i have had a word with someone else face to face about the problems i was having and there is a simple answer:
remove the control from the list of mutant weights and then use the second model to compare that control weight to the mutant weight.

however my problem is not what i dont know how to lay it out in a table that R will understand
at the moment it looks like this:
light zinc seed weight

it needs to be like this:

plante number light zinc control weight mutant weight


however my problem is that mutant weight is comprised of 3 different weights which all need to remain in the same column but need to be linked to the same control ~(of which there is only one)

have i explained myself well enough?