You can place a layer of cardboard over the grass, and then top it with soil. Enough to keep out the undesirable grass, and it will break down over time. Try to avoid cardboard with colorful dyes and keep to the basic brown.
Interesting. I never heard of this method. Thanks.
(some) cardboards made for long distance shipping have insecticides and fungicides in them
Solarizing is the easiest way to do this, but it takes a lot of patience. Depending on your area you may need to start now to have your site ready for spring planting. Search for a guide on exactly how to do it, but basically you cover the grass in clear plastic to create a greenhouse effect that will kill the grass and any seeds. You water before putting down the plastic to encourage seeds to germinate. Once you're done (four weeks minimum, more is better) you remove the plastic and plant your plants.
Depending on the type of grass you have, tilling may not be effective. It also may be very difficult if your area is as rocky as you say it is.
Another option is to use a shovel to dig up strips of sod and flip them over. This should be almost as effective as solarizing, but it's much faster (no waiting) and much harder work.
I think this is the option I will go with. Might have to apart next year though because we won't be getting much more in the way of sunshine soon.
If you have the time to do it, it's absolutely the best and easiest way. It's hard to postpone landscape projects, but doing them in the right season is setting up your project for success. Good luck, and don't forget to take progress pictures!
Rototill it. The sod mat will stop things from germinating if you use cardboard.
What do you mean the 'loam is very thick in rocks'?
Loam is a textual class, not a soil horizon.
I'm assuming you have a lot of rocks in your topsoil. As long as you can till without ruining your tiller, go for it.
I replaced a grass yard with clover a few years ago and didn't have much success with any of the "cover it until it dies" methods.
Chopping the sod wasn't good for me either, so I gave in and used Agricel Grass Out a clethodim herbicide that only targets grasses.
According to what I could find, it isn't harmful to birds or bees once it dries. It dissipates in the soil in 3 days. It is slightly bad for fish but that's only a concern if you spray directly next to a stream/creek.
I looked at EPA reports as well, but the summary by the Minnesota Department of Natural Resources is easier to read https://files.dnr.state.mn.us/forestry/certification/pesticides/dnr-esra-clethodim.pdf
I know it isn't exactly what you where looking for, but if the other methods don't work out I recommend this.
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