Vegetable Gardening - Handbook for Beginners
Chapter 2.5.
The ideal time to water is before mid-morning. This avoids water waste through evaporation, and enables foliage to dry by sunset, thus precluding disease development.
Fungal diseases thrive when temperatures remain between 70 and 80 degrees; they need only 2-4 hours of moist, warm conditions to develop.
Deep and infrequent watering is important. It is best to water just to the point of run-off, and water as frequently as needed to meet the shovel test (soil should be moist to the base of the shovel when inserted into the soil). Also, if water is running off, you are wasting water. Creating wide watering basins will help guide water to plant roots.
Drip irrigation is a system of applying water to the soil slowly so that waste is minimized. With sprinklers, there may be losses of water outside of the planting area, some runoff if application rates are too high, and evaporation loss to the air. Drip irrigation systems allow water to be emitted uniformly and slowly at the plant location so that essentially all of the water is placed in the root zone.
Most drip irrigation systems should utilize relatively inexpensive cartridge-type filters, as emitters or drip holes tend to become plugged with tiny particles or salts contained in the water supply. Drip irrigation devices range from simple perforated tubes and soaker hoses to sophisticated self cleaning individual emitters.
One inch of irrigated water will soak down to different depths, depending on how heavy your soil is: 12” deep in sandy soil, 9” deep in loamy soil, but only 3” deep in clay soil. Plant root zones generally reach from 2-12” down, but roots of larger plants like tomatoes may reach 3’ down.
Clay soil, because it is so compact, can be watered a little each day for two to three days to enable deep absorption.
- Overwatering is a frequent cause of plant death, since too much water will fill the soil’s pore spaces and drown the roots.
- Avoid walking in your garden after watering so that you do not compact the soil. Use stepping stones and straw or mulch paths. Never step into growing-area beds.
- To maintain plant health, overhead water once a week to keep leaves clean.
Two recycling tips:
- Recycle plastic bottles as drip-irrigation containers. Cut off their bottoms, put small holes in the cap, invert, bury, and add water and fertilizer.
- Bury 1-gallon- and 5-gallon-size planting containers almost completely to their rims for easy deep watering with a hose; add a shovelful of manure or compost for feeding every time you water.
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