How to make seed bombs
A seed bomb workshop needs three ingredients, two days of patience and no prior knowledge at all. Here is the recipe I have used in my own workshop for years — with quantities that actually cover a group. Seed bombs, seed balls, seedballs: it is always the same ball of soil, clay and seed.
How the workshop runs
Gather the materials
For about thirty balls you need five handfuls of clay powder or loam, three handfuls of fine peat-free compost, one handful of seed and water. Add a large bowl, a baking tray and newspaper for the table.
Mix dry first
Combine clay and compost in the bowl until the colour is even. Only then fold in the seed, so it spreads out instead of clumping together.
Add water in small sips
Add water a spoonful at a time and knead with your hands. The mix is right when it holds its shape and no longer sticks to your fingers. Too wet turns gluey, too dry falls apart.
Roll the balls
Take walnut-sized portions and roll them round between your palms. Children's hands make smaller balls — that is perfectly fine, they germinate just the same.
Dry for two days
Lay the balls on the baking tray without stacking them and dry them in an airy, shaded spot. Never use an oven or direct sun: heat damages the seed.
Wrap them or throw them
Once dry they keep for months. In paper bags, jars or jute pouches they become favours. To sow, simply place them on loose soil and water them in.
Quantities, time and effort
A workshop with ten people takes about forty minutes, a school class needs a good hour. Rolling happens standing up, drying happens elsewhere — the table is free again straight after.
How much material do I need for a school class?
Count three to five balls per person. For twenty-five children you need roughly four kilos of clay powder, two and a half kilos of peat-free compost and a hundred grams of seed. Allow a good hour per group, plus two days of drying.
Which seed works best?
Annual native flowering mixes with no chemical seed treatment. Open, single flowers give nectar and pollen — filled ornamental varieties are worthless to insects. Avoid species that are not native where you live.
What is the right ratio of clay to soil?
Five parts clay to three parts compost and one part seed works well. More clay makes the ball sturdier, more compost makes it crumblier but richer in nutrients.
Can I order ready-made seed bombs for a workshop?
Yes. If there is no time or space for rolling, you can have them ready rolled: twenty, forty or a hundred loose balls, with your own tag if you like. Just tell me how many people you are planning for.
Can the finished balls be thrown anywhere?
On your own land yes, on other people's only with permission. Nature reserves, field margins and protected vegetation are off limits. A balcony, a raised bed or your own garden is always fine.
A hundred loose balls, with your own tag if you like
If there is no time to roll, I will do it for you. Loose seed bombs start at twenty pieces, and larger quantities are available for weddings, company events and club parties.