Things you might not think about
In order to maximize the effectiveness of your efforts and also prevent inadvertent damage to the environment, there are some steps to planning a seed bombing campaign that should be undertaken diligently.
Seek out a location that is in need of native vegetation. Make certain that the location is abandoned, and does not have restrictive signage, fences, or other indications that your presence and efforts are not welcome. There are plenty of places to improve biodiversity legally, so there is no need to break the law. In fact, you might consider knocking on some doors. Many landowners will welcome native wildflowers and will happily grant you access to their land for this purpose.
Once you have identified a suitable location, it is time to do some deeper investigations to characterize capacity of the location to support plant life.
In order to select suitable species of plants, you should learn about the soils and climate at the site. The USDA Web Soil Survey is a great free resource to learn about the soil at your selected site through an interactive map tool. Using the Web plants.usda.gov
Soil Survey, you can find the name of the Soil Series at your location. You can then reference the Soil Series name in the USDA-NRCS Soil Series Description listings. The descriptions detail the different layers of soil that you will find in that area. If your site is heavily disturbed, your soil will most likely resemble what is called the B-horizons of the soil. The most critical factors are the soil organic matter content, texture, and the soil moisture regime, which are frequently referenced on seed packets and published information about plant requirements.
By learning more about the soils at your location, you will come to understand the conditions that your seed bombs will be facing once you abandon them to the winds of fate.
Species of Plants
You’ll want to use US native plant species that are local to your area. This is important. Anything else and you are not contributing to the conservation of the site. Take a look at the Biota of North America Program‘s maps and find some species that will work well in your region and are native to it. The USDA-NRCS Plant Database will tell you about the requirements and conservation status of the species that you are interested in. You will be surprised at how many US native wildflowers in your area are endangered and how easy it is to help those species along!
You will want to gather seeds by harvesting with an understanding of local botany and respecting local laws. To ensure that you have the correct seeds, look for a company that is in North America where the native species grow. Some over seas companies use any old seeds and label them to fit your order. This is dangerous and could result in the spreading of invasive species. Many seeds look similar, so it is important that you are confident in the identification of the species. If you have questions, the supplier should be able to answer them and give authoritative assurance that the seeds are authentic. It is important not to over-load the seeds within each seed bomb. Between one and three seeds per seed ball is usually sufficient.
The Seed Bombs
There are several types of pre-made seed bombs to choose from and even more recipes. For conservation work you will not want to use seed bombs that come packed with loads of mixed seeds of multiple species in every seed bomb. The high density of germinating seeds will stress seedlings and the strongest germinating species will likely survive in each case. It is best to either purchase seed balls containing individual native species, or make your own.
Making your own is quite rewarding. You can use a pre-made seed ball mix or follow a recipe. Pick a recipe that has an abundance of organic matter and readily obtainable supplies.
Timing the Seed Bomb Campaign
The season that you sow the seed bombs can have a significant impact on your success. The required timing will depend upon the species that you are sowing.
Some seeds (and therefore seed bombs) require fall planting or stratification to trigger germination. You can fall plant seed bombs that need stratification even in the winter, just poke them through any snow cover so they have contact with the ground. Make certain that you give them enough time in the cold to trigger germination. Other seeds are frost-tender and you will want to wait until after frost to sow the seed bomb.
The right season for planting depends upon the species. Do your homework and understand the plant’s requirements and sow accordingly.
Have fun and be safe, especially if you are seed bombing near roadways.