If at planting the soil is too dry and there is no rainfall foreseen, yes – it is recommended to irrigate. Water will penetrate through the resin coating and start dissolve the nutrients inside. The release back into the rooting zone is precisely steered by soil temperature. So irrespective of the amount of irrigation/rainfall, Agroblen releases small amounts of nutrients according to plant’s needs. Keeping a constant moisture level of the soil will improve product’s performance!