Poly bags and lst

[SOG420]

Up to this point my friend hasn't been able to lst using poly bags. I'm sure there's an easy solution I'm not seeing. Here's a couple of picture of cab grow veg all but two plants were transplanted and watered yesterday

[SOG420]

most of the plants in polys are a cross between Purple Kush(burgundy container in back) and a High yielding indica dom bagseed I dubbed 10/6( male plant in blue cup)