How to Kill Fleas: 12 Best Flea Killers to Kill Fleas in All Life Stages

So it has come to this. You are researching how to kill fleas and ramping up for battle. You’ve finally run out of patience with FAQs and interesting facts about fleas; you’ve tried all of the precautions, you’ve cleaned your home top to bottom and you’re still getting nowhere.

Which brings you to me and this article; you want the nuts and bolts – what kills fleas and which options are best suited to your situation?

Let’s dive right into it – here are the best flea killers to win the war against fleas!

How to Kill Fleas: 12 Best Flea Killers

When you set about to kill fleas, you must take into account the fleas’ life cycle. As you may know by now, flea infestations are notoriously difficult to get rid of, especially if you’re only targeting the adult fleas.

Keep in mind that the majority of any flea infestation consists of pre-adult fleas and make sure you combine strategies that kill both adults and baby fleas.

Here are the top flea killers and exactly which flea life stages they kill.

Diatomaceous earth

Great for killing: Adult fleas

There’s so much to cover that I almost don’t know where to start – exciting, this flea murdering business. Let’s cover diatomaceous earth first of all; perhaps the MVP when it comes to dealing with leggy home intruders of all varieties, with fleas top of the pack.

DE is a naturally occurring substance, which means it’s non-toxic and works in a low-key manner, making it preferable for homeowners with children and roaming pets. DE is slightly slow-acting, but its fundamental mechanic is to attach itself to the fleas’ exteriors as they wander through the applied area.

Over time, the powdered granules start to suck the moisture out of the flea, eventually killing them by dehydration, leaving you with a lovely carpet of husky flea shells. Nobody emerges unscathed from war, I guess.

Application of the powder is fairly simple; just choose areas that you know to be dense with flea activity, or places that you suspect are a welcoming environment for them. Spread liberally, leave it for at least a week and then vacuum up the corpses.

Note: Keep in mind that as effective as DE is, it does have downsides. For starters, since it has to make contact with the fleas in order to work, it can take awhile for you to notice the flea population declining. But the biggest downside of DE – and the reason why we advise you use it along with an IGR pesticide (more on this later) – is that DE will only kill adult fleas since it’s only effective against hard-bodied insects.

Unfortunately, flea larvae and eggs are soft-bodied so DE won’t affect them. And considering they make up the majority of the infestation, you really want to use something that will kill them off.

Boric acid

Great for killing: Adult fleas

The logical progression in our war against fleas is to move on to Boric acid. This compound works in a similar way to diatomaceous earth but might sound a little more familiar to you; especially if it’s your designated chore to handle the laundry and dishwashing duties.

The granules in boric acid also kill fleas predominantly through dehydration from the outside in, but are also known to be toxic if consumed by the creatures, acting as a sort of stomach poison. On the bright side, their little stomachs will be clean as a whistle when they go to visit the great flea in the sky.

Application is, again, similar to diatomaceous earth – simply pinpoint the locations around the home (furniture, soft furnishings, thick carpets etc.) and sprinkle the boric acid or Borax liberally.

Some important notes, however: Borax has been known to cause issues with breathing in cats, so it’s one to be wary of if you have any pets around the home – at the very least, try to keep this compound away from pets’ bedding. Also, unlike DE, boric acid can be toxic if ingested so you may want to skip this solution if you have pets or young children around.

Last note: Borax and boric acid are effective in combating adolescent and adult fleas but have no real effect over their eggs – same as diatomaceous earth. The protective layer of the egg itself means that the powders never get a chance to inflict the larvae with their dehydrating power.

Mother Nature; she’s thought of everything. Again, you’ll have to go with an IGR to wipe out the flea babies. Or…

Vacuum

Great for removing: Flea eggs, flea larvae, flea pupae, and adult fleas

Now, surprisingly, using the vacuum to kill fleas is a contentious point amongst the flea-killing fraternity. Yeah, there’s a flea-killing fraternity. The get-togethers are pretty dry affairs.

It’s worth noting straight off the bat: vacuuming alone is unlikely to kill flea eggs but it can suck them up so you can dispose of it far, far from your home and is a solid, all natural strategy to get rid of fleas in most other life stages.

Part of the killing power is down to the actual machinery of your vacuum – if you take a second to think about it, your average household vacuum cleaner is really like a giant thresher for any beasties unfortunate enough to get caught up in it. All those brushes, wheels, air tunnels, heat, spinning bits and loud bits and aaaahhhhhhh!!!

All of this brutal physicality is thought to strip the fleas of their protective outer shell and leave them susceptible to the dry, arid air of the vacuum and suffocate/dehydrate them. If the actual action of the vacuum doesn’t do it, then the compacted bag or dust-bin area is sure to finish them off.

Even better news? The vibrations from the vacuum can stimulate flea pupae to leave their cocoon, which makes it easier to suck them up into the vacuum. Because the cocoon is resistant to insecticides and often spun around the base of the carpet fibers – they can be very difficult to kill or remove. Enticing them out of it is the best way to deal with them.

