According to the USDA, as much as 40% of our food supply ends up in the trash or compost bin—that's an average of 219 pounds per person annually. And more than one-third of that stems from wasteful kitchen habits. Food waste, like broccoli stems and moldy cheeses, takes up more space than any other form of garbage in landfills, where it emits methane and other greenhouse gases that contribute to climate change. Then there's all the plastic used to package and transport that wasted food, not to mention the land, water, energy and other resources it takes to produce it.

But here's the upshot: You can make a meaningful change by adopting some new habits in the kitchen. By reducing U.S. household food waste by just 20%, we could cut annual greenhouse gas emissions by an estimated 6 million tons annually. That's the equivalent of taking almost 1.2 million cars off the road for a year.

Your pocketbook could also benefit from reducing waste, to the tune of $1,300 a year. That's the average amount each American spends on food that ends up in the trash. We purchase more than we need, discard items we think are spoiled due to misleading packaging dates, and we regularly throw out leftovers.

Ready to do something about it? Let's get started!

Avocados and other fruits that are usually purchased before they're ripe (think pears, kiwi, mangoes, melons, peaches) should be stored at room temperature until they reach peak deliciousness. Then, if you find yourself with more than you can eat before they'll turn to mush, pop them in the fridge where they'll keep for a week or more. To keep leftover avocado halves or quarters from browning, add a splash of citrus juice or a drizzle of olive or vegetable oil (the oil serves as a barrier against oxygen) to the exposed fruit. And keep those pits in place, if you can, they help keep the flesh greener longer. Later, use the pit to grow your own avocados!

Related: How to Store Avocados So They Last

Banana-Chocolate Chip Snack Cake is just the thing to make when you're faced with a bunch that's about to go bad. Bananas may also be frozen for use later in smoothies or in your favorite baked goods.

Composting is the answer to the bits and bobs left over from meal prep (let's be honest, some food waste is simply unavoidable). Not only does it significantly reduce the amount of methane released into the atmosphere from landfills, the end product helps improve soil health. Many communities now mandate composting, so check to see if your area has a designated drop-off spot or pickup service. Or you can get a compost bin for your yard. Keep a bucket with an odor-eliminating charcoal filter in your kitchen to collect food scraps until you're ready to take them out. What can be composted varies depending on the method, but fruit and vegetable scraps, egg shells, tea leaves and coffee grounds are typically fair game. (Some backyard bins and commercial operations can handle meat and compostable packaging as well.)

Related: Composting 101: How to Compost at Home

Dairy products rival vegetables as the most-wasted food category in U.S. households. Instead of automatically dumping your dairy when the "use by" date passes, give it a sniff. If it smells OK and there's nothing fuzzy growing on it, use it up fast. Most dairy products also freeze well. Shred hard cheese first. Portion yogurt, milk and even whipped cream in ice cube trays so they'll be easy to incorporate into smoothies, top hot cocoa with and more.

Related: Freezing Milk Makes It Easy to Stock Up and Save

Ethylene is a natural gas that's released from some fruits and vegetables and speeds up the ripening process. That can be an advantage—to soften an avocado more quickly, you can seal it in a paper bag to trap that gas—but too much ethylene makes produce spoil. To lengthen shelf life, store fruits and veggies that release high amounts of the gas (stone fruit, ripe bananas, tomatoes) separately from ethylene-sensitive produce (onions, potatoes, squash). In general, this means separating fruits from veggies, with a few exceptions.

Freezing is one way to reduce food waste at home. Many foods can be stashed in the freezer to preserve freshness for three months or more. But unless you actually eat what you freeze, it can also be where food goes to get freezer burn and die. Keep a running list of what's in there and the date you froze it on a dry-erase board or piece of paper, or make an electronic list. In addition, simply labeling every item that goes in the deep freeze with the date it was frozen is useful. Check your list when planning meals to ensure you use frozen foods before their quality diminishes.

Related: 8 Foods You Should Never Freeze

Grounds from your morning cup of joe can be repurposed. Add a scoop to brownies and chocolate cake to boost the chocolaty-ness. Gardeners can till grounds into the soil, where they'll attract earthworms that will aerate the soil. Or, get one more use out of them and make Spent Coffee Grounds Ice Cream. While we're on the topic, it's time to ditch the single-use coffee pods—there are tens of billions of those in landfills already. Instead, invest in a reusable coffee filter.

Kitchen cleanup can produces a lot of waste. Single-use towels are a big chunk of the 12% of U.S. landfill space that's taken up by paper products. Make the switch to reusable "un-paper" towels, usually made from cotton, bamboo or sugar cane. Just rinse, twist out excess water and toss them in the wash (some need to be washed by hand). If you can't commit, remember you can compost paper towels and some parchment paper (as long as it hasn't been used with anything that's not edible).

Related: These Compostable Sponge Cloths Are Perfect for Cleaning

Leftovers—whether cooked or simply what remains from a package of carrots or mushrooms—can be more appealing when you make a plan to use them. Work a "fridge sweep" meal, like fried rice, quiche or Use-It-Up Vegetable Soup, into your menu each week.

Mustard, mayo or hot sauce containers with just a swipe or two left are perfect for making instant flavor-packed vinaigrettes. Before you rinse and recycle them, add vinegar, oil and herbs, screw on the lid and shake.

Related: How to Make Perfect Homemade Vinaigrette Every Time

Noodles of varying shapes, sizes and amounts are likely hanging out in your pantry. Toss them into soups or make a meal for one or two. Combine similar shapes with the same cooking time—does it matter if they match when you're eating dinner?

