Grow For it: Cool, clear water
By Barbara Finley
UCCE Master Gardener of El Dorado County
So, here we are at the end of summer and you have been diligently saving water, or so you hope. Some of us stumble along thinking we are doing so very well; then we receive the first summer season water bill and are told we have used more water than our neighbors! What do you know about water? About how it functions in the garden? How it keeps a plant alive? How much does that petunia or that rosebush or that tomato plant really need?
Time to learn: 90 percent of a plant is water. Water is needed for photosynthesis, the process by which plants convert light energy into chemical energy. How does water get into the plant? Most enters through the roots. For plants to survive and perform their function, the watering you do needs to go deep.
Another key element in nurturing plants is the soil structure. There are four types of soil: sand, loamy sand, loamy clay and clay. Each has different needs. Sandy soils hold less water and need to be watered more frequently. Clay soil holds more water so it takes in water more slowly and needs to be watered less frequently. Knowing your soil is important in order to set your watering schedule.
We are frequently under water restrictions and it is critical to water effectively. Two tendencies of many homeowners — over-watering and using improper watering techniques. The speed of water delivery is very crucial. The way water is being dispersed also plays a role. Is the irrigation system drip or overhead? How hot is it? How windy? How humid? There is also a desirable depth to water for different plants:
- Leafy and annual plants: 6 inches to 1 foot
- Small shrubs, cool-season turf grass, corn, tomatoes: 1 to 2 feet
- Large shrubs, trees, warm-season turf grass: 1.5 to 5 feet
Understanding how roots obtain water from the soil is an important component in understanding proper watering technique. To have a healthy plant, healthy roots are necessary. Plant roots do not live in soil, but rather grow in air pockets between the soil particles. When plants are watered, water fills the air pockets, pushing oxygen into the plants. As the water drains down, air follows it and the cycle continues. If a plant receives too much water, the roots remain waterlogged, and growth will suffer. If a plant doesn’t get enough water, the plant may undergo water stress and stop growing. The optimum soil is one with lots of open pores and enough organic matter to hold water, achieved by mixing in loads of compost.
Clay soil has very tightly bound particles. Water drains through it very slowly; water needs to be applied in a very slow manner. The clay soil will dry out very slowly, and can be watered infrequently. Sandy soil is just the opposite. Water goes it through rapidly and needs frequent watering. Loamy soil is preferable as it combines aspects of both sand and clay.
How does this affect our watering?
It really goes back to what you are or want to be growing, what the season is, what your soil is like and what the watering guidelines are for your area, Drought is a common occurrence in our area of Northern California. Using smart watering procedures becomes something we need to follow at all time.
UCCE Master Gardeners of El Dorado County are available to answer home gardening questions at local farmers markets and in their office at 311 Fair Lane in Placerville from Tuesday through Friday, 9 a.m. to noon. Walk-ins are welcome, or call (530) 621-5512. For more information about our public education classes and activities, go to our Master Gardener website at ucanr.edu/sites/EDC_Master_Gardeners/. Sign up to receive our online notices and e-newsletter at ucanr.edu/mgenews/. You can also find us on Facebook.