Allotments 4 All

 Mine are coming up and I,m so proud of them ,I can hardly bare to thin them !  But I know it has to be done .   Ihave covered them with a thin fleece fabric ...is this correct ? and should I keep this on until harvest ? I have also done this with cabbages ....sorry to be a pain but ..same again ?
        Thanks all !   Rohaise    ::)