Weed Control in Onion crop The field should be kept weed-free, especially in the initial stage of plant growth, as weeds compete with the crop and reduce the yield drastically. Being closely planted and a shallow rooted crop, hand weeding particularly when crop is in full vegetative stage, is difficult and expensive. It is recommended to use weedicide along with one hand weeding at critical stage. Application of Fluchloralin or Oxyfluorfen @ 15ml/10 litres of water 3 days after transplanting followed by one hand weeding 45 days after transplanting effectively controls the weed population. Alternatively, application of Pendimethalin (3.5 litres/ha) immediately after transplanting and before the first irrigation coupled with one hand weeding gives the best results.