Have you actually done this? Beware. The first website you listed I would not recommend. There are programs that make you think you are going on a trip to "volunteer" to take care of the elephants in India, or cheetahs in Africa. It's not volunteering for anything. It's just another way to market a trip.
WWOOF is supposed to be a World Wide Organization of Organic Farmers, and you go there as a volunteer to help them with the organic farming.
I just signed up to be a host for people who want to help me on my organic farm in Tuscany. I do not own a farm, and I live in San Francisco. To be a host it just asked for my first, middle, and last name. I wrote that my first name is, "No," my middle name is, "Lo," and my last name is, "So."
No Lo So means, "I don't know" in Italian.
It asked for a password of at least six characters. I wrote 1234567. It asked for the location of my farm. Even though I said it was in Tuscany, I gave them the address of an island in the South Pacific.
It then asked me four screening questions; 1. Have I ever been convicted of a felony. 2. Am I a sex offender. 3. Have I ever been convicted of a drug related crime. 4. Have I ever been convicted of causing emotional or physical injury to a person.
They didn't do a background check of my answers because as soon as I hit the send button I was accepted as a WWOOF host. It didn't even ask me if I have a certified organic farm, it just said, "Welcome as a WWOOF Host," and asked for my credit card information for the $50 annual dues to be listed on their website as a host. Of course, that's where I stopped.
It's like people who pay $500 a day to "volunteer" in Africa and and spend a few hours a day cleaning the the doo-doo from the barns of captive elephants, and throwing pieces of horse meat to lions in cages, thinking they are actually volunteering to help the animals in Africa. It's a smart marketing tool.
After passing screening to host people on my non-existent organic farm, I checked what it would be like to be a customer instead, wanting to volunteer on a WWOOF organic farm in Tuscany. They offered me the name of a place for 268 euros per day, but said I could only stay there it if I send in my credit card info to pay the $50 annual "donation" to become a WWOOF volunteer. So I checked the place on TripAdvisor and it's a regular B&B listed at the same price. And I wouldn't have to do things like pulling weeds to make me feel like I'm a volunteer, I could just go outside and sit by the pool all day.
So I changed my mind and wrote on their website that I wanted to volunteer on an organic farm in Albania, and it was the same spiel. In other words, these are just regular rentals, using supposed organic farming as a marketing tool. It even says on their website that if you have an organic farm in a country that doesn't have a WWOOF Office, you can, "be an independent WWOOFER," just send in the fifty dollar donation to be listed on our website as a WWOOFER host. No one inspects them to see what the place actually does. It is like Viator, or Craig's List. It's just a website for people to pay to sell their stuff on a website.
It's an AirBnb alternative with a different marketing scheme. You can pat yourself on the back by telling yourself that you are contributing to organic farming, while paying $300-500 per day to spend a few hours a day pulling weeds. The owner might let you ride around on a tractor, while pointing out a few things about the plants.
I believe that some people have been connected to well meaning "hosts" and spread some fertilizer, and listened to someone speak about organic farming for an hour before being sent out to mow the lawn, and had a good experience, but this is not agriturismo in Italy, it is just another way to market a hotel, a B&B, or a spare room.
You can actually stay at a real farm and help harvest olives to make olive oil, or to harvest or take care of grapes for winemaking, and do lots of great things, but you can't just trust a website like WWOOOF that says it can set you up to work next week at an organic farm in Zimbabwe, Togo, Azerbaijan, Bangladesh, or Belarus, or Bulgaria.
Although you cannot stay at the place in the website below, there are many farms like this that you should be looking for. They are abundant in Italy. People will not do your research from scratch, they can only help. This Forum is not a travel agency that does trip planning. Figure out where you want to go, select some places to stay and how to get there, and people will offer opinions to help you stay on track.
http://www.mozzarellamamma.com/2016/...man-winemaker/