Composting Watermelon Rinds

Watermelons are a delicious summer treat. But what do you do with all those leftover rinds? Don’t throw them away! Watermelon rinds are a fantastic addition to your compost pile.

Composting watermelon rinds is eco-friendly, reduces food waste, and provides valuable nutrients for your garden. This complete guide covers everything you need to know about composting watermelon rinds successfully.

Are watermelon rinds good for compost?

Watermelon rinds are good for composting. They are a valuable source of green matter for the compost bin, contributing nitrogen, nutrients, trace minerals such as phosphorous, and moisture, which are beneficial to the composting process. However, the rinds need to be chopped into smaller bits for them to compost completely and more quickly. 

Watermelon rinds are an excellent compost ingredient for several reasons:

  • They add nitrogen: Watermelon rinds provide a good dose of nitrogen, which is an essential nutrient for composting. Nitrogen helps fuel the microorganisms that break down organic matter.
  • They add moisture: Watermelon rinds are made up of over 90% water, adding valuable moisture to the compost pile. Proper moisture is necessary for the composting process.
  • They are high in fiber: All that watermelon rind fiber creates air pockets in the compost, improving aeration. Air circulation allows oxygen to reach the microbes hard at work decomposing the waste.
  • They are free and plentiful: Watermelons produce lots of extra rind material perfect for composting. Putting rinds to use reduces food waste.

Composting watermelon rinds is easy to do and has so many benefits for your garden! Keep reading to learn all the steps for successful watermelon rind composting.

Watermelon Rind Composting Basics

Before diving into the specific how-to steps, here are some key composting basics to understand:

1. Chop the rinds into smaller pieces

Large watermelon rind chunks can take a very long time to break down. Chopping the rinds into smaller 1-2 inch pieces provides more surface area for microbes to munch on.

Use a sharp knife or garden shears to cut up the rinds. You can also put small pieces through a food processor if you want a finer texture.

2. Bury the rinds under other compost materials

Watermelon rinds left exposed on top of a compost pile can attract pests like raccoons or rodents looking for an easy snack. Burying the chopped rinds a foot or so down in the compost prevents pest problems.

3. Maintain proper moisture and aeration

Watermelon rinds provide lots of innate moisture. But the overall compost pile still needs the right moisture content of around 50-60% to compost efficiently. Occasionally check the internal moisture level and water the pile if needed.

Turning and aerating the compost ensures oxygen circulates for a healthy microbial herd. Turn the pile 1-2 times per week.

4. Add a mix of green and brown compost materials

Shoot for a balance of wet, green materials (like watermelon rinds, fruit scraps and fresh grass clippings) and dry, brown materials (like leaves, straw and woody brush). Different materials provide carbon, nitrogen and other elements to create the ideal compost recipe.

5. Let it compost for 2-3 months

Compost happens fast when the right ingredients come together in the optimal conditions. Watermelon rinds and other soft, moist scraps compost more quickly than large branches or corn stalks. But allow at least 2-3 months for full decomposition into mature, usable compost.

Now let’s explore how to compost watermelon rinds using some specific composting methods.

Hot Composting Watermelon Rinds

Hot composting uses a special process to speed up decomposition. The compost pile heats up naturally, which accelerates the work of heat-loving bacteria. Hot compost can finish in as little as 4-6 weeks!

Hot composting works well for watermelon rinds. Here is a simple hot compost recipe using rinds:


  • 5-10 lbs chopped watermelon rinds
  • 1 lb fresh grass clippings
  • 1 lb coffee grounds
  • 1 lb green plant leaves or trimmings
  • 5 lbs straw or wood shavings
  • Compost starter (optional)


  1. Prepare a compost bin at least 3ft x 3ft wide and tall. Wood pallets or wire fencing work well to contain the pile.
  2. Add the straw or wood shavings as a base layer for aeration.
  3. Mix in the watermelon rinds, grass clippings, coffee grounds and plant clippings on top.
  4. Sprinkle compost starter (contains bacteria and enzymes to jumpstart decomposition).
  5. Keep compost moist like a wrung-out sponge, watering as needed.
  6. Turn and mix the pile with a pitchfork after 3 days, then twice a week after that.
  7. When the internal temperature reaches 140-160°F, the compost is “cooking.”
  8. Once temperature starts dropping after a few weeks, the compost should be ready for harvesting.

