The Best Homemade Fly Trap for Outdoor

Learn how to DIY a fly trap that actually works using a mason jar (a soda bottle works too) and bait. These results are 100% real from my own backyard using household items and a stinky bait.

Homemade fly trap made out of a mason jar and a construction paper cone hangs on a brick wall.

This fly trap DIY works so well outside for green bottle flies, aka blowflies, that it’ll turn your stomach. How’s that for an endorsement? But more than the trap, the most important thing about this DIY – is the fly trap bait.

Living in an almost 200 year old house with backyard chickens means I’ve learned how to control a lot of pests.

The best time to control pests is BEFORE you see pests.

Catching flies is a whole lot easier if you start baiting before they start mating.

Get your fly trap made and placed outside a couple of days before warm weather arrives to keep the population under control from day 1.


Getting rid of fruit flies is a reader favourite.

Mouse in the house? How to get rid of mice.

Controlling flies with natural predators like parasitic wasps.


So when one of my chickens became sick with flystrike, a deadly affliction caused by bottle flies, I knew I had to head into battle against them.

I made and compared a few homemade fly traps including:

  1. a mason jar with paper cone
  2. a soda bottle with the top cut off and inverted
  3. good old fashioned fly strips (not DIY but I had to test them out!)

The results showed the trap wasn’t so much the determining factor in how well a homemade trap worked – it was the bait.

Mason Jar & Paper Cone Trap

Baited with raw shrimp.

Homemade fly trap hanging on red brick wall filled with flies because the right bait was used.

SUPPLIES

  • Mason jar
  • Standard sized sheet of paper
  • 1 raw shrimp
  • water

INSTRUCTIONS

  1. Roll a piece of paper or cardstock into a cone and tape it together.
  2. Put the cone into a mason jar of any size, making sure there’s room at the bottom of the jar for at least 2″ of water. You may need to adjust the shape of your cone.
  3. Add water and a single raw shrimp to the jar.
  4. Wait.  Within a couple of days your jar will be FULL of flies.

Yep. A raw shrimp allowed to rot in the sun for days until it has the putrid smell of liquid internal organs.  That was the key to a successful fly trap.

DIY mason jar fly trap filled with flies.

Soda Pop Bottle Fly Trap

Baited with commercial, store bought fly bait.

Homemade fly trap hanging on red exterior brick wall showing no flies in it.

This is the basic DIY fly catcher you see all over Pinterest.

SUPPLIES

  • Plastic soda bottle
  • Scissors
  • Commercial fly bait

INSTRUCTIONS

  1. Cut the top off of the plastic pop or water bottle.
  2. Flip the top upside down (it’ll look like a funnel) and stick it back into the bottle.
  3. Pour a couple of inches of water into the bottom of the trap and then bait it.

In this experiment I used I used store bought fly bait.  The container is a 2 litre pop bottle.  The flies can get into the bottle, but can’t figure out how to get out.  Then they drown.

This trap caught NO flies.  Not a single one.

But it isn’t the design of the trap that was flawed, it was the bait. Store bought fly bait attracted no flies at all. 

Fly bait is the most important part of your fly traps.


Fly Strips

The fly strip cost a couple of dollars and dangled sadly from my window frame enticing no flies at all, just hanging there like a limp tongue.

I wanted to make sure I gave all the fly traps a good shot so I kept them all out for a week.  This is how things had progressed after 4 days.


Fly Trap Results

Mason Jar with natural fly bait (shrimp) – Caught HUNDREDS of flies in 4 days

Soda bottle with commercial fly bait – Caught ZERO flies in 4 days

Fly strip – Caught 7 flies in 4 days

After 4 days it was pretty clear that the rotting shrimp was the only way to go in terms of bait.

My homemade fly trap recommendations

The trap

Either the mason jar or soda bottle method will work very well to catch flies outdoors.

The bait

Raw shrimp is your BEST choice for fly trap bait.


For this experiment I only baited the soda bottle with commercial bait (which caught nothing) but since then I’ve tried it successfully with shrimp as a bait. It works just as well as the mason jar with paper cone.

Testing Different Baits

I experimented with different baits including:

  • Fermented chicken feed
  • Raw sweet corn 
  • Fresh chicken poop*
  • Raw shrimp*

* If you use meat, seafood or poop understand that this gives the flies a place to lay their eggs. That means if you use any of these things that after several days you will ALSO have maggots appear in your fly trap. Consider this when choosing your bait.

The rotting shrimp was the winner by a shrimpboat load.

The only issue with the enticing smell of rotting shrimp was the vile smell of rotting shrimp.  If you place your container up high enough (above nose level) you miss most of the stench but given any kind of downward breeze you suddenly feel like you’re walking through a rotting whale carcass.

