OK, we all know that succulents are low-water plants. But they’re not “no-water” plants. Although they may survive without irrigation during the heat of summer, they’re unlikely to be lush and healthy.
I suggest that you ~
— Check your automatic irrigation system. Trust me, it needs it, and maintaining it can mean life or death to prized plants. Watch for leafy growth blocking sprayers, clogged riser heads, and plugged drip lines.
— Pay keen attention to soil moisture during heat waves and desiccating winds.
— If the root zone goes dry, supplement auto irrigation with hose watering. (See my canary-in-the-mineshaft way to evaluate evaporation in my latest video, Succulents, Sun and Summer.)
— Water early in the morning or late in the day. Note to desert gardeners: Watering in midday heat can literally cook roots. (Eek!)
— HOWEVER, aeoniums, dudleyas and other succulents that have closed their rosettes should be watered minimally or not at all, lest dormant roots rot. The plants will revive when the rains return. (They may not make it until then, though, if in full sun. So, shade them.)
— If the ground is concrete-hard, leave a hose dripping overnight to create an underground cone of moist soil.
— Trees and shrubs want water where their canopies would naturally direct rainfall: around the perimeter of the plant.
— Add gravel topdressing around succulents (or use organic mulch for woody plants) to help hold moisture in the soil.
— Take the opportunity, when hose-watering, to blast pests, fallen leaves and dirt out of leaf axils and the centers of rosettes.
— Use a hose-end sprayer—ideally one with multiple settings—to direct water where you want it.
— A hose lying in summer sun may contain scalding water. You already know this, but your house-sitter may not, so be sure to mention it.
— If you have a hose-full of hot water, aim a fine spray skyward. Droplets will cool by the time they hit leaves.
What about potted succulents?
From my website’s FAQ’s: Aim to keep soil about as moist as a wrung-out sponge. About once a week should do it. Water thoroughly to soak the roots and flush salts. Let common sense prevail: Water more during hot, dry spells and less or not at all during periods of high humidity, cool temperatures and rain.