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Seed Balls

Bob Wildfong

When we need a quick gardening activity for kids that will work rain or shine, at any time of year, that's fun and practical, easy and good for all ages, we make Seed Balls. Seed balls have been around for a long time in one form or another, and they turn out to be one of the best ways to distribute and plant wildflower seeds to make gardens more pollinator friendly. Here's how they work.

A seed ball is just a mixture of clay and compost, with seeds mixed in too, rolled into a small ball so it can be planted later. When the clay dries, the ball hardens so it can be carried conveniently and planted at any time, even months after it is made. That makes it a good craft for kids at gardening events, with a useful takeaway that doesn't cost much to produce.

What You Will Need

Clay: You can buy potters clay at any craft store (use the natural kind, free of plastics, because you'll put it in your garden) or if you can find very heavy clay soil you can just dig that up.

Compost: This is mixed with the clay to allow it to break up easily, but still harden into a ball. Any kind of natural material will work, so if you don't have nice clean compost you can use potting soil, purchased compost, or fine topsoil from your garden.

Seeds: We prefer seeds of native wildflowers, which attract and feed pollinators, but technically you can use any seeds you want. Timing is key - only use annual seeds if the balls are going to be planted in spring - wildflowers can actually be planted at any time of year (they'll wait until the time is right for them).

A container with a water-tight lid: Your seed ball mix will last as long as it stays moist, so keep any leftover mixture tightly closed.

Clean up: Little hands love making seed balls, but they need to be washed up afterward. Also, spread some newspaper on the table to help tidy up when you're done.

How to Make and Use Seed Balls

Mix the clay and compost in about equal amounts. Test the consistency by rolling a ball about the size of a quarter. If it breaks apart while you roll it, use more clay or add a little water. The mixture shouldn't be sticky, but it shouldn't break apart easily.

Before you add the seeds, think about how much mixture you'll use. Once the seeds are mixed in, you have to use that mixture because they can sprout if they're kept moist in the container for more than a few days. Mix about a tablespoon of wildflower seeds per litre of clay-compost, and stir them as uniformly as you can.

To make a seed ball, just take a little clay-compost-seed mix, roll it into a small ball and let it air-dry.

Once dry, the seed ball can be kept for many months and it can be planted anytime and anywhere just by dropping it or throwing it on the surface of the ground where you want wildflowers to grow. Don't plant your seed balls under the ground, just leave them on the surface. Be patient - seeds sometimes take a long time grow, and wildflower seeds like to have a chilly period before they sprout. Fall is the best time, but you can put seed balls in your garden at literally any time of year.

Make sure you use up all of your seed ball mix at the end of the activity. The clay-compost mix can be stored for any length of time in a sealed container, but if you've mixed the seeds in you have to use it up or discard it because the seeds will sprout in the container otherwise. We just roll up the leftover mix to make seed balls that we can give to kids at the next activity. Once dried, the balls are good for at least a year.

The Science of Why They Work

At first, seed balls seem a little unnecessary. After all, if you have wildflower seeds anyway why not just plant them straight away? The reason, as many gardeners have discovered, is that wildflower seeds rarely grow when you simply plant them.

Wildflowers make a lot of seeds. Just take a handful from a plant in the fall and see how many there are. But the fact is that almost none of those thousands of seeds will manage to grow into another plant. Wildflower seeds wait for a long time, until spring, before they sprout and in the meantime they tend to blow away or get eaten by birds and mice. You might try to prevent that by burying them in the soil, but since most wildflower seeds are very small if they're buried too deeply they can't push their way up when they try to sprout. To survive, these seeds have to be under the soil just a tiny bit, but not more.

That's why seed balls work for wildflowers! The cold and wet conditions of winter slowly break down the clay ball, freeing the seeds, but they are protected the whole time from birds, mice, and wind. Then in spring, the remnants of the clay-compost just barely cover the seeds, leaving them in the perfect spot for successful germination.

Seed Balls - they're fun to make, they're easy to use, and they work better than a lot of other methods for establishing pollinator-friendly wildflowers in a garden. Try them out at your next gardening event!

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Bob Wildfong is Seeds of Diversity's executive director

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