. The law of unintended consequences is hard at work here: by “improving” the land for various uses, we have destroyed its ability to produce the historic native landscape we are now seeking.

If you want to toss seed bombs, go for it. After all, it is fun to throw things: “Take that, you nasty piece of plantless dirt!” But if you really want to help the pollinators, a little more thought would go a long way to achieving success.

Rusty
Honey Bee Suite

Compacted-soil-with-weed-Pixabay
Compacted soil does not absorb water easily. Because it tends to puddle on top and remain dry and powdery below, few plants can live in it. Pixabay photo.

Comments

Bill
Reply

Rusty, As always nice job telling us about the woes of seed bombing. The plant in the picture looks like Curly Dock, a source for Oxalic Acid. By the way did you get the email I send about the temp & humidity graph?

Rusty
Reply

Bill,

I will have to check on that. My HBS inbox is kind of a scary and intimidating place, and things do get lost.

Mary Kay
Reply

I dunno about this although it sounds logical. This summer I tossed some wildflower mix around where the bottom of my last manure pile had sat for a couple of years, as I took it away to different uses. Those seeds came up, flourished, and are on their second generation now. Underneath was basically hardpan, which probably did soften under the manure influence.

Wayne
Reply

I am the “Dutch Clover Bandit”. If White Dutch Clover is frost seeded along limestone gravel covered road edges in February, it will grow prolifically the same year. A good time to put it out is right after a big snow before the plows come through. When the state or county mow, it produces blooms all the better. It blooms some the first year and more every year after. Clover likes a higher pH, which is why it does so well. This low growing variety used to be put in lawn seed mixes until everyone wanted a weed-free yard in America. Grab a bag and throw in the floor board too. Nothing like the wind from passing vehicles or a snow plow spreading some love for your bees.

Mari Vega
Reply

I’d like to relate the following because of how closely it relates to your article here.

I’ve had the honor of knowing artist, Mr. Chapman Kelley, who worked together with a scientist, volunteers, and sympathetic funders to make a living painting in Chicago’s Grant Park using native plants. He says the genesis of the idea was a talk given by Buckminster Fuller about intuition. In the 1970s, Chapman’s concern was for the coming water crisis. How prescient!

The Wildflower Works garden flowered 3 seasons out of 4 and had daily observation and maintenance, but, once established and because they weren’t even using the tap, they requested in writing that the City turn off the water to that area. It lasted for some twenty years like this until the City tore it out. Alas, Chicago subsequently replaced it with another project by a different artist–this one with hybridized and imported plants.

He has recounted much of his illustrious career on his website, linked above but, suffice to say, it does take a lot of time & careful attention to make wildflowers grow–especially in populated areas, as you wrote.

Chapman Kelley is still committed to saving water. Imagine how much potable water could be saved if people were not watering their lawns!

Thank you for reading this share, and for the article that inspired it.

Nancy Celani Baker
Reply

Darn. I always wanted to throw seed bombs. It seemed so neat. But thanks for the info. Now I can scratch one more thing off my to-do list and not feel guilty 🙂

John Lucas
Reply

These things are spelled out in the bible.

Nancy
Reply

That does, indeed, appear to be Curly Dock, one of the first weeds to get established on bulldozed subsoil when the funding for the new strip mall falls through. Its taproot can pierce hardpan and bring minerals to the surface, helping to create new topsoil. It’s usually followed by the Knotweeds (close relatives).
Sadly, it’s not much use to pollinators as the flowers lack nectar and the pollen is wind-dispersed.
Nan
Northern Kentucky

Militoy
Reply

Hi Rusty –
I had never heard of “seed bombing” before – but after reading your article realized that I practiced a similar hopeful action for several years. I live in a very rural part of the Mojave Desert in California. We have many years with abundant grasses and noxious weeds – and a few in between with an explosion of wildflowers. One patch of ground at the north end of a property I own has been plagued by a carpet of fiddlenecks for years – no matter what was blooming in the surrounding acres. For two years, any time it theatened rain, I hand-cast a couple pounds of native arroyo lupine seed (easy to get) over the area. During the next two wildflower blooms, the fiddlenecks were mostly replaced by a 10-acre carpet of lupine. Since this is shaping up as an “El Nino” rain year after a long drought, I’m holding my breath to find out what grows there next spring.

Scott
Reply

There is a large lot behind my tract home that is just grasses. I would love to take a trespassing stroll through the lot to plant wildflower seeds but I would truly hate to see my efforts mown down! The property owners mow the empty lot(s) several times a year. Otherwise I would be out there! Throwing seeds to the winds!

annika
Reply

When used for permaculture seed bombs/balls are great, but it’s ILLEGAL to dump seed bombs on private property, as you correctly stated. Dumping is a TRESPASS. Here’s what’s going on in my part of the upper middle class world: whenever a neighbor has a problem with another neighbor he or she bombards their neighbor’s house with seed bombs. Seed bombs not only ruin landscapes that cost thousands of dollars to plant but they also invite rodents. That’s correct–rats, white footed mice, brown mice, chipmunks, rabbits, squirrels, many birds and their predators are attracted to seed balls/bombs. The rodents chew up expensive roots on bushes, trees and herbaceous plants as they desperately try to eat all the seeds and moss. Rodent’s poop also attracts their predators, and those predators tear up the garden looking for rodents. Seed bombing private property other than yours can cause the destruction of property and it is illegally dumping. Dumping is against the law and you can get a fine, arrested or sued for such acts. As for children, anyone teaching them to throw seed balls on private property other than their own, is encouraging bullying and unlawful behavior, and therefore corrupting minors.

Rusty
Reply

Annika,

Really? People in “upper middle class” neighborhoods seed-bomb their neighbors? What you describe sounds low class to me.

annika
Reply

As if this is not bad enough some have decided to throw glass shards inside the seed balls.

Very upsetting. I’m talking about lawyers, doctors, college professors, psychologists, scientist, horticulturists, real estate agents, builders, contractors, etc.; it’s extraordinary how some people are all about retribution. The sad thing is that it successfully puts fear into people so we do nothing even though we know what’s going on. We are scared of becoming a target as well. This is the best I can do to get the word out to caring law-abiding people to discourage such behavior. Thanks for your support.

Rusty
Reply

Annika,

“I’m talking about lawyers, doctors, college professors, psychologists, scientist, horticulturists, real estate agents, builders, contractors, etc.”

So interesting. To me “class” is a standard of behavior and decorum, not a resume or job description. A high salary or a fancy title does not automatically confer class, as you have just illustrated. Some of the classiest people I have known were stone broke.

Annika
Reply

Indeed!

Rajesh RK
Reply

I really came to know much about seed bombs by this article & comments as well. I got enough information what I really need. Thanks alot!

Ben
Reply

All fair points but the sentionalist headline isn’t fair. ‘Seedballs don’t work in certain places, for certain reasons’ would have been fairer.

Because they do work but not everywhere.

Geoff
Reply

I make my seed bombs from used teabags. Just make a small cut and put a handful of seeds in of native flowers.

I am fortunate that the large city I live in has protected green space along the river systems flowing to a Great Lake. I fish a lot on these river systems, so I always bring a few seed bags with me and throw them in the soils along the riverbank. Certainly not all bloom and some flowering plants hold better than others, but I am there anyways fishing and have had good luck over the year seeing new flowers develop.

Rusty
Reply

Geoff,

What a totally cool idea. I assume that the tea bags are still wet when you seed them? It’s like a little sack of damp peat moss.

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