If a tow-behind aerator is skating over the lawn and leaving dimples instead of pulling actual soil cores, the cause is almost always one of four things, checked in this order: the soil is too dry and hard for the tines to bite, there isn't enough weight on the machine to drive the tines in, you're towing it too fast, or the plug spoons are assembled backwards. Adding weight helps, but only once the soil itself is soft enough to penetrate, and the right amount of added weight is a spec your machine's own manufacturer publishes, not a number worth guessing at.
Here is the checklist in the order that actually matters, because weight is usually the third thing to check, not the first.
1. Check soil moisture before anything else
Dry, hard soil defeats a tow-behind aerator no matter how much weight you pile on. The tines need soil soft enough to penetrate cleanly and pull a core, not just dent. The standard fix is to aerate a day or two after a good soaking rain, or to water the lawn deeply the day before if rain isn't in the forecast. You're aiming for soil that's moist but not muddy; if you're leaving standing puddles or the tow vehicle's tires are sinking and slipping, it's too wet, and if the tines are barely marking the surface, it's too dry.
2. Check the tine or spoon orientation
On plug (core) aerators, the hollow spoons need to curve the same direction, toward the ground on the leading edge, to actually scoop a core out as the drum rotates. If a spoon or a full row of spoons was reassembled backwards after cleaning or storage, it will drag across the surface instead of biting in. This is a common cause after a machine has sat in a shed over winter and been reassembled from loose parts. A quick visual check before you start towing, confirming every spoon curves the same way, catches this in under a minute.
3. Add weight, using your machine's own published capacity
Once soil moisture is right and the spoons are correctly oriented, weight is what drives the tines deep enough to pull a full plug rather than skim the top inch. Tow-behind aerators are built with an open or enclosed tray specifically for this, and manufacturers publish how much that tray is rated to hold. That number varies by brand and width, so it's worth checking your own machine's spec plate or manual rather than assuming a generic figure:
- Agri-Fab lists its 40-inch and 48-inch tow-behind plug aerators with a weight tray rated up to roughly 140 lbs, per the company's published product specifications.
- Brinly-Hardy rates its 40-inch tow-behind plug aerator up to about 150 lbs of added weight, and its 48-inch model higher still, per the manufacturer's own listed capacity.
Those two examples show the range: capacity climbs with the width of the machine, and it is model-specific enough that "just add some weight" isn't a real instruction. Check the tray's rated capacity before loading it, since exceeding it can bend the frame or stress the hitch, and don't assume a machine you're renting has the same rating as one you've read about online.
Common ways to load a tray to spec: bagged sand or gravel (easy to portion to a known total weight), suitcase-style tractor weights if you have them, or clean concrete blocks stacked and secured so they can't shift or bounce off mid-pass.
4. Slow down
Ground speed affects how cleanly the tines pull a plug. Going too fast, especially once you've added weight, can cause the spoons to rip through the soil rather than pull a clean core, which looks similar to "not working" even though the machine is biting in. A slow, steady walking pace (or the lowest comfortable gear on a riding mower or garden tractor) gives each tine time to fully penetrate and extract before it comes back up.
Putting it together
| Symptom | Most likely cause | Fix |
|---|---|---|
| Tines barely mark the surface | Soil too dry/hard | Water deeply the day before, or wait for rain |
| Spoons drag instead of scoop | Backwards assembly | Check spoon curve direction before towing |
| Shallow, inconsistent plugs | Not enough weight for the soil density | Load the tray to the machine's rated capacity, not a guess |
| Torn, ragged holes instead of clean plugs | Going too fast | Slow the tow speed, especially once weighted |
Work through them in that order. Adding weight to dry soil, or adding weight without checking spoon orientation first, is a common way to spend an afternoon and still not get clean plugs.
A safety note on hitching and loading
Before hitching the aerator or loading weight onto the tray, make sure the tow vehicle, whether that's a riding mower, garden tractor, ATV or UTV, is stopped and the parking brake is set. Load weight evenly across the tray so it doesn't shift the machine's balance to one side, and secure loose items like blocks or bags so they can't bounce free while towing over uneven ground.
FAQ
Why is my tow-behind aerator not pulling plugs at all? Check soil moisture first; dry, hard ground defeats even a correctly weighted aerator. If the soil is soft enough, check that the spoons are assembled facing the right direction, then add weight up to your machine's rated tray capacity, and slow your tow speed.
How much weight should I add to a tow-behind aerator? It depends on the machine. Check your model's manual or spec plate for its rated tray capacity; manufacturers like Agri-Fab and Brinly-Hardy publish different limits depending on the machine's width, generally in the range of 140 to 200-plus lbs for consumer tow-behind models.
Can I use too much weight on a tow-behind aerator? Yes. Exceeding the tray's rated capacity can stress the frame and hitch and isn't necessary once the tines are already pulling clean plugs. More weight past that point doesn't improve results and adds wear.
Does watering the lawn before aerating actually make a difference? Yes, it's one of the biggest factors. Aerating dry, hard soil is the single most common reason a correctly weighted machine still fails to pull plugs.
Is it normal for a rented tow-behind aerator to need extra weight? Yes. Rental units are usually sold and rented without any weight loaded, since the appropriate amount depends on your specific soil conditions that day, not a fixed setting the rental counter can preset.
For the difference between a plug (core) aerator like this one and a spike aerator, and why one of them is a better match for compacted or clay soil, see plug vs spike aerator. If you're still deciding whether renting equipment like this is worth it versus buying, see is it cheaper to rent or buy a lawn aerator. And for how aerators fit alongside dethatchers, scarifiers and power rakes overall, see the four machines separated.
