Making seed bombs is a great activity for all ages- it’s reminiscent of making mud pies as a kid. You can use any seeds for this activity but we’ve been focussing on native wild flowers which provide pollen and nectar for bees and other pollinating insects.
Seed bombs became popular thanks to the Guerilla gardening movement and it’s global efforts to cheer up neglected or disused plots by sowing seeds in hard to access places. They provide a simple method of distributing seed widely, whilst also providing the soil and nutrient needs to help the seeds become established.
The bombs are generally most suitable for flower beds and gardens- they should not be thrown in wild/ natural spaces without permission as you may introduce plants that could have a negative effect on local wildlife. However, seed bombs can also be used to help disperse wild flowers more swiftly across a regenerating site (which is how we’ve used them). Seeds can be collected through the year as plants mature and stored in paper bags until you’re ready to use them.
You will need:
- Buckets or large bowls
- Water (preferably rain water
- Seeds (either purchased packets or collected by hand)
- Clay (any clay based soil will do. Potters clay or powdered clay also work well)
- Compost (we used bracken compost because we have a LOT of bracken)
Crumble the clay between your fingers to break up any clods. Take out small stones, roots, earthworms and any other mini-beasts at the same time.
Mix together 1 loose handful of seeds with 1 handful of compost and 5 handfuls of clay. Make sure you thoroughly combine all the ingredients and break up clumps of seeds so they are evenly distributed.
Add sufficient water for the mix to hold together in a ball; rather like making stuffing balls. Remember they need to be firm enough to throw so don’t make them soggy. If you add too much water you can dry up the mix by adding more compost.
Mould your mixture into balls around 4-5 cm in diameter. Make sure they firmly hold together- you don’t want them to disintegrate in mid throw! Once you’ve made all your seed bombs you can dry them on baking trays to store for later use or they can be thrown immediately.
The best time of year for sowing most wild flowers is Autumn. Try to choose a time when rain is expected over the following weeks (Autumn is generally very accommodating with this). When throwing your seed bombs try not to smash them onto the ground- you want them to have soil contact but not disintegrate into tiny pieces.
You can find further instructions for collecting and storing wild flower seed at Kew’s GrowWild site.
The Bumblebee Conservation Trust site has lots of information on gardening for bees and other pollinators, including suitable plants to grow and guidance on how to best manage land for wildlife.