Good management. Use your watering calendar to coordinate
your by-hand watering with Nature's watering; teach kids how important it is to
measure and record moisture, to ensure a consistent supply for growth.
Mulch. Evaporation will waste water quickly if you
haven't "dressed" your garden beds with a layer of mulch. Mulch captures
moisture and reduces evaporation (and your efforts spent hauling hoses and
watering cans), but it can't do it all.
Rain barrels. See the article
explaining how they recycle rainwater for your garden.
Dripline irrigation. By installing drip irrigation before
building garden beds, you'll only have to manually water seedlings and new
transplants. Once their roots become established in the rich organic mulch, you
can let the irrigation system take over. Students should still check the garden
regularly to make sure the system is working, and record data in the watering
Recyclables. You can also use gallon milk jugs or 2-liter
soda bottles as free, slow-drip watering tools. Using a pin, punch tiny holes
in the lower half of each jug -- both bottoms and sides. Bury them in the bed
near plants and fill them, and they will slowly leak water that plants can use.
You might challenge your students to design and test other irrigation tools
made from recyclables.