The Ultimate Guide to Reusing Kitchen Scraps & Leftovers to Reduce Food Waste
The Ultimate Guide to Reusing Kitchen Scraps & Leftovers to Reduce Food Waste

From veggie peels to what’s left of yesterday’s roast chicken, it’s easy to toss seemingly unusable leftovers in the trash without a second thought. But what if there’s more to these kitchen scraps than meets the eye?

Although food waste is a worldwide challenge, there are lots of little ways we can make a big difference at home. From regrowing your favourite vegetables to freezing avocados (it’s true!), here are 5 ways you can get creative with kitchen scraps and leftovers to reduce food waste, save on your grocery bill, and do a solid for the environment.

Regrow Vegetables from Roots & Stems

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With a little sunshine and some water, many of your favourite vegetables can be regrown into a whole new plant — no backyard garden necessary. Flex your green thumb with these easy-to-grow windowsill vegetable projects, fun for kids and adults alike!

Green Onions

Probably the easiest and most rewarding veggie to regrow on the list, fast-growing green onions (also known as scallions) only need a glass of water and a sunny windowsill to flourish into a beautiful, brand new plant.

How to grow green onions in water:

  • When you’re chopping up your green onion for a recipe, save about an inch up from the roots.
  • Place in a glass in a well-lit spot, root end down, covering the roots with water and leaving the top edge exposed.
  • Change the water every few days and watch your scallion sprout!


Lettuce & Bok Choy

Enjoyed a salad with simple homemade dressing for dinner? Before you toss that lettuce nub in the compost bin, regrow it into a brand new batch of lettuce leaves — perfect for a side salad or sandwich topper. This technique works best with romaine lettuce, but other leafy greens like cabbage and bok choy will sprout too.

How to grow lettuce in water:

  • When you’re preparing your lettuce, save about an inch up from the stem.
  • In a well-lit spot, place the stem in a shallow jar and cover about halfway with water.
  • Change the water every other day until new leaves sprout and roots appear.
  • After about a week and a half, harvest your new batch of lettuce.



Almost as easy to grow as green onions, herbs like basil, mint, and thyme can be easily regrown in a simple glass of water. Keeping the water fresh and the leaves pruned will help them last quite a while on a windowsill.

How to grow herbs in water:

  • Save a sprig of your favourite herb, clearing the leaves from the bottom two-thirds of the stem but keeping the top leaves intact.
  • Snip a bit off the stem, cutting at an angle to help it absorb more water.
  • Place in a glass of water, making sure no leaves are submerged. Set in a sunny spot.
  • Change the water every few days and watch your herbs sprout!

Chef’s Tip: Once roots take form, you can plant your projects in a pot or backyard garden.


Make Broths & Soups from Leftovers

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Avoiding food waste starts with ‘shopping smart’: planning your weekly meals, making a grocery list and sticking to it, and only buying what you need. Even so, you’re bound to end up with a few leftovers now and again. So what can you do with the roast chicken, mashed potatoes, or excess pasta from last night? Make broths and soups!

Vegetable Broth

Flavour-packed veggie broth is not only easy to make, it also helps you get more out of your produce and save on store-bought broths. You can use whatever vegetable scraps you have on hand like onion and garlic ends, carrot peels, celery stalks and leaves, fresh herb stems, ginger nubs, and wilted greens that didn’t make it to the salad bowl in time.

Some chefs suggest avoiding cruciferous veggies like broccoli and Brussels sprouts, while others encourage using them in moderation. Test it out for yourself and see what flavour profiles work best for your broth.

How to make vegetable broth:

  • Before prepping, wash vegetables to remove any dirt or debris. Discard any moldy items in the compost bin.
  • While preparing your mise en place for a meal, save vegetable scraps like peels, stalks, stems, and leaves in a freezer bag and freeze until the bag is full.
  • When you’re ready to make your broth, empty the bag into a large pot. Add enough water to generously cover the scraps.
  • Season with salt and pepper and any other favourite seasonings, to taste.
  • Bring to a boil then reduce heat and simmer for about an hour.
  • Remove from heat. Using a strainer set over a large bowl, strain out the vegetable scraps. Taste the broth and season as needed. You may want to use a fine-mesh strainer to strain the broth again.
  • Discard any scraps in the compost bin and let the broth cool.
  • Portion, label, date, and freeze to use later as a base for soups, stews, and sauces.


Chicken & Bone Broth

After a delightful chicken dinner, turkey feast, or other meaty meal, save the leftover bones for a delicious homemade broth. Cooking down bones for broth is a little more labour-intensive than making vegetable broth, but it’s well worth it for the rich, savoury flavour your broth will bring to future meals.

