Roots Question

I am new to growing wheatgrass. My attempt seems to be successful. I have five trays started. The oldest will be ready for harves in a few days, but I noticed roots are slightly turning brown on the bottom. What does this mean. I do not have holes in the trays. Would holes help for ventilation to keep them white, or does it matter? Thanks for the insight anyone is willing to share.

One reason could be the summer heat...Where are you located????

Adding ventalation and keeping air between the trays may help.

The second reason is toooooo much water at the end of the grow cycle.

Too much...not enough and JUST RIGHT. Just practice.

Dead roots may change the flovor of your wheatgrass.