Do Seed Bombs Really Work?

I feel terrible about saying this out loud, but it’s been bothering me for a VERY long time, and I finally just have to admit it:

I kind of don’t think that seed bombs work.

So, Seed Bomb 101 for those who aren’t as obsessed as I am: seed bombs are little balls of compost and clay (or sometimes papier mache) with seeds embedded. The theory goes that you toss them in a neglected green space as an act of guerilla gardening; the clay keeps the seeds moist as they germinate, the compost nourishes them, and they grow, implanting themselves into that green space, making it pretty, and providing valuable food for bees and birds.

It sounds so lovely, doesn’t it? And it’s an easy craft, perfect for preschoolers or day camps or Girl Scout troops (which is how my obsession began, researching activities for the Junior Flowers badge for my troop).

And the seed bombs are pretty, so they make lovely party favors or wedding favors or homemade gifts.

Except… Science.

Here are my two Scientifical Concerns, which I would love, by the way, to have Scientifically Rebutted by a knowledgeable commentor so that my Girl Scouts can go ahead and make their dang seed bombs, already!

I might have some bad news about seed bombs.

1. Germination. Seeds require moisture to germinate. Germination is a delicate process, however, and if the seed dries out while in the process of germination, then germination ceases and the seed dies. This is why you have to keep the soil moist when you’re starting seeds, and why those little greenhouse roofs that you can put over seed starting flats are so handy.

Recipes for making seed bombs require moisture. The most common type of recipe calls for compost mixed with a clay slurry and formed into a ball in which the seeds are embedded. Then, you generally let the clay dry out–the understanding, with most of these tutes, is that the seed bomb is then “shelf-stable” and can be used at your leisure.

Another variation on this recipe uses paper instead of clay and compost–essentially, you mold papier mache and insert or stick the seeds to it, then let it dry.

To my mind, then, this moist environment of the seed bomb begins the seed’s germination. If you then let the seed bomb dry out, or even if you toss it while damp into a green space that then does not immediately get some good rain showers, the seeds will cease germination and die.

So the seed bomb doesn’t work, at least not as generally advertised.

2. Overseeding. Let’s say that it does work. Here’s my next problem:

Many seed bomb tutorials call for a mix of seeds, and they call for many seeds per seed bomb. This means that even if the seed bomb worked exactly as advertised, what would sprout will be six to a dozen or more seedlings, of different types, all in about an inch of green space.

Well, they’ll strangle each other, right?

A lot of my doubt is stoked by the fact that I can’t find many seed bomb success stories online, nor do I know by word of mouth of any acquaintances who can tell me seed bomb success stories. Mind you, I have seen a couple of success stories online, and this has inspired me to think that perhaps, with exactly the right structure under exactly the right circumstances, seed bombs *could* work, and I’ve got a couple of experiments in progress, one that requires the seed bombs to be made and then deposited immediately, with rain imminent, and another that uses only dry materials, but mostly, for most seed bombs under most circumstances, I suspect that they’re just a fun thing to make, that makes you feel good but has little effect.

Am I wrong? Tell me that I am! Give me anecdotes! Give me evidence! Be very Scientifical in your speech, so that I believe!

Republished with permission from Crafting a Green World, Creative Commons photo by Kevan

100 comments

Sara B.
Moody B2 years ago

I still want to try them- I wonder if the bomb was constructed in such a way that the seeds don't come into contact with water until ready, it would work? I like William Miller's idea of a tissue paper bomb, and there's instructions for a bomb made from eggshells if anyone is interested http://www.guerrillagardening.org/tips/seedgrenadekit2.pdf

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Sara B.
Moody B2 years ago

I tried it last year, and I didn't have much luck, but seed bombing is widely used for things like reforestation, so it must work. I found out the hard way that, while they protect the seeds from birds, they don't deter rodents! I'll be adding cayenne pepper to my next batch.

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Sara B.
Moody B2 years ago

I still want to try them- I wonder if the bomb was constructed in such a way that the seeds don't come into contact with water until ready, it would work? I like William Miller's idea of a tissue paper bomb, and there's instructions for a bomb made from eggshells if anyone is interested http://www.guerrillagardening.org/tips/seedgrenadekit2.pdf

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Emily J.
Emily J2 years ago

I still want to try them- I wonder if the bomb was constructed in such a way that the seeds don't come into contact with water until ready, it would work? I like William Miller's idea of a tissue paper bomb, and there's instructions for a bomb made from eggshells if anyone is interested http://www.guerrillagardening.org/tips/seedgrenadekit2.pdf

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Sarah Hill
Sarah Hill3 years ago

I have never used them, not sure I will.

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Siyus Copetallus
Siyus Copetallus3 years ago

Thank you for sharing.

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Tanya W.
Tanya W3 years ago

Thanks

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Sen Senz
Sayenne H3 years ago

I still think there are ways to do it right

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Carole R.
Carole R3 years ago

Thanks for the post.

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Dt Nc
Dt Nc3 years ago

Thanks.

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