Greenhouses create a unique irrigation challenge—higher temperatures, no rainfall, dense plant spacing, and the need for precise moisture control. The key differences from outdoor drip systems are higher humidity management, fertigation integration, and tighter emitter spacing. Here’s the related complete guide to greenhouse drip irrigation.
What Drip System Works Best in a Greenhouse?
For greenhouse benches and tables, use ¼-inch micro tubing with individual adjustable drip stakes at each plant pot. 00 per plant. 5 GPH pressure-compensating emitters spaced 12 inches apart.
50 per foot. 5-2 GPH each). Most greenhouse drip systems operate at 15-25 PSI—use a pressure regulator with a gauge ($15-25). A 150-mesh disc filter is essential for greenhouses using rainwater collection, which is common in greenhouse operations. support/drip-irrigation-complete-guide/).
How Do You Design Drip Layout for Greenhouse Beds?
Greenhouse beds are typically arranged in long, narrow rows. Run a ½-inch main header line along the greenhouse spine, then branch into ¼-inch micro lines for each row or bench. Space emitters 6-12 inches apart for dense plantings like lettuce, herbs, or starts.
For larger greenhouse plants like tomatoes, peppers, or cucumbers, space 12-18 inches with 1 GPH emitters. Consider separate zones for benches vs ground beds—benches dry out faster and need shorter, more frequent cycles (10-15 minutes daily) while ground beds run longer (20-30 minutes every 2-3 days). A dual-zone timer ($30-60) handles both schedules. support/how-to-design-an-irrigation-system-for-your-lawn-or-garden-complete-guide/) covers layout strategies.
How Do You Prevent Algae and Disease in Greenhouse Drip Systems?
Greenhouses have higher humidity, which promotes algae growth inside drip lines and on soil surfaces. Use opaque (black) drip tubing—clear or translucent tubing promotes algae growth inside the line. Install a backflow preventer ($15-30) at the water source—it’s required by code in most areas for greenhouse irrigation to prevent fertilizer or algae from contaminating the water supply.
Flush greenhouse drip lines monthly (more often than outdoor systems) to prevent algae buildup. Use a 150-mesh filter and clean it every 2 weeks during peak growing season. support/fertigation-101-how-to-fertilize-through-drip-irrigation-systems/) for injector setup and cleaning.
How Much Water Do Greenhouse Plants Need?
5 inches of water per week—less than outdoor plants because there’s no rainfall contribution and lower wind evaporation. But the frequency is higher: in summer, greenhouse beds need watering every 1-2 days, and benches may need daily watering. Run drip cycles for 10-15 minutes on benches and 20-30 minutes on ground beds.
A humidity sensor ($25-50) or electronic moisture meter helps dial in the schedule. In winter, reduce watering by 50-75%—greenhouse plants grow slower and use less water in low-light conditions. support/irrigation-timer-programming-4-step-guide-for-any-controller/) covers greenhouse-specific scheduling.
How Much Does a Greenhouse Drip System Cost?
For a 10×12 hobby greenhouse with 200 sq ft of bench space: $30-40 for 100 ft of ½-inch header tubing, $25-40 for 50 adjustable drip stakes with ¼-inch micro tubing, $15-25 for a pressure regulator with gauge, $12-20 for a 150-mesh disc filter, $10-15 for backflow preventer, and $25-40 for a dual-zone timer. Total: $117-180. For a 500 sq ft greenhouse with ground beds: expect $200-350.
The system pays for itself in reduced water waste (greenhouse drip uses 40-60% less water than hand watering) and improved plant health. For a full cost comparison, see irrigation system costs.
References
- EPA WaterSense (U.S. Environmental Protection Agency)
- Irrigation Association (Irrigation Association)
- Penn State Extension – Drip Irrigation (Penn State University)