First things first, unless you're seeding and/or have a lot of thatch, there's no need to dethatch.

Do you think my worry about the electric dethatcher is warranted?

No, it will come back anyway. When it does, spray it with a triclopyr based herbicide like Weed-B-Gon CCO to kill it for good.

Yes, I will be reseeding. This is one of the reasons I love this rake! I did use some Borax on the patches. I might just stick with the manual raking as it is making a huge improvement. I will probably do a sample patch with the machine...just out of curiosity.

Great, post some pictures and let us know how it turns out!

I have one of those electric dethatcher, I had to remove half the tines, every other one, to get the right amount of "manipulation" without pulling all my grass out by the roots

What patches are you talking about?

Why did you use Borax on the patches? Borax kills everything once you go over the limit of not very much at all. It doesn't sterilize the soil, but it makes it unsuitable to grow plants and grasses.

Where do you live?

What kind of grass are you seeding?

Creeping Charlie will come back even if you use a magical dethatcher, it is that tenacious. However it makes sense to use the tool that makes your chore the easiest. No comment re: borax as know nothing about it.

I am in Eastern Canada and use a Scott's blend - from Costco. I used the Borax in a mist bottle - 1 litre to 1 oz Borax, I believe. I did it last week. I was pretty target specific.

Most of my yard focus has been on my gardens and have slowly been giving the lawn some extra attention. Most of my gardens are established so I plan on focusing a couple of seasons on the lawn now. I had to quit the raking - it is way too hot and sunny now. That probably won't be so great for the root system so I will wait until it cools again. It is unseasonably hot today.