By day 7 I was pretty sure I would have to try something else because I couldn’t stand the stench of the shrimp no matter how well it worked.  Then a funny thing happened.  By days 8 and 9 the trap was so filled with flies they actually suffocated the smell of the shrimp.  Yet somehow the stink was enough to continue to attract the flies.

By day 14 the mason jar trap was almost completely FULL of flies.

The huge success of a mason jar as a fly trap shown as it hangs on a red brick wall filled with flies.

Home Fly Trap on Day 14

Because there were so many flies I couldn’t smell the shrimp at all and the jar was almost full.

After 20 days it stunk again. Stunk like the guts of a hot monkey. But the stink could have been the mass grave of flies as well.

Mason jar fly trap hanging on exterior red brick wall, filled with flies after 14 days.

To save myself some grief and whatever happens to be in my stomach, when it comes time to remove the jar I just  tie a plastic bag around my head, put a lid on the jar and throw the whole thing in the garbage.

Just kidding. I don’t tie a bag on my head. I’m an excellent breath holder on account of my cat’s horrific gut issues when she – coincidentally – eats seafood.

Fly trap placement

The best place to put fly traps is actually AWAY from where your fly problem is.  (The dog run/chicken coop/picnic area.) The point is to draw the flies way from wherever it is they’re fond of.

What is the best home remedy to get rid of flies?

The best way to get rid of flies around your house is to use TWO methods.

  • Parasitic wasps (really just tiny little flying things that are in no way as menacing as their name alludes to) will kill most flies before they even become flies. The wasps kill them in the larvae stage.

AND

How Do I Get Rid of Flies Inside?

Well, I’ll tell you … a bottle filled with stinking, rotting seafood probably isn’t the best way. But if you fill a bottle with some non stinking fly bait like the liquid recipe below, it won’t be quite as offensive.

This recipe won’t work nearly as well as rotting flesh but it will work to catch flies.

Fly Bait Recipe

  • 1/2 cup water
  • 1/2 cup vinegar
  • 2 Tbsps sugar
  • 1 Tbsp dish soap (the dish soap breaks the surface tension of the water and vinegar, making the flies unable to use it as a launching pad when they fall in it)

Use either the mason jar or plastic bottle method. You can use a small water bottle instead of a large soda bottle.

Now that you’ve mostly eliminated one insect from your yard (totally understandable, flies are sex crazed monsters that feed on crap and then land on your corn on the cob), you might want to help out another.

Learn how to raise monarch butterflies on you property, something I’ve been doing for over a decade.

If you have a great fly bait recipe, leave it in the comments below. If you have a great maggot story maybe just keep that to yourself.  Just kidding. Obviously, I’d love to hear the maggot stories.


 

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The Best Homemade Fly Trap for Outdoor

258 Comments

  1. Joe says:

    Hi Karen
    i read on this post somebody calling you a little scientist. which i agree. Therefor any suggestions on Japanese Beetles? We have tried traps, nematodes with no success, spraying at different times to eradicate the egg laying time period, pupa stage and of course grub stage. Skunks are now in looking for the grubs. If you can solve that problem i am nominating you for a Pulitzer award.

    Thanks joe in Woodstock

  2. Pamela Hancock says:

    We use rotten eggs. Yes eggs work better than the store bought bait. But we bought the traps and just reuse them.

  3. Yolanda says:

    Hey Karen!
    Any thoughts about feeding the dead flies (strained out of the shrimp slurry) to the chickens? Because protein.

  4. Andrea says:

    What if you use the plastic bottle technique with the shrimp bait? It just seems like a waste of a mason jar. Lol

  5. Leilani says:

    Amazing how many comments you are still getting on this article! I have to say you cracked me up the whole time too. Thank you for the laugh and the advice. Will definitely be trying something like this soon near (but not too near) our coop area!

    • Karen says:

      I have a jar filling up with flies in the coop as we speak. :) Or type. Whatever. You know what I mean I’m sure. At one point earlier in the season I had 3 jars lined up on a windowsill and they were ALL full and writhing.🤢 ~ karen!

  6. Vicki says:

    This is gross but I use dog poop instead of shrimp to lure the flies. I have raccoons that come around and was afraid they would like shrimp. Everyone know flies can’t resist poop. In the house I have a jar with apple in it along with the apple cider vinegar and brown sugar. Water to of course.

    PS: If you try the poop wear gloves and still wash your hands afterwards. 😁

    • Karen says:

      Yup. That’d be gross, lol!! I had 2 raw shrimps going for the past 2 weeks. And by week 2 they were both full AND started to stink. So I’ve started with a fresh one. I’m not sure I’d ever get brave enough to use dog poop, lol. ~ karen!

  7. Kansas says:

    You’re funny! And helpful :)

  8. Sheila Selby says:

    Rotting shrimp huh? Well I’m up for anything that will kill s#*t flies as we call them here on the farm. Just try getting your tongue around that number sign/asterisk combo, no easy task. We’re not just farmers by gawd, we’re linguists.