The most important part of vacuuming, of course, is to make sure that you are disposing of the bag/emptying the contents appropriately. Remember that eggs may still survive and some Rambo-esque fleas might’ve struggled through the process…You don’t want those tough suckers back in your home.

Tip: One smart way to make sure the fleas don’t survive the vacuum is to stick a flea collar inside the bag – this will kill off any remaining fleas that survive the sucking.

Heat

Great for killing: Fleas in all life stages

The vacuum discussion brings us along nicely to this next tip…Heat.

Now, it’s probably common knowledge that part of your home’s appeal for fleas (and the appeal of your pets) is heat; they seek a nice, warm environment to do their blood sucking business. Usually, the clammier and more humid the better.

But there is such a thing as too much of a good thing. In this case, too much heat will fry them through and through and this applies to every stage of the lifecycle: no matter how big, small, young or old they are – fleas cannot withstand temperatures above 95 degrees or thereabouts.

The easiest way to achieve these heady heats is usually to toss your bedding, clothing and whichever soft furnishings you can into a high temperature cycle on your washing machine and then immediately toss the cleaned fabrics into a dryer for a huge blast of warmth.

This is a tried and tested means for killing off fleas in droves – and it saves you having to shell out for a professional exterminator or racking up huge heating bills. But what about things you can’t machine wash?

Steam

Great for killing: Fleas in all life stages

Steam is your answer.

For sofas, carpets, rugs, hard furniture and anything else you can’t toss in the dryer – you want to look to steam, and more specifically a steam cleaner which allows you localize and target certain areas. Such focused blasts of steam will instantly kill off any flea (of any age) under its withering heat.

Plus, steam is a totally natural way to kill fleas and sanitize your space at the same time, which is great if you’ve got kids around and are looking for non-toxic ways to get rid of fleas in the carpet.

To do it, either rent a steamer, hire a professional cleaning service or get yourself a home steam cleaner. We recommend the Vapamore Primo Steam Cleaning System – it produces steam at a temperature of 214 degrees, which will kill fleas in all life stages. It is an expensive investment but it’s great quality and also comes with a lifetime warranty.

Flea traps

Great for killing: Adult fleas

If you’re new to the flea-killing game then it might surprise you to learn that there are actual bona-fide flea traps on the market. As with anything like this, though, there are about a million different brands to choose from.

The bare mechanics of these traps are more or less the same. You’re usually looking at a structure to contain fleas (akin to a glass bowl) which is floored with a sticky material to stop them moving.

Flea traps usually have a light or heat source to lure the fleas out from their hiding places in search of a nice, warm, bloody meal – or maybe just out of curiosity, I don’t know… I’m not a flea.

The point is, they come out to investigate, leap into the sticky bowl and bam! Good night. All you have to do is dispose of the corpses the next day.

DIY Traps

Great for killing: Adult fleas

If you, like me, hate spending money and you, like me, get a kind of sadistic kick out of making your own little pest-killing devices then you, like me, might be interested in DIY traps.

The DIY traps work on the same principle as the flea traps on the market – entice and contain. For a thrifty trap just fill a bowl (deeper equals better) with soapy liquid and place near a light source. The inquisitive fleas will come along, jump into the bowl and find themselves stuck by the soapy compound.

Nematodes

Great for killing: Flea larvae and flea pupae

Ever thought that what your flea-killing arsenal needs is a sort of forced cannibalism between pests? Then nematodes are the answer for you.

‘What the hell are nematodes?’ I hear you ask. My god. You don’t know nematodes? Everybody knows nematodes. Anybody who’s anybody knows nematodes… *frantically Googles*

Nematodes (often called beneficial nematodes) are microscopic worm-like parasites which are introduced into pest infested soil and gardens to feast upon the baddies. They’re generally safe and non-invasive to use around animals and plant life – although they do feed on decaying matter, so maybe keep your garden in decent condition, eh?

Nematodes seek out ‘hosts’, in this case flea babies – namely, flea larvae and pupae, and burrow into them through their skin and hollow them out by digesting them from the inside out. This process usually takes around 48 hours and then the worms move on to their next meal.

Beneficial nematodes don’t work for flea eggs or adult fleas but by killing flea larvae and pupae, the nematodes do help to stop the flea life cycle in its tracks.

Pretty hardcore for something the size of… well, nothing really. As stated, nematodes are usually most effective in outdoor environments – which is great for making sure that your lawn and garden is an inhospitable environment for fleas.

You can use them indoors on thick carpets or rugs for effective killing but you’ll need to do a lot of vacuuming up afterwards, then again… If you’re following this list, you’ll be vacuuming 24 hours a day anyway right?

Natural flea spray

Great for killing: Flea eggs and adult fleas

The last bastion in naturally occurring non-toxic flea killing weaponry: natural flea spray. Now, by ‘natural’, I don’t mean that this spray grows on trees but rather that the compound within these sprays is created with wholly natural ingredients: predominantly essential oils.

This makes them, for the most part, completely safe to use around children and most essential oils are okay for dogs.

Obviously, the easiest thing to do is just look around for the cheapest natural flea spray options on the market and then work by trial and error until you find your ideal solution.

