Questions: How much land would a serf have to tend? What was the ratio of bonded men to free men? Did the peasantry own any of the agricultural land or where they all sub tenets of the lords?
Thank you for your time.
Medieval property laws are really confusing and vary greatly with time and place. However, there are some things I can clarify for you. In Judith Bennett's A Medieval Life: Cecilia Penifader of Brigstock c. 1295-1344 Bennett explains the complicated nature of manorialism and land ownership. To paraphrase, in the Early Middle Ages manors were worked mainly by slaves, but as time went on slavery fell out of use. By the eleventh century, it was close to a 50/50 split between serfs and free men. Serfs were not slaves, but they didn't own their land and had to provide service to their lord. Freemen, however, either leased or outright purchased their land from each other or lords. However, while there was significant amount of variation among the peasant class, they were still far below the social status of even the lowest noble. It would be a mistake to think of serfs as slaves and to think of freedmen as truly "free". Lastly, as to size of land, it varied widely even from county to county. However, during the Late Middle Ages, in England around 5 acres would be considered a small amount of land for a family to tend while 30 acres or more would generally mean the owner would hire day laborers to help cultivate it.
tldr: It varied, and they didn't have to. It varied, and either could be serfs. Yes, no.
Serfs, be they free or unfree in their person, rightfully possess land their lords own, in return for services.
A serf's ancestors could be unfree (mostly) slaves put on (and bound to) a plot of land, or free commoners who gave part of their working capacity (and/or own land) up for protection of a lord and possession of (more) land. The ratio of unfree serfs generally decreased as 1) slavery went out of fashion so there was no supply, 2) they were able to buy their freedom saving up surplus income "provided" by growing commerce and development of agriculture, and 3) the Black Death (and other depopulating events like Mongol raids) decreased labor supply so commoners becoming serfs were able to negotiate better terms.
Both types possessed land they didn't own. They weren't obligated but had a right to work this land, and enjoy (most of) its fruits. They were obligated to do various services in return, hence the term "unfree land". Besides this they could actually own land (though it's extremely unlikely in the case of unfree serfs) they retained (or got) when becoming serfs. Non-serf commoners of course owned land.
Services could be anything from craft items (for landed craftsmen) to a portion of said "fruits" and labor, to (more and more likely) money. Labor service is the part where serfs did have to tend land; their lord's manor. Manorial lands could be separate or (if the village rotated plots) grouped in with serfs' plots. It also included transporting resources or goods, helping construction or repair of buildings (walls, roads) etc.
Plot sizes... were portia unius familiae, enough for a family, at least initially (don't forget, the goal was to reliably have accessible labor). This changed for the better with improving farming methods (the same land yielded more), and for the worse with worsening conditions (climate, weather, arability etc.) and distributive inheritance.
(please note, this is a theoretical framework of an institution thoroughly abused in reality)
The manumission of William Wythington illustrates freedom, possession and service very well.
Im unsure if anyone will ever read this as the post is outdated but before i create a new one how much cultivated land was it possible for a serf to tend under optimal conditions with the technology of time.