Water is essential for plants to absorb nutrients from the soil. The weekly water requirements of plants varies by temperature and by type of soil. At temperatures of 70°-75°F (21-24 C), plants use 0.15″-0.20″ (0.4-0.5 cm) of water per day, or 1.05″-1.40″ (2.7-3.6 cm) per week. At temperatures of 80°-90°F (27-32 C), plants use 0.25″-0.35″ (0.64-0.9 cm) of water per day, or 1.75″-2.45″ (4.44-6.0 cm) per week. Use the lower rates for clay soil and the higher rates for sandy soil. For every day that temperatures exceed 90°F, add 0.25″ (0.64 cm) of water per day.
Water infiltrates the soil more quickly on lighter soils than on heavier soils. Whether you use a drip irrigation system (greatly preferred to minimize both atmospheric water loss and fungal leaf diseases) or an overhead watering system, adjust the flow rate as follows:
- Sand 2.0″ (4.9 cm) per hour (Needs a faster drip rate)
- Sandy Loam 1.8″ (4.6 cm) per hour
- Silt and Clay 0.5″ (1.3 cm) per hour
- Clay 0.2″ (0.5 cm) per hour (Needs a slow rate or else water will puddle)
Since watering the lawn or garden plants can be expensive, a rain gauge is a useful tool for seeing how much water needs to be supplied to make up for any rain deficiencies during the week. The Jumbo EZ Read Rain Gauge is my favorite tool for determining how much extra water is required each week. Some hardware stores may carry this item, or else search the internet for a preferred supplier.