I purchase laundry detergent in the large size (less packaging) and the bottle has a great afterlife as a watering can.
All you need is an empty, rinsed out laundry detergent bottle and a drill.
I like to put lots of holes in the lid, about 15 or so. This doesn't take much time but you may have to run your drill in reverse to get the drill bit out of the lid.
I keep containers by my kitchen door and fill them when I'm warming water before running the dishwasher or shower.
Give a quick tip of the jug for a gentle splash of water or squeeze the sizes to get a steady stream going.
Be well and happy gardening!