Is It Safe to Put Citrus in Compost? A Guide for Office Workers

If you compost at your office, you probably know the basics: Eggshells, apple cores, and veggie peels are safe to add to your compost bucket, but raw meat and produce stickers should be trashed. Easy, right? Well, maybe not — because it’s only a matter of time before you run into the “Can I put citrus in compost?” debate. 

An old gardening legend holds that adding too many highly-acidic citrus peels to your compost will prevent it from breaking down properly, or that the acid will kill off worms and beneficial microorganisms. 

We’ll dig into expert opinions on composting citrus in a moment. But first, we need to get one thing straight: Every compost system is different. 

Small-Scale vs. Large-Scale Composting

If you live in a city that composts on a commercial scale, like San Francisco, your office will be able to compost different things than a workplace relying on a small DIY compost pile. That’s because large-scale and small-scale compost systems work differently. 

In a commercial compost facility like Recology’s Blossom Valley Organics North, which handles San Francisco’s compost, workers carefully manage the compost piles. They add inputs like water and oxygen to bring the piles up to temperatures of more than 131 degrees F. This high-heat processing allows them to transform food scraps into compost in just 12 weeks. 

To see the process for yourself, check out the Recology video below. Their breakdown of the composting process starts at 1:42. 

Small-scale composting is different. Most people don’t want to spend time each week checking the temperature of their compost pile or installing pipes that will steadily circulate oxygen. Instead, they make simple backyard piles or use container units like worm bins that create compost more slowly and at lower temperatures than commercial composting. 

Why System Size Matters

The high heat created in commercial composting successfully breaks down materials that won’t decompose at home, like compostable takeout containers and other packaging. Commercial programs also often accept cooked meat, dairy scraps, and seafood remnants that aren’t recommended for home composters because they take too long to break down at a lower compost temperature, producing nasty smells and attracting pests. 

But what about citrus — can you compost that in both systems? 

The Truth About Citrus In Compost

The short answer to “Can I put citrus in compost?” is “Yes.” 

But there are a few nuances to consider depending on your compost system. Here’s a rundown of how to compost citrus in your office that covers commercial compost programs, worm bins, backyard piles, and even electric composters. 

Composting Citrus in a Commercial System

If your compost is destined for a commercial facility, you can add citrus peels and fruit to your bin to your heart’s content. 

Alexa Kielty, the residential zero waste senior coordinator for the San Francisco Environment Department, told The FruitGuys that citrus is “not at all a concern” for the city’s compost program.

She estimated that citrus waste makes up less than 1% of the approximately 600 tons of organic material the program collects each day. She also noted that a team of experts monitors the compost, adjusting its macronutrients to keep them at the ideal balance for each compost blend Recology produces.

“There’s a lot of custom blending that occurs at the end of the process to satisfy the needs of the individual customers, the farmers,” she said, noting that Recology may add supplements like calcium carbonate to the compost. “Depending on the agricultural product they’re growing, they’re going to need different NPK (nitrogen, potassium, and phosphorus) ratios.”

Composting Citrus in a Worm Bin

The Solana Center for Environmental Innovation in Encinitas, CA recommends composting citrus — and onions — sparingly if your office uses a worm bin. 

“The natural chemicals and acidity in citrus peels and onions can kill worms and other microorganisms, which can slow down decomposition rates in your bin,” the nonprofit wrote in 2021. “A well-maintained worm bin should have a pH measurement between 6.0 and 7.0, so it is best to play it safe and not include too many acidic foods.”

Composting Citrus in a Backyard Pile

If your office compost ends up in a backyard pile, some experts say that you can take the same relaxed approach as you would with commercial compost. Cary Oshins, the former associate director of the U.S. Composting Council, told the New York Times that his composting rule is “Don’t worry about it” — and that extends to citrus. 

The FruitGuys spoke to Maggie Marks, the director of Garden for the Environment in San Francisco, to get her take on the subject. 

Maggie is a longtime home composter and a graduate of Get Up!, an intensive three-month training program that qualified her to both teach composting and train other composting instructors. She said that citrus is safe to compost at home as long as you take proper precautions to prevent pests. 

“When you’re composting at home one of your biggest challenges is rodents, so any time you have an appealing food item in your compost bin that rodents might be attracted to, that’s something to consider,” she said. “[At Garden for the Environment], we recommend burying that food in the middle of your pile so it’s not somewhere that’s particularly tempting.”

If you’re worried that the citrus will decompose too slowly, you can cut or tear the peels into smaller pieces. 

“You’re actually trying to get as much bacteria and as many microorganisms into the food that you’re decomposing as possible. Ripping it up creates more surface area and rough places for bacteria and microorganisms to get in and start the decomposition process,” Maggie said. 

Finally, you should consider the amount of citrus waste you’re adding to the pile and whether you practice hot or cold composting. Hot home systems can handle larger amounts of citrus because their high temperatures break down waste faster. They naturally have fewer worms as well, so you don’t have to worry about the citrus oils harming them. If you compost in a cold system, you may want to compost citrus in small quantities to keep your pile’s worms healthy. 

Adding too much citrus can also throw off the balance of nutrients in your compost pile and produce an unpleasant smell. To counteract that, Maggie recommends experimenting with different carbon-rich inputs like dried leaves or sawdust. She added a few final words of wisdom:

“The most important thing for home composters to remember, especially new ones, is that this is a natural process. I find that very reassuring. This happens in nature, so it’s simpler than you think.”

Composting Citrus in an Electric Composter

If your office uses an electric composter like a Vitamix Foodcycler or Lomi, don’t rely on advice from the internet about citrus. Instead, go straight to your composter’s instruction manual or the manufacturer’s website for recommendations regarding putting citrus in compost. 

Vitamix, for example, includes “citrus fruit rinds” on its list of foods that users should avoid adding to their Foodcycler buckets in “high concentrations” along with rice, pasta, nut butters, and more. The instruction manual claims that “the dense, starchy and/or moisture-rich composition of these foods make them difficult to process in large quantities.” 

In other words, a few citrus peels are fine, but filling your Foodcycler bucket with citrus could cause mechanical problems. Look for similarly specific guidelines for your composter. 

More Green Ideas for Your Office

Composting food scraps like citrus is a great way to reduce your office’s carbon footprint, but you can make your workplace even greener by reducing food waste before it gets to the composter. For helpful tips, check out this guide: “4 Ways to Reduce Office Food Waste.”