How to help along a slender weaver bamboo privacy screen

Hello everyone, novice gardener here! Recently transfered a few slender weaver bamboo out of smaller pots and into these planter troughs with mostly bagged potting mix. Using some seasol every couple weeks and added osmocote once. Problem is they are mostly in shade under a large jacaranda. Trying to water consistently which can be tricky with these short days. Any ideas on a good drip feeding system? I know they’ll take some time but keen on hearing any other ideas on how to help them along Thank you!