Collecting water brings up how to water a garden, when rain does not fall. A forest works well to capture rain water. I read some years ago, that a hardwood forest will absorb 70% of the rain water before it makes it to the ground. The forest canopy, 60 to 80 feet up, the understory trees, 20 to 40 feet, bushes and brambles up to 6 feet tall, then grasses and mosses each catch some raindrops on their leaves. Each time you remove a layer of the forest, whether by cutting a tree or letting deer eat all of the understory bushes, more of the rain will reach the ground, and potentially run off. Manicured acres of lawn are just a little better than a gravel road for holding rain. Watering with a sprinkler over a yard in which most of the layers of plants have been removed, is not like a rain storm. Most of the sprinkler water will run off or evaporate. What water does not flow away will most likely lead to mold or fungal problems on the plants. If you use a sprinkler, morning is the best time to give the water time to soak in before heat vaporizes it, and to let the plant leaves dry in the sun.
Drip irrigation systems place the water at each plant. These are good for permanent shrub beds with featured bushes. Soaker hoses, buried a few inches under the mulch work well distributing water more widely but at root level, and under the moisture protecting organic cover. Both take more preparation time to set up than running a sprinkler off of a hose. But, if set up correctly drip systems and soaker hoses can be easy to turn on during dry times. These can be set up with timers to turn on and off the water, for regions with predictable dry spells. In humid regions, a timer might soak the garden the morning after a thundershower. Being attentive to weather cycles and soil moisture uses your water source more carefully.
Hand watering is precise, but labor intensive. This is not practical for large gardens, but can be useful for specific plants or beds. When we lay out the “Three Sister’s Garden”, we arrange each hill of corn, beans, and squash such that we can hand water them until the plants are growing strongly. We use circular forms around tomatoes and peppers. These create water wells around each plant that are easily to fill for deep soaking during a dry spell. Many deck pots now have water wells in the bottom which we can fill either through a pipe at the soil surface, or through a side opening. In addition to avoiding getting the leaves wet, which contributes to mildew and evaporates more quickly, the water draws up from the base to the roots.
Watering buckets begs the question of what water source you can use to fill the buckets. Tap water either draws water from a well, or uses public water that has been processed enough for human consumption, which most plants do not need. Rain barrels can be a good way to refill the bucket without draining the aquafir. Another source is “grey” water. “Black” water is the stuff in the toilet, or otherwise tainted with something you do not want fuss with. The best that you can use to reduce waste here is “If it’s yellow, let it mellow. If it’s brown, flush it down”. But, we will leave black water alone.
Grey water is used water from washing dishes, clothes or bodies. A little dirt, soap, or body odor is perfectly fine for watering plants. If you hand wash dishes, during garden season, a pan in the sink can be emptied into those deck buckets. Washing machines, dish washers, and bathtubs are a more difficult to set up to drain into the yard. I recall the Vicar’s former house had a hose that soaked the lawn with some suds with each load of laundry. Vicar’s Dad has been a proponent of recycling for years. I recall growing up with a bucket in the shower to catch the water used to warm up the shower. A friend recently recalled using the water from canning vegetables for flushing the toilet. If you do use grey water in buckets for potted plants, do not let it stand too long… unless you like your deck to develop the aroma of a brewery in Milwalkee.