However, if you feel like getting a little more creative with your time, there’s no reason that you can’t concoct your own natural sprays with certain ingredients, like peppermint, rosemary, eucalyptus, lemongrass, citronella, cedar wood oil, clove oil, thyme, and geraniol oil.

Just remember that dilution is key. A safe ratio to abide by is no more than 10% essential oil – you can fill the rest of your spritzer bottle with water or a carrier oil.

So, for example, if you’re using a 100ml spray bottle, only 10ml of it should be essential oils and the remaining 90ml should be filled with water or carrier oils like olive oil, coconut oil, and so on.

Flea foggers

Great for killing: Adult fleas and hatching eggs

Now we’re into the chemical warfare territory – no more naturally occurring, pleasant, non-toxic solutions for us; it’s time to ramp things up a gear.

Flea foggers, or flea bombs as they’re also known, are perhaps the most common form of pesticide for use in a domestic setting. Again, it would be impossible to list off the many different grades, brands and types of flea fogger available today – unless you want me to turn this into a massive catalogue… Which might not be a bad idea, I always find smacking bugs with a massive catalogue to be a great way to kill them.

Generally speaking, though, you’re looking at one flea fogger per room to truly clear the place out (depending on how powerful the pesticide is and the size of the room) and it should be able to kill adult fleas and ideally, pre-adult fleas.

Note: Not all foggers target both adult fleas and pre-adult fleas – make sure you choose a flea fogger that contain an Insect Growth Regulator (IGR) as well, like Precor Plus Fogger. 

As with any domestic pesticide, you want to make sure that all pets, small kids and anything else that might be affected by the chemicals is out of harm’s way before you set it up – they go off like small smoke grenades.

Once you’ve cleared the house of living things – get the rooms ready. People often overlook this step, but you want the chemicals to get everywhere; into every little flea-infested nook and cranny, so open drawers, cupboard doors, clear shelves and uncover shady spaces to let the clouds get everywhere.

Then high-tail it out of the house yourself for a few hours. With any luck, you’ll come home to a massive vacuum job. I never said it would be fun…

Best flea spray for home use

When it comes to sourcing decent pesticides for fleas to use inside the home, you’re looking at yet another heavily saturated market. Just off the top of our heads, we can think of at least a dozen available options that will get the job done.

But here’s what you need to remember: not all flea pesticides work for fleas in all life stages.

Generally speaking, most powerful and fast acting pesticides will work on adult fleas – but if you want to murder en masse and effectively, you need to focus your energies on wiping out not just the adult fleas but the juveniles as well.

Enter Insect Growth Regulators (IGRs).

IGRs are basically pesticides for younger fleas. They don’t necessarily kill these baby fleas but IGRs force a synthesized hormone onto the young or unborn fleas, which messes with their genetic makeup, meaning they don’t grow into healthy adults.

This is absolutely key to halting a flea infestation in its tracks, otherwise you’re just constantly fighting a battle with fully adult pests and never gaining any real traction. Remember, the majority of the flea infestation – like over 90% – are pre-adult fleas.

And even a few stragglers left over can be all it takes to keep your infestation growing, which is why you want to find pesticides with an insect growth regulator in the ingredients.

That being said, IGRs will not have an effect on already mature fleas, so it’s best to choose a flea killer spray that combines pesticides that target adult fleas with an IGR.

The good news? There are several of these sprays available on the market. Here are the best ones.

Precor 2000 Plus Premise Spray

This is quite possibly the best flea spray for home use. If you can only choose one flea killer, we recommend you get this one. Precor 2000 Plus spray contains a potent combination of two pesticides that will kill adult fleas quick – Phenothrin and Permethrin – as well as Precor IGR.

One can of the spray will cover 2,000 square feet and it goes on as a fine mist without much odor and it sinks deep into carpets and upholstery to reach flea eggs and larvae. It also dries fairly quickly, with no residue. Needless to say, it’s highly effective.

Virbac Knockout E.S. Area Treatment

Virbac’s Knockout Spray is every bit as good as Precor 2000 and it works in much the same way. It combines the pesticides – pyrethrins and permethrin – to kill off adult fleas quickly while the pyriproxyfen (Nylar®) IGR goes to work sterilizing flea juveniles for up to 7 months with just one spray.

One spray can covers up to 2,100 square feet and it goes on easily, reaching deep into carpets and rugs, upholstery as well as cracks and crevices.

More Flea Spray Options

The Precor 2000 Plus spray and the Virbac Knockout spray are two of our favorites. But they aren’t the only options when it comes to flea killers that brilliantly combine pesticides with IGRs.

So if you can’t get the above options or simply would like more choice, here are a couple more highly effective flea sprays for home use:

• PT Ultracide Pressurized Flea Insecticide

• PT Alpine Flea & Bed Bug Pressurized Insecticide

Pro Tip: These flea sprays are potent enough to make a huge dent in your flea infestation but even smarter is combining these pesticides into an overarching pest killing methodology for maximum effect.

We’re referring to the above flea killers such as vacuuming, steam cleaning, scattering diatomaceous earth and running everything through the dryer.

There ya go – the A-Z, inside and out list of tried and tested flea killing tactics. Do me proud.