Do you know of a formula or online calculator that will tell how many plants is the right number to have in an office? Perhaps per sqft or # of people? it just seems that having 18 plants (per some online articles) in an area of 1800 sqft seems little excessive, it will look like a jungle. Unless we are not talking of a plant being one pot. For example, english ivy or pothos, how many plants do you consider to be a normal pot? One? or the number of stems? -- I am doing a project and will like to present proposal to get plants for the office, but need to know what is the right number and back it up.