One of the most logical questions we get here at the store is “how often should I water my plants?” This is a seemingly simple question however the answer is generally far more complex. Given our current drought conditions, this seemed an ideal time to examine the 3 W’s of watering: Why, When and Where.
Why do we water?
In 4th grade science class we all learned that plants are living things that require water to survive however, the confusion becomes apparent when determining the differing needs of individual plants and with the variations of those plant locations. Plant type, size and age will also affect watering requirements as will weather/climatic conditions. It is vital that plants are located in areas that match all their environmental needs and that plants are grouped accordingly. Good irrigation can’t make up for poor plant placement.
Young plants are like children in that they require additional and more frequent care to thrive. A common mistake for gardeners is to assume that once a plant makes it through a winter that supplemental irrigation is no longer necessary. During periods of drought, like we are now experiencing, the range of plants that will require supplemental irrigation expands in direct proportion to the severity of the drought, the water needs of the plant and the location of the plants in question. The more shallow the root systems of a plant are, the more quickly they will dry out, so annual and perennial flowers will usually dry out more quickly than trees and shrubs. Soil conditioned with organic matter holds more moisture (requiring less irrigation) than sandy/gravel soils or clay based soils that do not readily absorb/retain moisture.
When is it most ideal to water?
As simple as the answer sounds it isn’t… whenever the plants are dry is when they should be watered. Weekly for newly planted trees, twice a week for shrubs and twice a week for flower and vegetable gardens as well as newly growing lawns. Ideally, we would like to water in the morning so leaf surfaces can dry out in the light of the day thus avoiding one of the major causes of leaf diseases. Deep watering develops deep root systems so too much water is not as much a concern as is watering too often can be. Water needs to be delivered to the plant roots that are not necessarily located at the soil surface so what your eyes see isn’t necessarily an indication of what your plants may be experiencing. Soil may be dry at the surface and moist 2” below while a little rain may superficially wet the surface only to have dry soil 2” below. The only way to be sure is to scratch the soil down to where the plant roots are to determine the moisture level where it is required. Newly planted trees and shrubs may require 5-20 gallons of water per irrigation to properly deliver water to the entire root system of a plant. Overhead sprinklers may need to run for 30-60 minutes to moisten the top 12” of soil in flower and garden beds. Less frequent, heavier watering is more effective than light daily sprinkles. Once soils become dry even more water may be needed to penetrate dry, caked soils.
Where do we water?
Water applied to the soil surface (not on plant foliage) is ideal however not practical in many situations. Drip tape and soaker hoses are very efficient in some situations but hoses and sprinklers are more commonly utilized. Sprinkler towers are great for covering large areas while a good watering wand is ideal for watering pots and baskets. Kink free hoses are expensive but are far less frustrating than cheaper options. Sprinkling/watering cans are less effective but very helpful when applying/measuring liquid fertilizers. Gator bags are water bladders ideal for irrigating trees that are not accessible directly by hose. Another option for watering trees is drilling small holes in the base of 5 gallon bucket developing a trickle of water that slowly penetrates deeply to tree roots.
In the end, you need to know your irrigation inclinations to determine what type of waterer you are. Are you a neglector who forgets to water plants until it is too late or are you a nurturer who is more likely to water a plant to death? Either way, when we are faced with hotter and drier than average conditions, how you address the care and watering of your plants will greatly determine their future success.
Now go outside and have fun in the dirt!