How to aerate a lawn. Step by step guide
Aerating your lawn helps with compaction, shallow-rooted plants, and wet soil. Compacted soil means that the soil has lost its macroporosity (space in between particles) due to heavy use or constant foot traffic. Shallow rooting plants mean that only the top layer of the soil has been turned over, which leaves weeds exposed to sunlight and dry air, killing them off much faster than if they were growing in a healthy level of hypoxia (oxygen deficiency). Wet soil causes roots to rot, accelerating disease rates in plants while at the same time suffocating them by drowning their roots in water instead of oxygen. It also stops normal gas exchange from occurring, which cuts down vigor and overall plant health.
Aeration is the process of pulling 1-inch plugs out of your lawn to relieve the compaction. This allows fauna (microorganisms, earthworms, etc.) to make their way down into the soil to help with decomposing dying roots. Dethatching your lawn would be done after aerating it, as dethatching should only be done before seeding or sodding a lawn. Aeration should occur every other year, but it depends on how compacted your soil is. Once you start seeing healthy turfgrass growth, you can lessen the number of times you aerate each summer by half until further notice if desired.
What equipment do I need?
The best equipment for aerating is core aerators. These are simple machines that have hollow tines (prongs) attached to a power source. They work by removing plugs of soil in order to relieve compaction. Hand aerators remove small cores of soil instead of large cores like what you would get with a core aerator. These are good for areas that regularly receive foot traffic or where the lawn is mostly weeds and brush instead of turfgrass.
Shovel/spade – these can be used to manually pull out 1-inch plugs from your lawn if needed, but it will take forever, so I recommend either renting an aerator or using a hand aerator.
I have clay soil, should I still do this?
Yes! The most common misconception about aerating is that it only benefits sandy soil. Clay has compaction issues just like sand does, so do not let this be an excuse to skip aeration. The process of digging up the plugs will help break up some of the clumps in your lawn which helps with drainage, allowing oxygen and water to get down into the roots instead of running off or staying on top of them (which happens more often than not). It also breaks up thatch layers preventing further accumulation by speeding up decomposition rates.
The best time to do this is during late spring once your last frost has passed but before summer hits.
This way, any new weeds won’t germinate until after you’ve dethatched (if you plan on dethatching again) and seeded/sodded.
When should I aerate?
For best results, wait until late summer/early fall so that new growth has a good chance of penetrating through the cores and taking root before winter comes around (even though the cores will be visible for about a month or more). If you can’t wait, then cut back on watering and fertilizing since excess moisture and nutrients in the soil can mask how hard (or easy) it is to push an aerator through your lawn. The closer to fall you aerate, the less watering/fertilizing that will be necessary leading up to winter, reducing stress on your lawn.
If you can’t aerate at the right time of year (around late August/early September) because of the weather, then you can still do it at other times but be aware that it will take longer for your lawn to green up, depending on how far into summer it is. Since aeration reduces soil compaction, you should receive less runoff during rainfall events if done properly, so watering requirements may either stay the same or even go down a little bit in some cases. If your lawn needs more water after aerating, there are probably deeper issues involved that need to be dealt with using other methods before breaking out the core aerator again.
You should not try to aerate when soil conditions are wet since this creates muddy areas that will bake into the soil and create a hardpan (a compacted layer that water can’t penetrate) if it dries out, which makes future aeration efforts much more difficult. After a good rain event, the best conditions are well established where the ground is still wet but not nearly as muddy as before.
What about core aerators? Are they all created equal?
There are many types of core aerators but the most common ones on the market today have hollow tines that cut into the soil and pull out plugs as large as 1-inch in diameter. Other types include spike aeration, slit tine, solid tine, etc. A spike aerator has spikes instead of hollow tines, so it’s more like a push machine with less pulling power than some other machines. It will not do as good as a job as a regular aerator, but it does help prevent further compaction if done at the right time, which can then help increase root growth and microbial activity.
The one that I rented from my local rental center was this machine here:
It had two separate handles that could be pulled to make it easy to control/steer back and forth across the lawn. The tines were spaced out evenly, but you still want to overlap your first pass by 1/3 of the area at a minimum (you’ll see why later).
You will need to do multiple passes over large areas and spend more time aerating compared with hand aerators since push machines can only go as fast as its operator lets them move, which is usually pretty slow if they’re doing their job properly (the downside of push machines is that they tear up the grass since there’s no depth control).
Rental centers typically charge about $40 for a full day on a walk-behind machine, but some places offer multiple-day deals for a slightly higher price.
If you’re planning to buy one, they usually start around $100 and go up from there depending on the type of aerator and what accessories are included. If you have a small lawn or don’t plan on using it more than once in a while, then I would not recommend buying an aerator.
The most expensive ones on the market cost roughly 3x as much as renting ($150-$250) but can be faster and do a better job compared with renting if done properly by the owner. It is also possible to buy a used one from Craigslist or an auction website, just be sure that it is in good condition.
How do I find the best deals on core aerators?
You can pay anywhere from $25-$200+ for one, so it should be easy to get the best deal once you know how much money you’re willing to spend beforehand. Sales typically occur around springtime when people are starting to plan their lawn work for the year, but you may find that some stores will have them on sale at other times of the year, which is why it’s important to keep checking back.
Whenever possible, try to purchase one outright instead of leasing. There are sometimes deals found online where you can get an extra discount if you buy it in full before a certain date or get free shipping/delivery within a certain time frame.