Related: Easy Skillet Tuna Noodle Casserole

Organize your fridge and pantry by the "first in, first out" mantra. Put the oldest foods in front where you'll be more likely to see and grab them before they spoil, and place newer ones toward the back. The same goes for shelf-stable items. If your family needs a little—ahem—help with this idea, try consolidating eat-now foods into a labeled "use first" area.

Related: 10 Rules to Organize Your Refrigerator the Right Way

Infused salts have fancy vibes and are easy to make on your own. Blitz coarse sea salt with celery leaves, citrus zest, coffee grounds, herbs, edible flowers, chiles or grated ginger or garlic in a clean spice grinder. Transfer to a bowl and let stand, uncovered, for 3 days. Store airtight and sprinkle on just about anything (your popcorn will never be the same!). They make a great gift too.

Related: How to Make the Most Delicious Popcorn at Home

Pickle, olive and feta brine left from a jar or tub is liquid gold. Use it to make Any-Brine Chicken with Herb Pan Sauce.

Quantity buys may seem like a good deal. But unless you're going to eat that ginormous box of salad greens, baby cucumbers or cherry tomatoes within a few days, it's just wasting money and food. Pick up perishable foods in amounts you'll be able to realistically use, and go for bulk on shelf-stable stuff like toilet paper and olive oil.

Related: 10 Best Weight-Loss Foods to Buy at Costco, According to a Dietitian

Reusable containers can help reduce plastic waste. Tuck a few in your shopping bags and bring them to the butcher and deli counter—most staff will be happy to use them. And if you shop at a store with bulk bins, bring those containers for staples like grains, cereals, beans, spices, nut butters, coffee and oil. Be sure to weigh each empty container with its lid and mark its tare weight before you fill, so it can be deducted at checkout.

Related: Best Food-Storage Container Ideas to Break Your Plastic Habit

Salad greens are one of the most perishable foods we buy—going from fresh and perky to slime in what seems like an instant. Before they rot, bake a batch of Wilted Greens Dog Treats. They're Fido-approved!

Trimmings like cabbage and cauliflower cores and broccoli stems tend to get discarded, but they're totally edible. If they won't be pleasant in the meal you're making, keep them for this Vegetable Rösti with Poached Eggs.

When citrus fruits become smushy or begin to brown, the interior and the juice it holds may still be perfectly useable. Juice your aging citrus and store the juice in a microwave-safe container in the freezer. Then you can zap it to thaw the top layer, use what you need and pop back in the freezer. If the peel is still good, zest before juicing and—you guessed it—freeze that too. Use it to (sorry!) add zest to cocktails, baked goods, risotto, vinaigrettes, compound butter and more.

Related: How to Store Lemons So They Stay Fresh

"Use by" and other label dates can be deceiving. A report by the Natural Resources Defense Council estimates that 90% of Americans misinterpret them, accounting for up to 17% of our household waste. These dates are not regulated or even required by the USDA (except on infant formula). If the label date passes but the item has been stored properly and there's no evidence of spoilage, it should be edible. So what do those labels actually mean? "Best If Used Before" indicates the manufacturer's advice on when a product will retain the best flavor and quality. "Use By" is the last date when the manufacturer considers the food will remain at peak quality. "Sell By" is used for inventory management only. Think of "Freeze By" as a clue to when a product should be frozen to maintain peak quality.

Related: 8 Foods That Last Way Longer Than the Expiration Date

Vegetable panade is basically an excuse to eat stuffing for dinner and a delicious way to combat food waste. Stale bread, random shards of cheese, leftover veggies—it's all welcome in the baking dish.

Wrap leftovers in reusable beeswax wrap; use a plate or elastic-bound cloth to cover them; or invest in a set of airtight containers with lids, and say so long to the clingy plastic stuff.

Related: The Best Food Storage Containers, According to Our Editors and Test Kitchen Experts

Xylem is the name of the vascular tissue in plants that transports water and nutrients, and you can harness it to keep foods like celery, asparagus and herbs fresher, longer. Store them cut-end down in a glass of water in the refrigerator to keep 'em crisp.

Egg yolks and whites are often called for separately in recipes. Refrigerate extras for up to 4 days. Turn leftover whites into macaroons or meringue, or whisk until frothy and add to that batch of homemade granola you're baking to form crunchy clusters with a boost of protein. Use the yolks to make your own mayo or a custard for ice cream. And either can be whisked into whole eggs for omelets, frittatas and scrambles. Or freeze whites and yolks for up to 3 months.

Herbs wilt quickly in the fridge (how often have you discovered liquefied cilantro in your crisper?). Turn the rest of the bunch—including tender stems!—into all-purpose green sauces like pesto or salsa verde, blend them into softened butter to season seafood and vegetables, or puree them with a bit of oil and freeze in ice cube trays to give an instant hit of flavor in rice, soups and sauces.

Related: 23 Simple Pesto Recipes That Make the Most of Your Summer Herbs

Zone in on the warm and cool areas of your fridge. The warmest spot is the door, so stash your condiment collection there. The lower shelf tends to be the coldest: keep eggs, dairy products and raw meat there. Since heat rises, put things that aren't as prone to spoiling on the top shelf—think: jams, hummus. And keep your produce in the crisper drawer—that's what it's designed for!

Related: The Best Ways to Organize Your Pantry, Freezer & Fridge