Which is more affective ? They cost about the same for rental . But if i use a core aerator i still have the process of spreading the seed to do . But the overseeder of course puts the seed down for me . Help please .
In my experience it really depends on how much work needs done. The slit seeder works great for total renovations or large bare areas. If yard is in pretty good shape and you are just trying to fill in bare spots I have found that if you set your slicing depth to hit the bare spots the machine will get hung up and bog down on the surrounding turf whuch will be higher, otherwise you will slice the good turf and not even touch the bare spot. In this case aerate and overseed might be better. This experience is with Bluebird slitseeder, other brands might be different.
I think it all depends on the type of overseeder. Many just cut slits in the soil & have a hopper dump the seed out. They work okay, but IMHO you get as good or better results w/ double aeration & overseeding w/ this method. IF you're talking about the unit that has the tubes which inject the seed into the soil, then I think that is a good way to go.
The machines are used for two different purposes -
The core aerator is useful for loosening turf that has been compressed by either being a walked down [pathways] or being a play area [children or adults] or heavy mowing equipment.
Even rain compresses out all the air spaces, especially if there is lots of clay in the soil. The core aerator pulls out thousands of soil plugs and lets the soil loosen up and relieves the pressure on the root system of your turf grass.
If you are far enough North that the ground freezes a foot deep in winter, the ice usually heaves and loosens the soil , so it's not as necessary to plug in the Spring up North. The best and most effective time to do it is early Fall, after the kids, and mowers, and the dog have all stomped it down hard.
An overseeder or slit seeder is usually set to only cut into the soil an inch or less. This loosens the very top of the soil a bit, and it sure racks up the thatch in a lawn, but it is doing this so that the grass seed that is being dropped will likely fall onto moist loose soil and germinate. If you overseed and apply a good dose of fertilizer now - that lawn is going to look like its on steroids by mid May.
The best way and surest way of doing it right is aerate first and overseed after. I own both types of machines and have done hundreds of lawn rennovations and can tell form experience that you need to aerate and overseed both to get the best results possible. If you have a good stand of grass, you can aerate by making 3 different passes and get results as well. If it is bare or a new lawn install, aerate and overseed. It may be costly to rent both if you don't own any of these machines, but you should figure that cost in before an estimate.
Depends on situation. If it is a decent lawn I aerate heavily and broadcast seed. If it is a bare lawn or new lawn, I aerate and broadcast seed and then use my Ryan Mattaway overseeder. This is the most complete way of doing it. I have never had to go back and do areas after using these methods. All customers have been very satisfied as well.
One other option is using an areo-vator to overseed with. Some come equiped with a seed box that drops the seed down on the tines while areovating. For those that dont just broadcast seed before you areo-vate. The areovation will penetrate the soil and the vibration of the tines will fracture the compaction and help level the lawn at the same time.. The vibration also buries the seed below the surface insuring good soil to seed contact. I apply half the seed and areo-vate in one direction and then broadcast the remainer and areo-vate in right angles to the first pass. So far I have had excellent results with this method. Even on bare soil. The areo-vator works best on soil that is dry. and is a good way to incorporate not only the seed but the fertilizer and liming materials also.
I believe core aerating to be superior because it exposes the existing grass's root system to more oxygen which in turn causes the roots to go deeper and it allows the redistribution of the nutrients on the surface as the plug dissolves for the seedlings,
I've always made sure to aerate the entire lawn 2x's in a crosshatch pattern when I'm overseeding-not too pretty but works very well,