Resourceful Gardening with Seed Bombs
Fresh seed bombs containing Hibiscus coccineus seeds
Seed bombs, also known as earth balls or seed balls, have roots in classical Egyptian agricultural practices. The method may have been widespread in the ancient world as an efficient way to sow large amounts of seed quickly, with minimal tools, especially after floods and other disruptions. Available sources indicate that some Native Americans used this method for sowing seeds. It is an effective way to sow seeds in areas with little rain.
A seed bomb is made with clay or paper, compost, and seeds. Some combination of seeds is wrapped in compost, and then covered with either clay, or papier-mache made with wet, shredded paper fibers. The balls are allowed to dry and harden before they are ‘deployed’ in areas where the seeds can grow without cultivation.
The humus or compost included in the seed ball supports early growth of the seed until it takes root in its environment. The covering protects the seeds from washing or blowing away, and from wildlife, until conditions are right for germination. This eliminates the need for tilling the soil before planting.
Gardeners, farmers, and restoration ecologists have employed this method of sowing seeds when the need was great and the resources, few. Seed balls were used in West Africa for rice cultivation. West African slaves imported this method for sowing rice to the Carolinas in the 18th Century.
Japanese agricultural scientist, farmer, and philosopher Masanobu Fukuoka made seed balls containing a variety of vegetable seeds to grow additional food in uncultivated spaces on his Japanese island home during and after the Second World War. Fukuoka experimented with ‘no-till’ farming methods during his career, and his methods discouraged use of fertilizers, herbicides, and pesticides. The organic gardening movement in the United States has roots in his work
More recently, seed bombs grew popular as part of the ‘Guerilla Gardening’ movement to beautify untended urban spaces and grow fresh food for people in cities. Guerilla Gardening became an international movement in the 1970s and continues as a grass roots effort to beautify public spaces, produce food for those in need, and to sequester carbon.
Seed balls, dropped from planes, were used in reforestation efforts in Haiti in the 1980s and in Kenya beginning in 2017. Millions of seed balls for reforestation have also been deployed in Kenya by means other than dropping them from the air, with significant success.
SeedBomb is an Irish company which makes and sells seed bombs with native wildflower seeds to preserve native species and support pollinators within Ireland. Maine has a Wild Seed Project to make and deploy seed bombs containing seeds of indigenous native species. You’ll find various pre-made seed bombs available through Etsy and Amazon.
Seed bombs can be tailored to many different purposes and environments. Whether they are made with native tree seeds, wildflower seeds, vegetable and herb seeds, or grain; seed bombs offer an efficient way to direct seed plants in challenging circumstances.
I researched several different methods for making seed bombs and settled on Crayola air dry natural white clay for its purity, low cost, and ease to use. Roll the clay out in a thin sheet. Cover it with a thin layer of screened compost or good topsoil. Avoid peat based commercial potting soil that contains perlite and added fertilizers.
Sprinkle a mix of seeds, or place the seeds individually, before cutting and rolling up small squares to form balls of about 1-1.5” in diameter. The number of seeds depends on their size and the spacing required for the plants. Be careful to use enough seeds to guarantee germination, but not so many that the plants will crowd each other.
If you use any seeds that require light for germination, press those into the outside of the ball. You can cover a clay ball with a layer of wet tissue paper for additional protection. Some makers use cayenne pepper in the coating to add a little extra protection.
Allow the seed bombs to completely dry before storing them or deploying them. This will take at least 24 hours, and possibly longer. Seed bombs may be packaged creatively, with instruction labels tied on, to use as gifts or favors.
Place seed balls somewhere you have confidence the species in the ball will grow successfully, shortly before a good rain. Rain (or watering) melts the clay and triggers germination. You can use them in an uncultivated place, in a pot of soil, or in a prepared garden bed. Guerilla gardeners might even throw the balls onto vacant land where they want to seed flowering plants. This is an effective method for reestablishing native species in a disturbed environment. Each seed ball can be partially buried, or just left on top of the soil, depending on the germination requirements of the seeds. Don’t ‘plant’ a seed ball completely in a hole because the seeds are already ‘planted’ in the ball.
This is a good activity to use with young people. You will find several lesson plans for making seed balls online, including ones associated with the Lady Bird Johnson Wildflower Center. If collecting seeds, take care to identify the plants and label the collected seeds correctly, and to avoid all invasive plants. Buying fresh, properly labeled seeds is the safest strategy, unless your purpose is to propagate indigenous native plants whose seeds may not be available for sale.
Should you want to experiment with seed balls, some of my first experimental batches will be available for visitors at the April 23 Arbor Day event at the Williamsburg Botanical Garden. They aren’t particularly pretty, but they contain seeds for native perennials including Echinacea, Hibiscus and Salvia.
If you take a few to try, plant them before the first of May for flowers this summer. I will be very interested to hear how they perform for you, and about your adventures with making seed bombs of your own.
Native Hibiscus coccineus
All photos by Elizabeth McCoy
Elizabeth McCoy is a JCCW Master Gardener Tree Steward and a Williamsburg Botanical Garden volunteer.