There’s nothing like a bowl of cool washing up water to please a thirsty plant or lawn!
How best do you water those patio plants? Well if you can avoid letting them dry out to wilting point, its better to soak them thoroughly one day, then let them go the next day or two without watering. if you water every day the compost is too wet and the roots quietly stew. Its better to take a deep drink, dry off and get some oxygen to the roots.
When the lawn is frazzled by the heat and growth is minimal, lift the mower cutters a little from their normal height so that you are only topping the tufts rather than cutting the whole surface. It keeps the lawn greener and the grass stronger. If it has dried out and is starting to brown or sound crisp underfoot, keep off. So long as it has not been worn away ,grass always comes back with the rain.