I am trying to find a spray to kill weeds out of monkey grass and not harm it.
Weeds in Monkey Grass
Certified GKH Gardening Expert
Your best bet would be to hand pull as much as you can and then add mulch to keep weed growth to a minimum. However, you could also try sprinkling corn meal in the area, which has a chemical in it that acts as a pre-emergent on plant seeds preventing them from germinating. Sprinkling corn meal will not harm plants but will keep weeds from growing. Another option (though not one I enjoy recommending) is the use of conventional weed killers. Here is an article that you may find helpful: https://www.gardeningknowhow.com/plant-problems/weeds/conventional-weed-killers.htm