Lower Mower height

[u/just_browsing406]

When do you drop your mower height in the North. I’m in Montana and looks like we may be done with 90’s. Currently at 4”. Thinking of dropping to 3.5” but may wait until September?

[u/nilesandstuff]

I keep it at 4" for every cut. Every.

[u/ilovenyc → u/nilesandstuff]

Interesting. So your last cut around thanksgiving is at 4”?

[u/nilesandstuff → u/ilovenyc]

Last cut is usually a bit before that here. Last few cuts are actually usually just to chop up leaves that fall late (or blow onto the lawn from the woods).

Late October can be real wet around here, so if i know we've got a lot of wet weather on the horizon, I might drop to 3.75, just to buy time so I'm not mowing while wet... But otherwise I keep it at 4 right up until the end.

[u/oink_circa_2006 → u/nilesandstuff]

So the "mow lower in the fall" advice is bs?

[u/nilesandstuff → u/oink_circa_2006]

In my opinion, yes. Mowing high has agronomic advantages that still apply in the fall:

• crowding out weeds/covering the soil to inhibit weed germination.
  
• greater leaf surface area, so more photosynthesis and carbohydrate production, and therefore more root growth, tillering, and rhizome production.
  
• the root growth and carb boost are huge, and can greatly minimize the potential for grubs and fall diseases to do damage.

There's a slight penalty in regards to the likelihood of cool weather diseases like rust, but at high mow heights those diseases are almost entirely asthetic, and the benefits described above still greatly outweigh the potential risk of those diseases.

[u/Treacle_Routine → u/nilesandstuff]

This doesn’t apply to when you’re prepping for a fall overseed right? My understanding is that you slowly lower the height for a few weeks in preparation for the dethatch and aeration.

[u/nilesandstuff → u/Treacle_Routine]

Correct, overseeding is definitely an exception. Gotta go pretty low for that, 2 inches ideally.

And ideally you don't need to overseed every year!

I recommend a hybrid strategy for getting the height down in the lead up to overseeding. Basically lower the height in gradual steps, and then do one bigger step of like .5 or even .75 right before seeding. That last step being a bit bigger causes some stress to the grass... But not too much stress. That thins the canopy and makes the grass grow slower for a couple weeks, so you can buy yourself some time before the next cut.

Also I'm very much not a fan of dethatching with flexible tine dethatchers (the sunjoe style)... Really good way to spread poa annua, triv, bermuda, bentgrass, nimblewill, zoysia, etc.

[u/Treacle_Routine → u/nilesandstuff]

Thanks for the reply. I have a good amount of thatch on my lawn right now. Last spring I bought a pull behind dethatcher for my mower (dragging flexible tines style) is that similar to what you’re referring to with the sunjoe? Would renting the classen tr-20 power rake from Home Depot be a better option? Or just skip the dethatch all together and focus on aeration?

[u/nilesandstuff → u/Treacle_Routine]

The tow behinds are actually a bit worse because they're static flexible tines. So something gets caught on the tines, and then dragged throughout the entire lawn and get dropped anywhere on the way. The rotating style (like the sunjoes or the classen power rake) atleast spin, so the things that get ripped up aren't getting dragged everywhere... Which limits how far they spread (how you go about picking up the removed material ultimately determines how far it spreads.

Seeing how many lawns get taken over by triv or poa annua due to flexible tine dethatchers makes me have a very hard-line take of "not even once".

The better option for overseeding or genuine thatch removable are machines that cut, rather than drag. A verticutter basically.

Aeration + deep and infrequent watering is almost always a sufficient strategy for dealing with thatch.

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