Get ‘guerrilla gardening’ and make your own seed bomb

February 12, 2014
Author: Hannah

At our Freaky Nature event this half term (15 – 28 February 2013), you can explore the weird and wonderful world of plants, including a special focus on seeds that go bang.

Making and throwing seed bombs is a fun gardening activity for families and communities. When they sprout into beautiful flowers, the guerrilla-style seed bombs can bring colour to a patch of bare land, and the act of making and throwing the bombs adds a sense of excitement to gardening.

Seed bombs next to flowers and a picture of a grenade

You will need:

The ratios below for clay, compost and seeds should be multiplied to make more seed bombs.

  • A bowl: each person taking part needs their own bowl to mix in.
  • Newspaper: to dry the bombs on.
  • Clay: three parts (eg three handfuls). Use terracotta clay powder or air-dry clay (found in art supply or health food stores)
  • Peat-free compost: five parts (eg five handfuls)
  • Seeds: 1one part (eg one handful).
    Tip: Native wildflowers are a nice idea. If combing different species, check that they can all be sown at the time of year you’re planning to throw the ‘bombs’ (different seeds can be sown in spring or autumn – look on the packet for advice). Also think about the type of area you’re planning to plant. For shady spots, choose a woodland mix, for example including foxgloves or honesty. For sunny places, go for meadow flowers such as cornflowers, marigolds or hollyhocks.
  • A patch of land: seed bombing should not be done without permission on land you don’t own. But it’s a great activity for your own garden or a piece of community-owned land that you’re working to transform.

Hands in a bowl mixing soil and making a seed bomb


  1. Mix the compost and the seeds together in a bowl, then mix in the clay.
  2. Add water, so it’s wet enough to stick together, but not too wet so it’s a sludgy mess. It should have the consistency of biscuit dough.
  3. Make sure the seeds are surrounded by the clay and compost, so the bombs can be slowly broken down by the sun and rain to release the seeds.
  4. Shape the mixture into truffle-sized balls.
  5. Arrange the seed bombs on sheets of newspaper and leave to dry slowly for at least three hours (or even overnight) in a warm, dry place.
  6. Throw your seed bombs – ideally, timed to coincide with rain, so the seeds have a good start. (It’s best to use them straight away, as they could start to sprout. But if you do need to save them, keep the seed bombs in a cool, dark, dry place – and not for more than a few weeks.)
  7. Watch for growth. Seedlings should be visible within two to three weeks – and flowers within 12 weeks.

If you haven’t got time to make your own seed bombs, but fancy a go at throwing some, take a look at these Wildflower seed bombs for sale in the Eden Project online shop.

Thank you to Cedim News and Sarah Kanouse for the photos.


3 responses to Get ‘guerrilla gardening’ and make your own seed bomb

  1. robbie says:

    This is great! Could you please give me some advice as to what type of clay to use?

    There are many different sorts and they are recommended for different uses.

  2. Hannah says:

    Hi Robbie, you should use terracotta clay powder or air-dry clay (found in art supply or health food stores).

  3. Pingback: Green Grenades |

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