The right way to water

 HOW DOES YOUR GARDEN GROW

By Kit Flynn
Columnist

When I first started to garden, I would haul out the sprinkler as I believed in the necessity of watering the whole plant, essentially giving it a bath. Then I took a course on (very) basic botany at Duke Gardens that radically changed how I watered plants. To understand watering, it’s essential to know the basics of how a plant functions.

Different parts of the plants perform different roles. Obtaining moisture from their environs in the soil is the job of the roots, while the leaves through photosynthesis, provide nutrients for the roots. Remember that plants without roots cannot survive.

The stem resembles a two-lane highway, with the nutrients obtained through photosynthesis traveling downward while the water defies gravity by flowing upwards to hydrate the leaves.

My apologies to any botanists reading this; I’m condensing what is probably a semester’s work into two sentences.

If you keep this in mind, you will realize that the roots require watering, not the leaves, as the leaves cannot push the water down to hydrate the roots—that is not their job. Now, we must ponder how to get water to those roots effectively.

The best way to hydrate the roots efficiently is to place the hose near the roots, allowing water to dribble out slowly for several hours. Why so long? A short watering encourages shallow roots, whereas a deep watering boosts deep roots. Why is this of value? Deep roots have a better chance of finding water than shallow roots as it’s the top of the soil that dries out first during our long, hot humid summers.

There are also soaking hoses that provide slow watering. These are convenient for traditional rose gardens, consisting of two rows of plantings, but I have not found them useful in a diverse garden such as mine.

If you do not have the time or inclination to provide slow watering (I have been known to forget to turn off the hose), gently water the root area with a hose in hand. If you have well-draining soil, the water may go somewhat deeply.

The key to effective watering is “well-draining soil.” Here, we have to understand the difference between clay and sandy soils. Clay soils are made up of small particles of soil, whereas sandy soils contain larger ones. Clay soils will retain water longer than sandy soils, as the large sandy particles allow the water to slosh through quickly. Both of these soils have their pluses and minuses.

Because most of us have clay soils, let’s concentrate on those pluses and minuses. Clay retains water, a positive aspect when rain is scarce. However, roots need oxygen if they are to survive. Consequently, they will drown if the water cannot seep through clay’s fine particles. This is particularly deadly in the winter when we can experience a surplus of rain. The answer is to develop a loamy soil that is well-draining.

How do you determine if your soil is well-draining? Go out to inspect the garden after a good, soaking rain. Do you see puddles? That’s an indication that your soil requires amendment.

Compost is called the gardener’s gold. Mix compost in with the soil and then cover it with a good organic mulch such as pine bark nuggets. Gradually the mulch will erode, thereby adding organic matter to the soil. Stone mulches, while looking attractive, add nothing to the soil.

Now the right way to water is to supply the roots with water. If you have the patience (and a good timer), by all means use the soaking hose method. If your garden is like mine, too diverse to handle that method effectively, hand water gently those plants that require regular soaking. During their first year, I always water the new plants that haven’t had the time to establish a sound root system.

Try not to water the leaves as this (1) wastes water and (2) promotes disease. Roses, for example, are susceptible to black spot, a fungus found in our soils. Water on its leaves simply promotes the development of this fungal disease. No, you do not have to get out the hair dryer to dry off the wet leaves after a good rain shower but try to refrain from getting water on the leaves when watering.

If you use a sprinkler system, employ it in the morning, thereby giving the leaves a chance to dry off quickly during the day. If you use the system in the evening, the cooling night temperatures and lack of sun will provide a moist environment that encourages disease.

Now, when we have a drought, we all (if we’re conscientious gardeners) want to nurture our plants through this difficult time. Do not reach for the fertilizer. This will either burn the roots—surely not optimal when they are already struggling—or encourage them to grow under unsustainable conditions.

Roses are heavy feeders, so I normally give them a round of fertilizer after their first bloom, usually sometime in early June. Because this past June was excessively dry, I withheld their feeding. I have too many roses scattered throughout the garden to individually deep water them after fertilization. It’s far better to have them go into light dormancy to get them through our summer droughts.

Droughts occur in North Carolina, creating problems for gardeners. Solutions include careful watering and conserving water, a finite resource. Also, remember that in North Carolina, rain will eventually arrive. In the meantime, you can always join other gardeners by wringing your hands over a lack of rain.

This reporter can be reached at Info@TheLocalReporter.press