Rick writes

I have a "garden" which has more nettles than anything else. Garden is
a sort of loose phrase, its a bit of a mess.

I want to start a multi year project, where year one is is get rid of
the nettles, year 2 is to do the landscaping and do the grass, and
then year 3 is to think about plants. I don't want my new grass filled
with nettles that I burried during landscaping.

Can I put a weedkiller down that kills nettles & roots ? Right now I
don't care if it kills everything, as long as I can grow stuff next
year I am fine.

Any recomendations ?

Yes, I'm afraid you can't treat it as a building project where each
stage is definite and fixed and follows logically from the others. I
think you should be aware that the weeds will not simply stop growing in
years 2 onwards simply because you weeded in year 1, and also 3 years is
a long time to wait before you start using the garden.

I'd do 1/3 of the area every year, or as much as I felt I could take on
and do all the stages. So, pick a spot, get rid of the nettles in that
spot, sort out some landscaping, and plant it.

Year 2, you will have to maintain what you have done in year 1, and you
will get some weeds back around your new plants, but at least they will
have started to grow and you will get some benefit.

In this way your garden will evolve and you will get new ideas or modify
existing ones. If you have grass, then keeping it and planting small
shrubs in it will make it easier to maintain. Each year I extend the dug
area round mine as they grow, until finally the earth circles meet up
and all the grass can be removed and the maintenance is very simple
because I'm dealing with mature plants.

--
David