Hot composting does require more effort with frequent turning and monitoring. But you’ll be rewarded with faster finished compost full of nutrients thanks to those watermelon rinds!

Cold Composting Watermelon Rinds

Cold composting is a slower, more passive approach. You simply combine compost materials in a pile or bin and let nature run its course. This low-maintenance method works for any schedule.

Here’s a simple cold compost recipe using watermelon rinds:


  • 5 lbs chopped watermelon rinds
  • 2 lbs coffee grounds
  • 1 lb fruit and vegetable scraps
  • 10 lbs “browns” like dried leaves, straw, wood chips


  1. Prepare compost bin or pile in your preferred style and location.
  2. Spread brown base materials for aeration.
  3. Layer greens and browns, burying fruit and veggie scraps under layers.
  4. Mix in watermelon rinds as you add layers.
  5. Water occasionally if pile seems dry.
  6. Turn or mix pile 1-2 times per month with pitchfork or compost aerator.
  7. Let compost slowly break down over 2-4 months until ready to use.

The hands-off approach makes cold composting super simple. Just pile up the scraps, let the microbes work their magic, and you’ll have rich, nutritious compost.

Compost Tumblers – Fast & Contained

Compost tumblers provide an efficient system for composting kitchen scraps like watermelon rinds. The enclosed drum design keeps pests out. Giving the drum a spin mixes and aerates the compost for faster finishing times.

Compost tumblers come in a variety of shapes and sizes. For watermelon rinds, look for a model with at least a 60 gallon capacity. Popular rotating drum tumblers from companies like Miracle-Gro or FCMP Outdoor make composting simple and fast.

Follow these tips for great results composting watermelon rinds in a tumbler:

  • Chop rinds into 1 inch pieces to break down quickly.
  • Add an equal amount of brown materials like dry leaves or newspaper.
  • Keep compost moist but not saturated by occasionally spraying water.
  • Rotate drum 3-4 times per week to aerate.
  • Fill drum fully for best compaction and decomposition.
  • Harvest finished compost in as little as 3-4 weeks!

Compost tumblers provide efficient, pest-free composting with little effort required. Their speed and convenience make them ideal for watermelon rind recycling.

Vermicomposting Watermelon Rinds

Vermicomposting uses worms to break down organic waste. Red wigglers are the composting worms of choice since they munch through scraps rapidly. Providing the right bedding and moisture keeps the worms happy and hungry.

Vermicomposting watermelon rinds in an indoor worm bin is easy:


  • Chopped watermelon rinds
  • Worm bedding like shredded cardboard, coconut coir or straw
  • Handful of red wiggler worms
  • Water as needed for moisture


  1. Prepare bin with bedding for worms, providing airflow and darkness.
  2. Bury watermelon pieces under bedding so worms can find them.
  3. Add a handful of red wiggler worms from bait shop or garden store.
  4. Feed worms watermelon rinds and other fruit/veggie scraps.
  5. Keep bedding moist but not soaked.
  6. Harvest vermicompost as it accumulates in bin.

The worms will devour those watermelon rinds quickly while producing “black gold” worm compost. Vermicompost provides an extra nutrition boost for potted plants and seedlings.

Troubleshooting Watermelon Rind Composting

Composting watermelon rinds is generally easy, but a few issues can pop up:

Problem: Rinds are decomposing too slowly

Solution: Chop rinds into smaller pieces for faster composting. Turn and mix the pile regularly to speed things up.

Problem: Bad odors coming from the compost

Solution: Add more brown materials like leaves or sawdust to improve aeration. Turn the pile to release trapped gases. Reduce watering if pile is too wet.

Problem: Mold growing on rinds

Solution: Bury rinds deeper under other compost. Improve air circulation by turning pile. Add more dry browns to absorb excess moisture.

Problem: Pests snacking on the rinds

Solution: Prevent pests by fully burying rinds inside the compost so they aren’t exposed. Use enclosed compost bins.

