Urban Greening Through Seed Bombs

Guerrilla Gardening and Seed Bombs


There's a movement afoot called urban guerrilla gardening and its goal is to "green" unsightly vacant lots, sidewalks, neglected planters and run-down areas. This is done by using some stealth, seed bombs (earth truffles), and sometimes a slingshot. If you're tired of ugly urban deserts this may be the solution for you. Although it's not really time time of year to be planting it's the perfect time to be thinking about gift giving. Why not give the gift of greening with seed bombs?

What are Seed Bombs?

Seed bombs are rolled up balls of clay, compost, and seeds dried into a semi-hard ball. You can make them at home in a variety of ways with a variety of seeds (see "How Do I Make Seed Bombs" below). Most seed bombs are about 3/4-1 1/2" in diameter and are dried compacted balls that are sturdy enough to withstand throwing or minor impact. I've also seen seed bombs that are made with recycled molded paper as well as tea bags. There are many creative ways to get your seeds out there.


What types of Seeds are In Seed Bombs?

The seeds in seed bombs should vary by eco-region (where you live), sunlight availability, and moisture availability in the area you're "bombing." Hardiness of the plant is also an important factor in choosing seeds. Remember ALWAYS USE NATIVE SEEDS FROM YOUR REGION. It's important that whether you're buying your seed bombs or making them that you always go native. Invasive plants can take over an area and make the it even more run-down and overgrown, which defeats the point of urban greening.

I've seen a range of seeds in seed bombs from tree seeds to edible herbs and flowers. The seeds you can use really depend on the natives in your area, the sun and soil conditions, and amount of shade. Many seeds are perfectly made for sandy or dry areas like vacant lots.

Dan_H flicker(Photo: Dan_H Flicker common use)

Here are some ideas for seeds to include in seed bombs (check to be sure they are not invasive before using):

For sunny bright areas:

  • Marigold
  • Black-eyed Susan
  • Corn Flower
  • Echinacea
  • Chickory
  • Wild Anemone
  • Eastern Bluestar
  • Mullein
  • Joe Pye Weed
  • Milkweed
  • Queen Anne's Lace
  • Arugula

For dark or shady areas:

  • Wild Ginger
  • Wood Violet
  • White Wood Aster
  • Christmas Fern
  • New York Fern
  • Lemon Balm
  • Mint
  • Thyme

Many garden centers offer seed mixes which you can use or you could take the kids to the hardware store and have them help you pick out seed packets for putting into the mixture. Sunflowers are always a favorite.

How Do I Make Seed Bombs?

Gather together the following for a 5:1:1 ratio mixture:

  1. 5 Parts Clay (this can be face mask clay, potters clay, or non-toxic modeling clay from the craft store) Hint: you can also find clay powder at most health food stores in the beauty section in green, red, or white.
  2. 1 Part Compost (make sure it's fine and doesn't have big chunks or peat) or worm castings
  3. 1 Part Seeds
  4. Mixing bowl
  5. Seed soaking bowl
  6. Filtered Non-chlorinated water
  7. Baking tray it's OK to get dirty

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(Photo: Hugvok Flicker common use)

Making Seed Bombs to Use Right Away:

Step 1.The night before you intend to make your seed bombs soak your seeds either in water or a nice compost tea.

Step 2. Pat the seeds dry and then combine  them with clay and compost (5 parts clay:1 part compost:1 part seeds ratio).

Step 3. Use water to lightly moisten the mixture until you can pinch off 3/4-1 1/2" balls and roll them in your hand.

Step 4: Place seed bombs on a tray and allow them to dry in a sunny and warm location overnight. They should be ready to use the next day.

Making Seed Bombs to Use Later or Give as a Gift:

Follow the same instructions as those above, but you'll want to bake your seed bombs in the oven, at 250 degrees, for about 15-20 minutes (depending on moisture content). I like to wrap my seed bomb gifts in colorful paper or hand-made containers. You could make seed bombs for different seasons or eco-regions to send to friends and family.

What if I don't Want to Make My Own Seed Bombs?

If you don't want to make your own seed bombs you can buy pre-made and pre-packaged ones (or entire kits) from a variety of companies online including ThinkGeek. My favorite store is a non-profits called Greenaid out of California. Even though they're not local they're doing a great job in their seed bomb business. They use eco-friendly materials and their employees are from Chrysalis, a foundation for formerly homeless and disadvantaged men and women living in the Los Angeles area. Proceeds go for a great cause.

I like that Greenaid also has a unique way of distributing their seed bombs. They have placed seed bomb vending machines all over the US. I even found some in Baltimore and DC! Click here to look at their map of locations and deployed seed bombs.

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How Do You Deploy Seed Bombs?

To deploy seed bombs you need a bit of pre-planning and scouting. It's best to deploy during spring or summer. Make sure that if someone sees you that you won't get in trouble for "littering." Scout the area you think needs some "urban green" or improvement. If you can get a look at the soil conditions, hours of daylight, shade, and moisture level it will help you choose the best type of seeds and seed bombs. Don't try seed bombing in very dry and compacted soil or on completely paved areas. If the location you're trying to seed bomb is behind a fence you may need to use a slingshot or to toss the seed bombs over. Some seed bomb locations are simple, such as abandoned flower beds or along parking lots. Again, be careful not to get in trouble or in areas where people might be hostile to you using your seeds. You can get together a group of friends and sling away if the time and place are right!