Web Garden is the web hosting system which comprises of multiple “processes”. This means that we have a single server on which we run multiple processes. This type of hosting provides logical scalability to our web applications.
Web Farm is the web hosting system which comprises of multiple “computers”. This is different from web-garden as web garden runs on a single server while a web farm runs across multiple servers. This provides physical scalability to out web applications. This type of set up is achieved using Load balancers to balance calls coming to the server using a dedicated process that forwards these calls while maintaining the health of the multiple servers.