The vast majority of core aerators will fit any standard tractor, so once you get one home and attached, then driving around your yard shouldn’t be too difficult. If your lawn is large, though, then you should consider renting a larger model with more powerful motors attached, which makes getting through tough soil much easier while sacrificing some maneuverability.
If this still works out more than you are comfortable paying for something you’ll rarely use, why not consider aeration shoes as an alternative. Not only are aeration shoes much cheaper, but are far easier to store. On the downside, you’ll have to do the job manually so best get started exercising those leg muscles!
What should I do after I’ve aerated?
Aeration can also help increase populations of microorganisms in your soil which causes decomposition rates to increase as well, so don’t be surprised if it takes longer for thatch or cores to disappear after adding this task to your lawn care schedule.
Mowing over the cores/plugs might cause them to spread around, but they are easily visible, making them easy pickings when mowing by hand. Hand raking is another option so long as the tines on your rake aren’t too wide (which would make plugging more likely). If you plan on dethatching and/or seeding/sodding, then it would be a good idea to remove the cores from the lawn before spreading your seed or laying sod.
Do I need to water after aerating?
No, aerobic conditions should remain until the plugs have firmly rooted back into the soil, which normally takes 1-2 weeks, depending on soil type and weather conditions. The only time you would want to water is if you live in an area with long periods of drought or use a dry core aerator (which is not recommended).
How do I know if my lawn has been properly aerated?
The plugs will last a few weeks to a month, depending on the time of year and your soil type, so don’t worry about removing them immediately. You can tell by stepping on them -if they feel spongy. You have more compacted areas/layers, so continue to do passes over those areas until the cores start feeling hard underfoot (a little firmness is okay but should never compress down completely). If your grass was recently overseeded/sodded, then keep track of how long it takes for the cores to disappear since this could prove valuable info if you decide to aerate on your own next year, so you know exactly when the right time is to do it.
How do I take care of my lawn after aerating?
The top 1/2 -1 inch of soil should dry within 2-3 hours, but any large clumps found in the aerator’s path need to be picked up immediately since they could die off during hot weather or contain weed seeds that could cause an outbreak later on. Be careful while raking them up, so you don’t damage your machine while getting all of them removed. If you can wait, then you should let the plugs sit for a few days before removing them with a rake or leaf blower, which will make it easier to get out as many as possible.
If your soil is too wet or compacted (like clay), then the cores may not break apart very easily and could take weeks/months to disappear completely, which means that there’s still a lot of compaction going on below ground. In this case, you need to use other methods for breaking up those layers first before aerating again otherwise, you risk injuring yourself by running into obstructions while mowing/raking/blowing off your lawn.
You have hopefully learned from my previous guides how important it is to maintain healthy soil if you want to get the best results from your lawn care efforts, but you should also make sure that any core aeration work gets finished by the end of fall since colder weather could prevent new roots from forming which will result in dead spots appearing during the next summer.
No matter what type of soil you’re dealing with (clay/sandy/loam etc.), having a good amount of organic material mixed into it helps it drain properly and holds onto water better while also providing nutrients to plant roots so they can grow stronger and absorb more nutrients. In addition, applying mulch after aerating helps keep soil temperatures lower since there are no plugs lying around to bake in the sun, which makes weed seeds less likely to sprout once springtime rolls around again.
It’s also a good idea to know what type of grass you have in your lawn before applying any fertilizer since certain types are more resistant/susceptible to damage from nitrogen-based fertilizers. Dethatching your lawn every summer is recommended for all types, but grass that has stolons (runners) might be better off with an aerator instead since dethatching can damage those runners, while removing plugs would be much easier on them.
What are the important steps to take after aerating?
Even though you’ve put all that work into getting your soil prepared, if you don’t do anything else for your lawn, then it’s unlikely that you will get many results from your hard labor.
Most people wait until fall arrives before tossing any fertilizer or seed on their lawns while waiting for springtime to plant/water them, but core aeration can be done whenever since there are no seeds being planted at this time. Of course, the best time to apply mulch would be in the late summer/fall, so it has enough time to settle into your soil before winter. However, it can also still be beneficial even if applied during the wintertime, which means you don’t have to wait another year to get the benefits of this low-cost, natural method.
What is the best method for applying mulch after aerating?
It’s always better to err on the side of caution when it comes to safety, so you should wear long sleeves and pants while working on your lawn just in case any small pieces fly off unexpectedly, which could cause scratches/cuts. Also, it may be worth taking along a pair of elbow pads if you’re using an old set since they will take most of the impact from constant banging into rocks/bricks without doing any damage (unlike your hands).
If you can afford it, then renting a compactor with some overseeding equipment attached is definitely preferable over making multiple trips back and forth with your vehicle, but it’s not always possible for everyone to have their own equipment since they are usually pretty pricey.
The most important point is to try and remove as many of the plugs as you can before laying down mulch because they will continue working underground no matter how long they’re left there, which means that adding extra soil on top might just bury some of those cores further into the ground where they won’t break apart very easily as they should.
If you don’t want to use any type of cover crop (like clover), then make sure that you wait until the very end of fall when growth starts slowing down before applying anything, or else there’s a risk of killing off your grass/weeds by accident if it decides to keep growing while you’re trying to protect it.
I hope these tips have given you a heads up on how to get started when you aerate a lawn and the importance of doing it regularly. If you have any questions, then please post them in the comments section below.