Farm houses in West Germany(Cologne, Bonn, Frankfort and Stuttgart)

In Germany, there are accommodations on farms, but I doubt that you would find them in cities like Cologne, Bonn, Frankfurt, or Stuttgart. Farm accommodations would be more likely in rural areas.

I doubt that booking websites are going to have many listings for Bauernhöfe (plural in German of Bauernhof). You'd probably have more luck looking on town websites, often www.(town name).de. Look for Bauernhof.

Use Google Maps to find small town around your desired big cities, look for town websites and Bauernhof or Bauernhöfe. Write to them in English. The likelihood of such places speaking English and responding to an email in English is not great, but try.

You need to be looking under Bauernhof Ferien, etc. for farmhouses.
https://www-landreise-de.translate.goog/?_x_tr_sl=de&_x_tr_tl=en&_x_tr_hl=en&_x_tr_pto=sc
https://www.bauernhofurlaub.de/

Not sure if there is anything near Frankfurt or any of the other cities but there might be. West and East Germany does not exist anymore. It is just Germany

All mentioned places are not very agricultural close to them.

In some regions you will find more manor houses operated as hotel or B&B (often called "Garni").

You can search also for wineries (Weingut) with such offering. But compared to Italy in most cases you will find these places in the villages and not as stand alone in the middle of the fields.

Thank you all for your suggestions.
Perhaps I should of been a bid more precise on my locations.
I meant in the villages near Cologne, Bonn, ... etc.
Of course there are no Farm houses inside the cities.
Thanks again!

I think a farm vacation in Germany is a different experience than an Agriturismo in Italy. My experience in Germany is that it is just accomodation and maybe some interaction with animals/tractors, etc. and does not have the food experience that I understand is a major attraction in Italy.

The largest number of ag-stay options in the general neighborhood of Cologne and Bonn is probably in the vineyard/winery category.

Winery = Weingut
Winemaker = Winzer
Vineyard = Weinberg

Winzerurlaub or "Urlaub beim Winzer" are some common German search terms that will turn up options for rooms/apartments in smaller towns and villages.

You can usually arrange a wine tasting or a cellar tour or sometimes a Planwagenfahrt, which would be a ride through the vineyards in a tractor-pulled wagon, often with a picnic lunch. Winemakers might offer these themselves or refer you to others nearby who do so.

I'd look near the Rhine and Mosel rivers first. Some of these places can be found on booking.com and similar booking sites. Here's a place in Hatzenport that may or may not suit you, one that I have bookmarked as a possibility for my own travels:

https://www.booking.com/hotel/de/weingut-1869-brunnenhof.en-gb.html

While booking.com is fairly thorough about details - the above page indicates that English is spoken by the proprietors, for example - I suggest that you also find the homepage for any place you are interested in, and run it through a translator if there is no English page available. You will get more info and you may even find that the rental terms (things like deposits, cancellations, etc.) are different from those on commercial sites. Here's the Brunnenhof's, for example, which indicates that wine-tasting sessions and Planwagenfahrts are available and that they have two apartments, not just the one which booking.com mentions.

https://www.brunnenhof-hatzenport.com/

Now, this place is on my list partly because I only travel by train (and connecting bus) in Germany these days. A location like Hatzenport gives me great access to other places I might wish to visit. Hatzenport is a quiet town with a beautiful river setting and access to other nice destinations like Trier, Cochem, and other Mosel towns.

https://www.mosel-inside.de/en/travel-guide/mosel-villages.html

It is also handy for access to Burg Eltz Castle (very popular with Rick Steves and on this forum) thanks to the direct bus connection from Hatzenport.

https://burg-eltz.de/en/homepage