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(515) 294-9915

3/12/01

Contacts:
Cindy Haynes, Horticulture Extension, (515) 294-4006, chaynes@iastate.edu
Elaine Edwards, Continuing Education and Communication Services, (515) 294-5168, eedwards@iastate.edu

Yard and Garden Column for the Week Beginning March 16

Watering 101 -- A Short Course

By Megan McConnell
Horticulture communications intern
Iowa State University Extension

Buried deep in the pages of gardening manuals between maintaining razzle-dazzle roses and creating islands of brilliant color lies the overlooked art of watering. Receiving little of the attention it deserves, watering is regarded as a natural talent that every gardener has at his or her disposal.

Contrary to popular belief, knowing when and how to water is not innate, but instead must be learned through education and regular practice.

When to Water
The first topic in Watering 101 is learning when to water. Commercial growers often use tensiometers or soil moisture blocks to determine if their crops need watering. For home gardeners, however, visual inspections of the plants and soil are often the best way to determine if an area needs to be watered.

Let your plants tell you when to water. Plants can tell us about their growing conditions by the way they hold their stems, leaves and flowers. Observe your garden in the early morning, before scorching sun has hit and when plants are at their peak. The heat of the day will commonly cause plants to wilt slightly, but they will regain their strength and stand tall by nightfall. A plant showing signs of stress through limp leaves and bending stems in the morning could use a dose of water to sustain it through the hottest period of the day.

The soil also can aid you in making watering decisions. Remember that each plant has different water requirements. For example, fernleaf yarrow (Achillea millifolium) can tolerate arid conditions, while impatiens (Impatiens wallerana) requires more moist soil conditions. Due to these differing water demands, the level of soil moisture affects each plant individually. To check soil moisture, dig 6 to 8-inches below the surface. If the soil at this level is visibly moist, there is no need to water. If the soil is on the dry side and plants are showing signs of water stress, a deep watering will be appreciated.

The next lesson in Watering 101 is a discussion of proper watering procedures. Overfed and over watered plants can quickly become garden junkies, demanding large quantities of water to maintain their lush, overgrown foliage. Avoid junkies by watering lawns and gardens deeply and infrequently. For most flower, vegetable and fruit gardens, a deep watering once a week is adequate. Ideally, the top 8 to 12 inches of soil should be moistened. Deep, infrequent watering promotes the development of extensive root systems. Deep-rooted plants are able to survive hot, dry weather quite well. Some drawbacks to frequent, shallow watering include increased disease problems and higher water bills. Frequent irrigation also wastes one of our precious natural resources -- water.

How to Water
There are several methods of providing water-deprived plants with the moisture they require. For this lesson in Watering 101 we will go to the outdoor lab to examine four popular methods of watering &endash; sprinklers, soaker hoses, watering cans or hand watering with a hose.

Sprinklers can be used to water large areas such as lawns or low growing annual beds. The most commonly used sprinkler is the oscillating sprinkler. An oscillating sprinkler consists of a horizontal tube with several holes along it. The oscillating sprinkler can spray in a single direction or in a circle. Another type of sprinkler is the traveling sprinkler, which moves along a length of cable or cord and is commonly used on lawns.

When watering with a sprinkler, early morning is the best time to water. Morning applications allow the water to soak into the ground and reduce water lost through evaporation. Also, the plant foliage will dry quickly after morning watering. Watering at midday is less efficient as considerable amounts of water are lost through evaporation. Disease problems may increase if plants are watered in the evening. Sprinklers are commonly faulted for their uneven water distribution and subsequent water loss.

Soaker or porous hoses are more efficient than sprinklers for flower and vegetable gardens. Soaker hoses contain thousands of tiny holes allowing water to seep through. By delivering water directly to the base of plants, soaker hoses minimize runoff and evaporation. Soaker hoses are flexible and can easily be wound down rows and around plants.

Watering cans are another way to provide water to your plants. Watering cans are an excellent way to water hanging baskets, window boxes and pots. Be sure to take your time when watering pots. Allow the water to seep slowly into the soil.

Hand watering with a hose is one of the most inefficient ways to water gardens. Hand watering often leads to run-off as water is applied faster than it can soak in to the soil. For gardeners who choose to hand water with a hose, there are a variety of nozzles to distribute water in a fine mist or a dense stream. A hose can be cumbersome when pulling it from flowerbed to flowerbed. Corner protectors will help hoses skirt planting areas and a reel-style hose caddy will allow you to quickly roll the hose up after the watering is finished.

Our short course on efficient watering practices in the garden is nearly over. This might have served as a refresher course for water savvy gardeners or an in-depth lesson for those new to gardening. Experienced gardener or novice, the test is the same for both groups &endash; this year's growing season is your exam.

Watering Tips
Water deeply, but infrequently
Water in the early morning to reduce evaporation
Spread a fine layer of mulch over gardens to conserve soil moisture
Avoid wetting the plant foliage when watering
Group plants with similar water demands together

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ml: isugarden


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