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How to make seed bombs: a DIY guide
If you’re looking for a sustainable, effective and surprisingly fun way to enhance your landscape, consider a wildflower seed bomb. Known traditionally in Japan as tsuchi dango, or "earth dumplings," these compact balls are more than just a gardening trend. They are a powerful tool for ecological restoration. Research Scientist Daisy D’Angelo shares her passion for wildflower seed bombs as a simple, high-impact way for anyone to get involved with gardening and incorporate native plants back into the landscape.
How do seed bombs work?
A seed bomb acts as a self-contained, portable ecosystem. The composition serves two purposes:
- Natural protection: The clay acts as a binder and a protective shell, shielding the seeds from being scavenged by birds or mice.
- Organic nutrition: The compost provides a concentrated burst of organic nutrients exactly where the germinating seedling needs it most.
Once "launched" into a garden or a marginal roadside area, the balls remain dormant until activated by rain and sunlight. As the casing dissolves, the seeds take root directly into the soil.
Benefits of wildflowers and native plants
As they grow, these wildflowers create homes and food sources for pollinators like bees and butterflies and other insects. Beyond supporting local biodiversity, these plants also protect the land. Their deep root systems stabilize the soil to prevent erosion and filter runoff water.
When to plant seed bombs
Strategy is key to a successful "bombing" run. Wildflower seed bombs often benefit from "overwintering." Toss them out after the first hard frost in the fall; they will sit patiently through the winter and sprout at the perfect moment in early spring.
Daisy’s DIY seed bomb recipe: a step-by-step guide
Seed bombs are an excellent craft for families and make wonderful eco-friendly gifts. To create your own, follow this simple ratio:
The Ingredients
- 3 parts local compost (or high-quality in-ground soil).
- 1 part clay powder (red or green craft clay works best; additive-free cat litter works in a pinch).
- 5% seed mix (roughly 1/4 cup of seeds for every 4 cups of base).
- Water (added slowly)
The Process
- Mix: Combine the dry ingredients thoroughly.
- Hydrate: Slowly add water until the mixture reaches a dough-like consistency.
- Form: Roll into small balls (about the size of a large marble).
- Dry: Place on a tray and let them dry for 24 hours before storing in a cool, dry place.
Daisy D’Angelo:
Hi, I'm Daisy D'Angelo, and I'm a scientist on the Gardens Growing Media team. And right now, I'm going to show you how to make a basic wildflower seed bomb.
So in this recipe I'm going to start with a cup of compost, and I'm going to add it into my bowl here. And then I'm going to add a third of a cup of clay.
And then lastly, we add the seed. So in this case we're going to add just under a tablespoon of seed.
And once you have it all together it should look like this. And what I'm going to do at this point is I'm going to mix these ingredients all together while they're dry.
So the compost in the seed bomb works as a nutrient source for your young seedlings, as they begin to grow.
The clay acts as a carrier — once I add water to this mixture, it's going to help really hold the balls together. I'm going to go ahead and add about 40 to 50ml of water. That's about 1 to 2 tablespoons. So then I'm going to go ahead and mix it and incorporate it really really well.
And so once it's all come together I'm able to make seed balls. And this is a very forgiving recipe. So you can add more compost or clay as needed. If you added a little too much water that's completely fine. And once you've formed all your seed balls, they should take approximately 12 to 24 hours to dry.
You can launch them wherever you like, or you can deliberately plant them in your landscape. You can also put them in containers.
So in this mix, we used native wildflower seeds. What's great is now all you need to do is set it out where you'd like it in the landscape, and you've begun your own pollinator patch.
