General Weekly Guidelines (Seattle climate):
| Plant Type | Water Needed | How Often | Watering Time with Drip |
|---|---|---|---|
| Small Shrubs (2–4 ft) | 5–10 gallons/week | Once or twice/week | 1–2 hours with 1 GPH emitters |
| Medium Shrubs (4–6 ft) | 10–15 gallons/week | Once/week | 2–3 hours with 2 GPH emitters |
| Small Trees (newly planted) | 10–20 gallons/week | Once/week | 3–4 hours with 2 GPH emitters |
| Established Trees (6+ ft) | 20–50 gallons/week | Once/week or biweekly | 4–6 hours with multiple emitters |
What Type of Emitters or Drip Line?
For Shrubs:
- Use drip emitters (1 or 2 gallons per hour)
- Or use inline drip tubing (0.5 GPH spaced every 12″ or 18″)
- One or two emitters per shrub is usually enough, depending on size
For Trees:
- Use 2 GPH emitters
- Place 2 to 4 emitters in a circle near the dripline (edge of canopy, not near the trunk)
- Or run a loop of dripline around the base with multiple emitters
How Long Should I Run the Drip System?
That depends on the emitter rate. Here’s the math:
Example:
- 2 GPH emitter × 2 hours = 4 gallons
- If a shrub needs 8 gallons, that’s 2 emitters running for 2 hours, or 1 emitter for 4 hours.
So you’re not watering every day—you’re watering deep once or twice a week, depending on the plant and season.
Seattle-Specific Tips
- Clay soil? Water slower and longer. The soil holds moisture but drains slower.
- Sandy or loose soil? Water a little more often.
- Adjust watering based on season—cut back in spring and fall, increase in summer dry spells.
- Always use a filter and pressure regulator to prevent clogging and blowouts.
Want Help Designing or Upgrading Your Drip System?
We design and install efficient drip systems for landscapes all around Seattle—especially for yards with native plants, pollinator gardens, and edible landscapes. Whether you need a basic shrub loop or a full tree zone with smart controls, we’ve got the tools and the know-how.
Lee’s General Landscaping – Seattle, WA
Efficient irrigation, clean yards, and no wasted water.
Call or text Mr. Lee today for a drip system check-up or custom install.