For dry summer months, LADWP’s watering regulations aren’t limitations, they are good gardening sense. Don’t water if it’s running off the surface (fix the surface problems – see “sandy soils” above). Don’t water before 4pm or after 9am because evaporation in the hot sun means your plants aren’t getting the benefit of the water you apply. By watering in the evening, your soils and plants have the entirety of the cool evening, relieved from baking summer sun, to soak in the water you apply. If you are watering in the evening and you are experiencing mildew problems (happens a lot with roses), first, be sure you are keeping the leaves and tops of the plants dry. Water the soil, not the plants. Secondly, examine your plant spacing. Is there adequate space between the plants for air to circulate? It might be that you need to lift and resituate an ailing plant. Mildew issues are far less due to evening watering patterns than they are an indicator of other problems in the garden. Thus, follow LADWP recommendations and water as the sun eases from the sky.
In the Community Garden at Holy Nativity, we have a watering responsibility schedule. If it is your day, that means it is your day to do the one-finger test and evaluate watering needs, not just simply wield the hose. Our volunteer coordinator tends to populate the calendar for 2 or 3 volunteer visits per week in cool moist months, which we bump up to daily volunteers in hot dry weeks. All volunteers are asked to observe garden signage (“new plantings like moist soil” or “likes dry conditions”) as well as using the one-finger test prior to applying the hose. As a volunteer, upon arriving at the site you can make a quick pass around the garden to do all your observations and one-finger testing. You’ll then know, later when you have hose in hand, what needs water and what doesn’t.