How Much to Water Your Garden?
Vegetables are made up of about 90% water and because of this require sufficient moisture to grow. Water is also important because it allows plants to take nutrients from the soil. The minerals in the soil dissolve in thse moisture so that the roots of the plant can absorb them to help the plant grow. If your soil doesn’t have enough moisture it can accumulate high amounts of harmful salts, rendering it inhabitable.
Amount of water:
Soil receives water naturally through rainfall or by irrigation.
During heavy rain, gravity pulls the water down into the soil
filling up all the pore spaces between soil particles. This is
an ideal condition allowing plants to grow to their fullest without
stress due to a lack of moisture. The soil will continue to
lose water through two mechanisms. The plants will gradually soak up
moisture from the soil through their roots to obtain nutrients.
The soil also loses water through evaporation at the surface of the
soil, which is one of the main reasons for mulching.
A typical garden requires at least an inch of water a week, which
should leave the soil soaked about 5-6 inches deep. Keep in
mind that sandy soils, which have poor water retention, may require
significantly more water. It may be helpful to put a rain
gauge or a coffee can in the garden to keep track of how much
rainfall your garden receives each week. If ten days or more
go by without rainfall, it’s time to get out the gardening hose.
Too little water can cause plants to develop shallow roots that can
become scorched in hot dry weather, often killing the plant.
So how much water does my garden need?
The answer to this question is a lot! While an inch of
rainfall doesn’t sound like much, an inch of rainfall covering a
garden that is 20’ x 10’ (200 square feet) is equivalent to
approximately 125 gallons of water. For a rough estimate of
how much water your garden requires, use 5 gallons of water per 8
square feet.
Due to gravity, water has a tendency to flow downward into the soil.
The better the soil structure, (particle size and pore space), the
easier it will be for the water to move through the soil.
Heavy clay soils have tiny clay particles that clog quickly causing
water to runoff without penetrating. Sandy soils lose water
rapidly because the water tends to flow through the large pore
spaces with nothing to hold on to. Both types of soils can be
improved in their ability to retain water by adding generous
quantities of organic matter annually. When organic matter is
added to clay soil it acts like a glue, making larger particles out
of the small particles and thus increasing pore space for added
water retention. In sandy soils organic matter fills the large
pore spaces and enables the soil to retain more water.
When to water:
There are two times during the growing season when it is critical
that your garden receives adequate moisture: When the seeds are
germinating and just prior to harvest. Wilting is an
indication that your plants aren’t getting enough moisture from the
soil. When a plant begins to wilt it needs water immediately.
Ensuring your plants receive sufficient amounts of water each week
will enable the roots of the plants to grow deep where they can
access additional moisture. Deep roots also make for a healthy
and sturdy plant that is less likely to be damaged by wind.
You can water your vegetable plants at any time. Contrary to
common belief, the leaves will not scorch from the sun if you water
them in the heat of the day, although you will lose some moisture
through evaporation. If time permits, it’s best to water
plants is in the morning, as they are already wet from the morning
dew. This allows them to dry off as they would naturally, and
keeps the time they are wet to a minimum. Some plants are more
susceptible to disease if left wet for prolonged periods of time, as
could be the case if watered late in the evening.
How to water:
The most water conservative method of irrigation is a soil soaker system, which consists of a special hose that allows water to seep into the soil with minimal runoff. Sprinklers are easier and cheaper, and can be set up to cover wide areas. Those who are extremely conservative with their water can collect rainwater from their gutters in barrels to use as a water source for the garden.