    As for the sticky traps, I buy them by the dozen and fill ’em up faster than I can hang them. I use them as a last stand when the flies have breached the no-fly zone in the goat shed. The “disgustabags” we get from the feed store and hang at the required distance apparently don’t hold the same appeal as goat pebbles and milky kids.

    The principal value of sticky traps is when you lure unsuspecting people into your goat shed on the pretext of “helping” with the kids. “Watch the fly traps,” the obligatory disclaimer. Visitors will dutifully duck and weave their way through the fly-spotted fiesta streamers to the kidpile in the back corner. Then they forget.

    First, there’s the frozen moment when they feel the tug in their hair. Then the tarantula dance ensues, you know, where they try to paw it off without actually touching it. Unfortunately, the sticky tapes are equipped with nasty sharp tacks that I don’t want lost in the goat bedding, so when the dance has reached a fever pitch I usually reach out and pluck the tape off instead of grabbing my phone and filming, which is why you’ll just have to take my word for how much fun it is.

    A little-known fact about barn flies: once trapped in your vehicle, they never leave. Four windows down at, let’s say 100 km, and they are still in the truck cab, while every McDonald’s napkin and piece of unopened junkmail has been sucked out in the vortex. I’ve taken them on a four-hour round trip to the city with me. People stare.

    It’s probably the sticky trap hanging from the rearview mirror.

  9. Mark says:

    Not a very definitive post. Were you testing fly traps or fly bait? I am not sure. But when you put a different bait in each trap you have tested neither. Was number 2 a good trap with bad bait or a bad trap with good bait? To be even rudimentally scientific you need the same bait in each trap each time so three tests. You proved nothing accept that a particular combination works. But would the shrimp in the soda bottle have been even better?

  10. Christina says:

    My husband and I have weak stomachs, so I had to find an alternative bait. I used one of those kool-aid single serve packs in about 1/4 cup water with a dash of creamer, in an inverted water bottle. They can’t resist. Granted I’m using this indoors and not in competition with chicken poo.

  11. Joe Mota says:

    Excellent post Karen. Now if we can only figure out a way of annihiliating Japanese beetles at any stage, egg, larvae pupa and grub would be a great accomplishment. These babies do a lot of crop damage everywhere.

  12. Melissa says:

    I died laughing reading this post! Thank you so much for the information and the laughs

    • Karen says:

      You bet! And it’s actually a fantastic fly trap too! Which of course isn’t as important as laughing, but hey … it’s something, lol. ~ karen!

  13. Now that’s gross but the results are fascinating. Thanks for sharing your real experience. Cheers, Elna.

  14. Kelly C says:

    My mom stubbed her toe quite badly on her patio furniture. Her big toenail broke and there was a little blood. She sat down and put her foot up for awhile. Fast forward several days…her toe was throbbing so bad she couldn’t sleep or walk. She went to the hospital because of the pain and they decided to remove the toenail. Well ….the doctor jumped back so fast when the nail came off and he yelled. My mom sat up to see what happened and a ton of maggots were spilling out of her big toe. A fly had landed on her toe as she sat with her foot elevated that day she stubbed it! Doctor had never seen anything like it before! Now I’m terrified of flies and will definitely try your method!

  15. Cheryl Fencl says:

    Does anyone have anything that works for crickets? We have a horrible problem with crickets in our chicken coop.

  16. Patricia says:

    I love it that you do experiments to find the best possible solution for a problem. I also use this method. Thanks for all your hard work!

  17. Louann says:

    We just use a 2 litre plastic bottle like the coke or sprite ones. Instead of cutting the top off and inverting it like you did, you just burn some fly sized holes through the plastic in a ring around the bottle – a couple of inches from the top. We put in a few pieces of Kapenta (a dried fish) and some water. Leave it to rot like the shrimp and then it starts attracting flies. when it comes time to empty the bottle, take the lid off, tip it out, rinse it. Restock and away you go.

  18. Elizabeth A Chase says:

    Hi Karen! Thanks, this will help sooooo much! I don’t have chickens, but I do have dogs and myself that get bothered by flies, as I live in a very wooded area. I get deer flies, or horse flies, or whatever they are; bite so hard I have a welt for days! I ended up finding some disposable traps at Walmart, no less! I hang one up & it catches all kinds of flies. Pretty soon, I can go out to garden without constantly waving my hands around like a lunatic! LOL When I run out of the fly traps I purchased last year on clearance, I will be doing this! Thanks for the great info!

    As a side note, I also have wasp problems, so I tried one of those soda bottle things for wasps that I found on Pinterest, and caught zero wasps in it. I’m right there with you, girl!

  19. LS Nelson says:

    Why not bury the contents? It would be more religious, easier, might fertilize something nearby, and would stink less.

  20. Marie Lybrook says:

    Use window fly traps. Available online. You could make your own but it would be messy.

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