How to make chicken (or bone) broth:

  • Remove any remaining meat from the bones and save for a future soup or sandwich.
  • Place bones in a large pot and generously cover with water. Add a splash of apple cider vinegar or lemon juice to help break down the collagen in the bones.
  • Season with salt and pepper and other seasonings, to taste.
  • Bring to a boil, then lower the heat and simmer for 12 hours or more. The longer it reduces, the more intense the flavour.
  • You’ll notice foamy residue rising to the top as the broth cooks down. Every once and a while for the first few hours, skim away the foam and discard.
  • About 6 hours before the broth is done, add vegetable scraps like onion, carrot, celery, garlic, and herbs to the pot. You can add a bit more water if needed.
  • Remove from heat and allow to cool slightly. Using a fine-mesh strainer set over a large bowl, strain out the bones and vegetable scraps. Discard the bones and scraps and let the broth cool.
  • Portion, label, date, and freeze to use later as a base for soups, stews, and sauces.


Make a Soup Out of That

From appetizers to main courses, side dishes to sauces, soups can make new meals out of last night’s leftovers and the veggies at the back of the crisper drawer. It’s one of the quickest, easiest, and most delicious ways to use up items in your fridge and pantry!

How to make soup from leftovers:

  • In a large pot on medium heat, drizzle a bit of oil and add chopped vegetables like onions, celery, and carrots (known as mirepoix). Season with salt, pepper, and your favourite seasonings, tasting and adjusting throughout the process.
  • Add in a bagful of your homemade broth (thawed or from frozen) and bring to a boil.
  • For a thicker soup, you can add in leftover gravy, mashed potatoes, pasta sauce, cheese sauce, or cornstarch slurry.
  • Reduce heat and simmer, adding in already cooked leftovers like meats, roasted veggies, and pasta or grains.
  • Optional: Blend for a smooth, creamy soup.

Chef’s Tip: Freeze broths and soups in medium-sized freezer bags, laid flat to save room when frozen.


Freeze Foods You Didn’t Know You Could Freeze

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Freezing food is a great way to prolong shelf life and keep ingredients on hand for later use. Be strategic about what you freeze and how you freeze it — you don’t want to end up with a freezer full of items you’re just prolonging throwing out (we’re looking at you, frozen bananas for ‘banana bread’!). Using your freezer space strategically and incorporating what you’ve frozen into your weekly meal planning can help reduce food waste.

While some freezer-friendly foods are well known, like the aforementioned banana, other freezable foods might surprise you!


The notorious avocado — not ready, not ready, not ready, ripe, too late! If your avocado is ripe but you’re not ready to use it, pop it in the freezer whole. Yup, just like that. When you’re ready to use it, take it out of the freezer and run it under hot water for a minute or two. Let it thaw on the counter for about half an hour until it starts to feel soft, then slice and peel off the skin. Your avocado is good as new and ready to use in guacs, on sandwiches, and more!

Fresh Herbs

We’ve all bought a bunch of fresh herbs with good intentions. After a sprinkle here and a garnish there, the herbs are left to fend for themselves at the back of the crisper drawer. Fresh herbs can last pretty long in the fridge under the right conditions, but give yourself even more opportunities to use them in your home-cooking by freezing them.

When your herbs start to get a little wilty, roughly chop and place in an ice cube tray. Top with olive oil, adding just enough to cover the herbs. Freeze overnight and then store in a freezer bag or container. When you want to add a taste of fresh herbs to a cooked meal, add a cube to a hot pan and use like you would regular cooking oil.

Eggs (No Shell)

The rumours are true: you can freeze eggs! While frozen eggs don’t work the same as fresh eggs in all recipes, they’re still great to use in scrambled eggs, omelettes, and a lot of baked goods.

If you have a few stragglers left in your egg carton, you can freeze them until you’re ready to get cooking. Simply crack an egg into a large ice cube tray or whisk eggs together in a bowl, evenly portion in an ice cube tray, and freeze. When you need an egg, thaw in the fridge overnight and use right away. Note that this trick only works for raw eggs, hard-boiled eggs do not freeze well.

Chef’s Tip: Not sure if your eggs are fresh enough to freeze? Place your egg in a glass of water. If the egg remains at the bottom on its side, it’s still fresh. If it stands on its end, it’s still good but the clock is ticking! If it floats, it’s time to toss it.


Fresh Pasta

Fresh pasta elevates just about every pasta dish and cooks in half the time (or less) than its dried counterpart. The nature of the ingredients means fresh pasta has a fairly short shelf life and may become clumpy and lose its freshness after a few days in the fridge.

To preserve the magic that is fresh pasta, use your hands to separate any strands that may have stuck together, portion, and pop in the freezer in a freezer bag or container. You can cook straight from frozen, as cooking time will only take an extra minute or two longer.

