self-watering container system - to cover or NOT to cover?

[nniemiec]

i'm growing toms in a gutter / wick self-water system & am wondering what expert opinion is on covering the top of the 18 gallon totes w. a plastic cover / with slits for plants to grow out of vs. not covering at all?

My thought is to cover them = better soil consistency (soil doesn't get water logged from heavy rain) , but is there a practical reason for NOT covering the totes?

what do you recommend & why? thanks!