Rotary tilling near established trees

belter

Hi guys,

I have quite a few large mature trees around the yard that i would like to re-turf. I want to rotary hoe and improve the soil before laying turf. I would like to know how close i can rotary hoe to these trees without mauling their root systems. I have mulched areas under them so i wouldn't till much closer than the drip line and it would also only effect approx 1/4 of the dripline of the trees. It is safe to do this? Trees in question are 2 gums, Pin oak, and papery bark tree (common street planting esp. around richmond melbourne)

Thanks in advance.

Eric Frei

Have you taken soil cores and seen what you got to say a depth of 300mm?

Often rotary hoeing in urban yards is not the answer.

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belter

Not cores exactly but i have dug other parts of the yard and at around 200-300mm there is yellow clay with a few little rocks.

Brent Ferris

Trees do better on slightly acid soils, with higher fungal populations, grass does better on more alkaline soils with higher bacterial populations. The two really don't go together. And grass under a tree normally grows poorly, if at all, -- not enough light!! unless the branches are removed to perhaps 20 feet up. Then the tree isn't doing too well. Keep the roto tiller away from the trees and the tree roots. Grass does better if just seed-- roto tilling destroys the microfaunal populations, and these need to be re-established before the plants and trees can grow well.

Eric Frei

If there's clay at 200mm to 300mm why rototill?

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Brent Ferris

As Eric says, if the clay is 200-300 mm deep, why rototill? You already have -- or presumably have good topsoil. Rototilling will destroy any tree roots you contact, and you already have workable soil. Additionally, few grass species will grow in the shade of trees - waste of money, laying turf. If you want to throw money away, lots of people here on the forum could give you better ways and places to spend it.

belter

Thanks for the responses, response to above; to break up the top soil from years of compaction so the turf takes. Is ripping any better? The turf is not going under any trees dripline just outside of it as mentioned in the original post the trees are mulched. Seeding isn't really a sustainable option in oz the seed grasses are too thristy or are weed problems. I have done the rpz calculations so tilling outside of this zone is ok?

Eric Frei

Ripping is better but coring is even better and that's what they do on golf courses.

There's a lot of info here ....

Soil Aeration Experiments| Grade Changes| Compaction| Decompaction

As far as staying outside of the TPZ (as per AS4970) you should be OK but again, without a site inspection no-ones giving an iron clad guarantee.

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belter

Thanks for the reponse Eric. I have construction planned near some trees so i will get a report before i start digging around.