Hummus, Pestos & Sauces

Made a big batch of that pasta sauce, tried a new type of pesto, or bought three types of hummus because you couldn’t choose a flavour? Portion into smaller, manageable batches and freeze in freezer bags or containers. Once you’re ready for more, pull one from the freezer and give it a day to thaw in the fridge. When thawed, give it a good stir and use as you normally would.

Tomato Paste

Many times, a recipe calls for only a tablespoon or two of tomato paste. What’s a home cook to do with the rest of the can? You don’t want to let all that condensed tomatoey goodness go to waste, after all.

To prepare for future use, add tablespoons of tomato paste on a baking sheet lined with wax paper or plastic wrap and place in the freezer. Once frozen, store the portioned paste in a freezer bag or container. Next time a recipe calls for a tablespoon of tomato paste, you’ll be ready and waste-free!


Before that forgotten half-block of cheddar grows a little peach fuzz, pop it in the freezer! Although cheese connoisseurs don’t recommend freezing cheese because of the resulting taste and texture changes, packaged cheese tends to hold up pretty well in the freezer (not so much for soft cheeses like brie or artisanal cheeses).

You can throw a whole unopened package like mozzarella, swiss, or cheddar cheese right in the freezer. You can also freeze grated cheese to have on hand for pizzas and other recipes.

Chef’s Tip: When freezing food, don’t forget to clearly label your bags or containers with the name of the item and the date you froze it. Keep an inventory and use the oldest stuff first so nothing is wasted.


Offer a New Life to Loaf Ends

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No one particularly likes the end of the bread loaf, but save it from the bin and transform it into something brand new. You’ll be amazed to see these stale, crusty ends shining in a whole new light.


Do-it-yourself croutons are super easy to bake and make delicious additions to a salad or on a soup. You can use any type of bread, cook them to your desired level of crunchiness, and customize them with whatever herbs and spice you like.

How to make croutons:

  • Slice and dice your bread into cube shapes of about the same size.
  • In a large bowl, toss the bread with a generous drizzle of olive oil, salt and pepper, and the seasoning of your choice, to taste. Toss until evenly coated.
  • Spread out the croutons-to-be on a lined baking sheet and bake at 350ºC until crispy, turning halfway through.
  • Once cooled, store in an air-tight container for up to 2 weeks.



Like croutons, you can use any kind of bread to make breadcrumbs. Staler bread works better since it has less moisture and will grind smoothly without clumping. Use breadcrumbs as a coating for fried meats and vegetables, on top of casseroles, or in meatloaf.

How to make breadcrumbs:

  • Roughly dice your bread into cubes and add to a food processor or blender. Pulse until you reach your desired crumb size.
  • On a lined baking sheet, spread the crumbs in a single, even layer and bake at 300ºF for about 10 minutes, stirring halfway through, until lightly toasted and dry to the touch (be careful, they’re hot!).
  • Once cooled, store in an air-tight container for up to 2 weeks.

Chef’s Tip: Save up your loaf ends, extra buns, and crusts for a few days, as both croutons and breadcrumbs work better with staler, drier bread.


Compost the Rest

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Taking steps to reduce food waste and keep organic household waste out of the landfill is possible by reducing, reusing, and recycling what we can. If we can’t reuse or recycle an item, the last step on the list is to compost it.

Composting gives food waste a second life by feeding nutrients back into the soil, reducing the need for chemical fertilizers, and lowering methane emissions coming from landfills.

Luckily, composting has never been easier, even in an apartment! Many cities now have curbside compost collection and all you need to participate is a countertop compost bin or freezer bag to collect your kitchen scraps until pickup day.

To begin your composting journey, start monitoring what you throw away and compare with your municipality’s list of compostable items. What’s allowed in your compost bin varies from city to city, so check the guidelines to see what’s accepted in your area.

Here are some commonly accepted items:

  • Fruits and vegetables
  • Herbs and spices
  • Bread, rice, pasta, cereal, pastries
  • Eggs and shells
  • Coffee grounds and tea leaves
  • Nuts and shells
  • Soiled napkins, paper, and cardboard
  • Meat, poultry, bones, fish, seafood (sometimes)
  • Solid dairy products (sometimes)

Imagine the compost you contributed to grew the purple asparagus you cooked the other night, whose stalks made a veggie broth you used to make a soup you served with roast chicken whose bones you made another broth out of before composting which helped grow… *cue The Circle of Life*

Although it may feel like an overwhelming task to tackle, every act, no matter how small it may feel, helps reduce food waste and the amount of organic material ending up in landfills.

Always remember to practice food safety first. If something is no longer safe to eat or is growing a fuzzy new coat, it’s time to toss that bad boy in the compost bin.

Image Credits

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