Most outdoor plants do well with only occasional watering unless they are situated in very poor, free-draining soil or are struck by drought conditions, but those under cover need more attention. Plants can only thrive if they have a good supply of moisture to their roots.
The plants that need the most watering are container-grown or newly-planted. Plants that have just been put in the soil are prone to drying out because their roots are not yet established.
Always water the garden in the evening or early morning because in the intense heat of the Sun not only does water evaporate quickly, it can scorch leaves.
A way of reducing evaporation is to add a thick layer of mulch to the ground when it is moist. Aim to make the layer about 10cm or so. The layer should be organic material such as compost or well-rotted manure or alternatively you could use a membrane designed for the purpose.
When using a watering can or garden hose, try to direct the flow of water to the base of the plant so that the roots can benefit. Keep the flow gentle so that the pressure of the water does not erode the soil leaving any roots exposed. Soil needs to be soaked well otherwise the water will just sit at the top of the ground rather than sink down to where it is needed.
Embedding tubes or reservoirs next to a plant can help get the water from a can to roots quickly thus using water in an efficient way. Home-made reservoirs can be made from cut-down soft drink bottles. Water-retaining crystals are good to use in pots and hanging baskets; add them to the compost when you are planting up.
Garden hoses can be wound onto a reel to keep them neatly tidied away. Make sure you buy one long enough to reach the end of your garden.
Using a seep hose can save a lot of time, especially if you have a large area given over to growing vegetables or flowers. This is a long pipe with a perforated surface that leaks water along its entire length. Seep hoses can be laid along the top of the soil or buried beneath it. They are especially useful in low tunnels where plants are sheltered from the rain and access to them is difficult.
There are also greenhouse irrigation systems that can be connected to a mains water tap or water butt. A timer controls the supply of water to drip feeders. These systems are especially useful for people who work long hours during the week or need to be away from home for many days at a time.
Collecting water in butts from gutters is easy to do. The more roof surface area that can be employed, the more water you will collect. This water is a free resource for your garden and will be especially useful at times when water companies start to ration supplies. A thin layer of oil on the surface of the water will stop insects breeding in your reserves and a lid or grill will stop small animals such as cats or squirrels from falling into the butt and not being able to scramble up the steep sides to freedom.
A lack of water can cause your plants and crops to have problems such as calcium deficiency, mildew or stunted growth and development, so adequate watering is an essential part of their care.