Follow the steps in this guide and you’ll avoid most problems composting watermelon rinds. Reach out to local agricultural extension offices for extra advice if needed.

Using Finished Watermelon Rind Compost

After a few months of decomposing, your pile of waste will transform into dark, crumbly, sweet-smelling compost.

Watermelon rinds create very nutrient-rich compost. Those nitrogen-boosting rinds yield compost higher in nitrogen compared to traditional mixes.

Here are some of the great ways to use your finished watermelon rind compost:

  • Mix into garden beds & flower pots: Blend 1-2 inches of compost into soil to provide nutrients for vegetables, herbs, flowers and more.
  • Top dress lawns: Spread 1/4 inch layer of compost over grass to fertilize naturally and improve drainage.
  • Mulch around trees & shrubs: Place 2-3 inch compost layer around plant root zones to retain moisture and suppress weeds.
  • Make compost tea: Steep compost in water to extract microbe-rich tea for watering plants. Great foliar fertilizer!
  • Potting soil amendment: Add 20% compost to any potting mix to improve fertility and moisture retention for container plants.

Don’t let those big piles of watermelon rinds go to waste! Put them to use in your compost and enjoy their benefits in your garden all season long.

Alternative Uses for Watermelon Rinds

Besides composting, what else can you do with watermelon rinds? Here are some other eco-friendly uses for these scraps rather than tossing them in the trash:

  • Feed watermelon rinds to livestock like pigs, goats or chickens as a nutritious treat
  • Dehydrate or pickle rind slices for unusual snacks or garnishes
  • Use rinds as a natural hydrating face mask or skin soother
  • Ferment the rinds into probiotic-rich pickled watermelon rind relish
  • Boil rinds on the stove and strain to make refreshing watermelon rind tea
  • Puree or blend rinds into a thickener for smoothies, popsicles or other drinks
  • Candy the rinds by boiling in sugar syrup for a sweet dish with a twist

With a little creativity, you can transform watermelon rinds into tasty culinary creations instead of compost. But recycling them in your compost pile is still one of the easiest and most beneficial ways to put this waste to work.

The Joys and Benefits of Composting Watermelon Rinds

What could be better than turning summer’s juicy watermelon harvest into a bounty for your garden? Composting those plentiful rinds provides free “black gold” to give back to your plants and soil.

Here’s a recap of the many joys and benefits of composting watermelon rinds:

  • Reduces kitchen waste destined for landfills
  • Provides key compost ingredients like moisture, nitrogen and biomass
  • Creates incredibly nutrient-rich compost for your garden
  • Saves money on buying fertilizers or soil amendments
  • Helps gardens, lawns, trees and plants grow bigger and stronger
  • Improves overall soil structure and water retention
  • Closes the loop from scraps to nourishment in an eco-friendly cycle
  • Gives you free, homemade “super compost” from a common waste item

Let those lovely watermelons keep on giving even after the tasty flesh is gone. Embrace composting as the sustainable and satisfying way to handle watermelon rinds!

Frequently Asked Questions

Q: Do you need to remove the outer green rind from watermelons before composting?

A: The entire watermelon rind can be composted, including the outer green rind. No need to peel it off!

Q: Can you put whole watermelon rinds in compost or do they have to be chopped up first?

A: Chopping rinds into smaller 1-2 inch pieces allows them to break down much faster. Whole rinds will take a very long time to decompose.

Q: How much watermelon rind can you add to a compost pile?

A: Watermelon rinds can make up about 25-50% of total compost volume. Any more may disrupt the right carbon-nitrogen ratio.

Q: Should watermelon rinds be avoided in indoor worm composting bins?

A: Watermelon rinds are fine for vermicomposting! Just bury them under bedding and monitor moisture levels. The worms thrive on watermelon.

Q: Can you put diseased watermelon rinds in compost piles?

A: Avoid adding any diseased plant material to compost, as it may spread disease back to your garden. Only compost healthy rinds.

Composting watermelon rinds is easy, eco-friendly, and hugely beneficial for your garden! Follow this guide and see just how valuable those scraps can be. Let your compost unlock all the nutrients and goodness from your leftover watermelon rinds.