How Much Water Do Snapdragons Need?

Soil Moisture Qualities

• Planting snapdragons in loam soil that drains well ensures the plants receive enough moisture without the soil becoming too soggy. Soggy soil encourages root rot, which kills both young and established snapdragon plants. Low-lying beds and beds where water collects after rainfall become too soggy for snapdragons. Working compost into the bed before planting may improve drainage.

Irrigation Amounts

• Snapdragons grow best when provided with an inch of water a week from irrigation or rainfall. An inch of water generally moistens the top 6 inches of soil in a bed. While plants generally require only an inch of water, hot weather and quick-draining soils may require more water. Feeling the soil and watering enough to keep the top 6-inches moistened but not soggy provides a better measure that the plants are receiving sufficient moisture.

Watering Methods

• Watering deeply once a week allows the moisture to penetrate more into the soil. Frequent shallow watering only wet the soil's surface, so that moisture doesn't penetrate to the root zone. Rust disease affects snapdragons when the foliage is left wet, usually from overhead watering. Irrigating at the base of the plants in the morning prevents the foliage from becoming moist and ensures any moisture that splashes onto the leaves quickly dries.

Mulch

• Mulch prevents moisture from evaporating too quickly in the soil. Mulch also suppresses weeds that compete with snapdragons for soil moisture. Mulch applied to a depth of 2 inches helps retain moisture and prevents weeds without damaging the snapdragons. The mulch also prevents soil from splashing onto the lower leaves of the snapdragons, which helps prevent soil-borne diseases.