I have chemdawg, gorilla cookies, unicorn burst, runtz auto. OG runtz photo, queens banner 3, purple rocketry, iced gusghers, another night owl that starts with an M. 21 plants total
If you're growing in dirt or in separate hydro tanks, no. My first RDWC grow was Green Giant and Skunk #1 in the same loop. Bad idea. Nute strength that the Skunks loved were too hot for the Giants, so I wound up starving the Skunks to keep the Giants alive.
All said and done, it turned out OK. I haven't made the same mistake since.
According to me, it is not bad for growing the multiple strains. When you grow several plants of the same strain, it means that your plants will require the same nutrients and watering regimen, and it ensures a fairly even canopy so that all your plants receive sufficient light for good yields. You can also expect to harvest your plants at about the same time. In short: If you grow only one type of weed, it can make things easier.
I grow in soil in separate pots so I can feed as needed per strain. Or you can grow in 5gallon DWCs and do the same thing. Different needs for different strains.