I save our cat litter jugs, generally the 14# jugs, poke several drainage holes in them and bury them a couple inches next to plants in the garden. Take off the lid, fill with water, put lid back on. Seems to work for me to water more quickly by hand, make sure the water gets down under the soil level. Grandkids like watering that way too. Pretty easy to add a bit of water soluble fertilizer into the jug and allow the water to seep out. If I can't bury them a bit due to more mature plant roots, I drive a short piece of rebar through the opening, into the ground to stabilize the jug.