Want to fertilize your garden with giraffe dung? This Seattle zoo is giving you the chance

Fertilizer can be made from nearly any natural waste: fallen leaves, kitchen scraps, weeds, coffee grounds, crops… and even zoo animal manure.

The Woodland Park Zoo in Seattle is really leaning into the last item on that list. On Oct. 15, the zoo will be distributing approximately 500 tons of fertilizer created from animal poop to customers who purchased it online in advance.

Dubbed the Zoo Doo program, Woodland Park Zoo collected the waste from its non-primate herbivorous animals — rhinos, giraffes, hippos and zebras, among others — over the course of the year and stored it in the “Zoo Doo yard” to begin the process of composting.

“The compost gets used on-site by our horticultural teams, as well as in the annual exhibits,” said Liv Johansson, sustainable waste management specialist for Woodland Park Zoo in an interview with McClatchy on Friday. “It gets donated to local community gardens, school gardens, food banks, and it gets sold to the broader communities.”

With the composting process now complete, Washington residents can purchase bulk quantities of fertilizer online before picking up their order on Oct. 15.

How is animal dung turned into fertilizer?

Plants need a lot of energy to successfully flower and grow, and fertilizer provides a healthy supply of vital nutrients into the soil, helping plants grow faster and larger.

Manure is an excellent fertilizer because it contains nutrients like nitrogen and phosphorus, according to the U.S. Environmental Protection Agency, which are critical nutrients for plants to grow.

Woodland Park Zoo collects manure from its herbivorous animals over the course of the year and stores it for 30 days between 135 and 160 Fahrenheit, which the zoo claims on its website is the optimal temperature for decomposition.

Once the active decomposition phase has finished, the temperature decreases, and the manure is left to sit for another 30 days. During this period, microbes break down materials in the dung, such as weed seeds and potential pathogens.

The process the zoo uses is called capped aerated static pile composting, Johansson said, where the manure is bedded with straw and wood chipping, sprayed with water, and then covered tightly with a tarp and aerated from below by air ducts.

At the end of the process, the compost will look dark and crumby, resembling actual soil much more than its original form of animal dung. At this point, it can be considered fertilizer and is officially ready for use.

How much does zoo animal fertilizer cost?

Woodland Park Zoo sells its dung in bulk quantities. The seven available pickup sizes and their prices are as follows:

• 25-gallons - $15

• 50-gallons - $30

• 70-gallons - $40

• 100-gallons - $50

• 300-gallons - $80

• 400-gallons - $100

• 550-gallons - $120

You can pre-order fertilizer online on Woodland Park Zoo’s website and receive directions on when and where to pick up your fertilizer.

“Folks sign up and prepay online, and then they come with their trucks or they come with buckets, they fill up their trucks and buckets themselves by hand,” Johansson said. “And then they take it home and garden with it. So that’s our sales model; we like to bring the community in to help do it themselves.”

Johansson also noted that this will be the zoo’s final Zoo Doo until early April 2023.