Many, many problems are caused for houseplants and garden plants by common watering mistakes. These include under watering, over watering, watering at the wrong time, improper watering and watering on a schedule. All of these can lead to plant diseases especially those caused by fungus. They can aid in the spread of plant disease and the leaching of nutrients in container plants. I can't tell you how many times I have gone by a house with the sprinkler going full force while it was raining. What an absolute waste of resources! Sprinklers by their design waste water so an eco-friendly home garden doesn't use sprinklers to begin with. I've talked about watering problems before so here are a few more comments on the subject.
- under watering - Under watering causes the soil to dry out enough that the plant can wither and die. Unless a plant's care stipulates it must dry fully between waterings, do not allow plants to dry out. Avoid this problem especially in indoor or outdoor container plants by using self-watering planters, watering globes or gravity fed self-watering system.
- over watering - Over watering is a very, very common problem both indoors and outdoors because the home gardener fails to realize the needs of the plant. Outdoors, overwatering can occur naturally (eg. a week of storms with heavy rains) or by improper watering (eg. watering too much or watering when it is raining). Over watering leaches nutrients from the soil and causes problems for plants that don't like their feet wet (eg. tomatoes). It can lead to plant diseases caused by a variety of fungus and cause damping off in seedlings. Avoid over watering by using self-watering planters, watering globes or a gravity fed self-watering system.
- watering at the incorrect time - It is important to water plants as they need the water. Outdoor plants should be watered in the morning after the dew has burned off, before the heat of the day (1 PM - 4 PM) and early enough they have a chance to dry a bit before the evening hours. Always water during daylight hours when watering indoors to allow the soil to dry a bit before lights go out.
- improper watering - Plants should be watered at the soil level without getting the foliage wet. Wet foliage aids in the spread of plant fungal diseases and cause sunburn on both indoor and outdoor plants. Indoor plants can benefit from a shower to clean off dust on the leaves but should be allowed to dry fully before returning the plant to its location. Outdoor plants get sufficient rain to wash off any dust although if you have a container plant in a location where rain will not reach it, a short shower from a watering can can be beneficial.
- watering on a schedule - Home gardeners make the mistake of watering on a schedule rather than on the basis of whether or not the plant needs watering. Watering should always be tailored to the plant's needs. If in doubt or on vacation use self-watering planters or water globes both indoors and outdoors. Avoid using timed watering devices (eg. timed sprinkler systems) for watering your plants outdoors as this can result in over watering if it happens to rain.