For many gardeners, knowing how much to water can be difficult. There are a lot of factors that determine how much to water in your garden. Some of these factors differ from place to
place. For example, type of existing soil conditions, levels of sun/shade, drainage, whether you water by hand (with a garden hose) or by irrigation system. The ideal conditions is to
have a well balanced program for watering. Learning the type of soil conditions in your garden is key.
TIP:How to tell if you are over-watering.
Look at the leaves on your deciduous trees, especially in your most recently planted gardens. As a general rule of thumb, if the an individual leaf seems curled at the edges towards
the back of the leaf, it is probably waterlogged, and you should cut back on your watering. Another sign of overwatering on most plants is a discolouration (lightening of normal colour
or yellowing) of the leaves.
TIP:How to tell if you are under-watering.
Look at the leaves on your deciduous trees. The individual leaf will be wilting towards the front of the leaf, if it is needing more water. Some curling or browning at the edges of the
leaf may also be occuring.
For Clay Soil
Water longer but less frequently if you have clay soil, allowing runoff to absorb before continuing. In clay soil, if you water for longer periods, the water will remain in the ground
for a longer period of time. Even if the top of your garden soil may look dry, the soil underneath may be retaining water. Over-watering can result in your plants becoming water logged
and root rot may occur. Plants do need water to survive but also they need the process of drying out so that the root system must work and grow deeper into the ground to source water.
Too much water will allow the root system to become stagnant and lazy and this is when rotting and stunting of growth can occur.
For Sandy Soil
Water for a shorter period of time, but more often for sandy soil because the water will soak in quickly, move past the root system and down into the water table.
In a clay based soil, if you apply 1 inch of water over a given area and allow it to soak in, it will wet the top four to five inches of soil. In sandy soil, that same 1 inch of water
will wet the top 12 inches of soil. Most plant roots are found in the top 6 inches of soil. If your sprinkler system is not on a pre-measured timer, simply place a used soup can under
your sprinkler system and turn off the system when the soup can is filled with 1 inch of water. This will measure the amount of water being applied to your garden
TIP: This Do-It-Yourself Test will evaluate your water drainage (the ability of water to move through the soil) moving very slowly through clay and very quickly through sand.
- Dig several holes (1' deep by 2'wide) in various places in and around your garden. Just set that soil aside, so you can re-fill the holes after the test.
- Cover the holes with sheets of plastic to let the soil dry out.
- Once the soil is dry, fill each hole to the top of the water and time how long it takes for the water to completely drain.
The ideal time is between 10-30 minutes.
- If the water drains in less than 10 minutes, the soil will tend to dry out too quickly in the summer.
- If it takes 30 minutes to 4 hours to drain, you can still grow most plants but will have to water slowly to avoid runoff and to allow the water to soak in deeply.
- If your soil takes longer than 4 hours to drain, you may have a drainage problem. In sandy soil, dig down a foot or two to see whether a hard layer is blocking water movement. If
so, break it up. If your soil is dense clay, raise the whole bed to get your plants up out of the soggy soil and into well-drained, elevated soil.
Here are ExperTrees’ general guidelines for watering.
- For planters and pots in sunny locations water every day
- For established lawns water every 3 days
- For established gardens with a clay based soil water every 3 days
- For established gardens with sandy soil water every other day
- For newly planted trees in clay soil water every 3 days
- For newly planted trees in sandy soil water every other day
- For established trees in either sandy or clay soil water every 10 days
- For newly laid sod or grass seed water thoroughly every day for 14 days straight
- For newly planted annuals and perennials water every day.
- For established annuals and perennials water every 3 days
These are general rules of thumb, they can differ from property to property. Monitor the plants appearance and water accordingly, depending on weather, temperature, amount of sunlight,
soil conditions, drainage and type of watering system you are using. For example, even established gardens, trees, annuals and perennials may need more water during hot, sunny weather.
ExperTrees has had success following these guidelines.
You can not change the soil conditions that are prevalent in your property. Just because you may add organic material or triple mix to a garden, your base soil will always remain the
same so it is very important for gardeners to know the base soil for watering and drainage.
TIP: When the property was originally graded, it was designed for water to be removed away from the property to catch-basins or drainage areas. When constructing a garden bed,
your base soil and watering/drainage requirements must be considered. For example, if you excavate the soil too deeply for your garden bed in a clay-based property, you are essentially
changing the grade making that garden bed the lowest point and naturally the water will flow into it causing the garden to be constantly water logged, which causes undue stress and eventually
death to the plants. When constructing a garden bed in a clay-based property, remove only the sod and 2 inches of the clay. Elevate your garden bed with organic material or triple mix
to allow for better drainage.