Nursery & Greenhouse Well Systems: The Complete Guide for 2026

For nurseries and greenhouses, water quality isn't just about human health — it directly impacts plant health, growth rates, and your bottom line. The wrong water chemistry can stunt growth, cause leaf burn, clog irrigation systems, and kill sensitive crops. Getting your well water right is essential for any commercial plant production operation.

At Southern California Well Service, we work with nurseries, greenhouses, and landscape operations throughout San Diego and Riverside Counties. We understand that your water needs are different from residential or even standard commercial customers — and that plant losses from water problems can be devastating.

Water Quality Parameters That Matter for Plants

Drinking water standards are designed for humans. Plants have different sensitivities. Here are the key parameters nurseries must monitor:

Electrical Conductivity (EC) / Total Dissolved Solids (TDS)

EC measures total salts in water and is the single most important parameter for most nurseries:

• <0.5 dS/m (320 ppm TDS): Excellent — suitable for all plants including sensitive species
• 0.5-1.0 dS/m (320-640 ppm): Good — suitable for most nursery crops
• 1.0-2.0 dS/m (640-1,280 ppm): Moderate — salt-sensitive plants may show stress
• >2.0 dS/m (>1,280 ppm): High — requires treatment or salt-tolerant crops only

Note: When you add fertilizer, EC increases further. If your base water is already 1.0 dS/m and your fertilizer adds another 1.5 dS/m, your plants receive 2.5 dS/m — potentially damaging.

pH

Water pH affects nutrient availability and can damage sensitive foliage:

• 5.5-6.5: Ideal for most nursery crops
• 6.5-7.5: Acceptable for many plants
• >7.5: Can cause iron and manganese deficiency; may need acid injection
• <5.5: Rare in groundwater; can cause aluminum toxicity

Alkalinity (Bicarbonates/Carbonates)

High alkalinity buffers pH upward over time, even in acidic growing media:

• <100 ppm: Low — no concerns
• 100-200 ppm: Moderate — monitor media pH
• >200 ppm: High — may need acid injection to neutralize

Specific Ion Toxicities

Some ions are toxic to sensitive plants even at low concentrations:

Ion	Safe Level	Problem Level	Symptoms
Sodium (Na)	<50 ppm	>100 ppm	Leaf burn, poor growth
Chloride (Cl)	<70 ppm	>140 ppm	Leaf tip/margin burn
Boron (B)	<0.5 ppm	>1.0 ppm	Leaf tip necrosis
Fluoride (F)	<0.5 ppm	>1.0 ppm	Leaf tip burn on sensitive species

Sensitive crops: Azaleas, camellias, gardenias, blueberries, citrus, tropical foliage, and many greenhouse ornamentals are particularly sensitive to chloride, sodium, and fluoride.

Iron and Manganese

Unlike for drinking water where iron is primarily an aesthetic issue, in nurseries:

• Iron >1 ppm: Can clog drip emitters and mist nozzles
• Iron bacteria: Forms slime that plugs irrigation systems
• Staining: Orange/brown residue on foliage, benches, and structures

Learn more: Iron and Manganese Treatment

Water Testing for Nurseries

Standard drinking water tests don't cover all parameters nurseries need. Request a horticultural water analysis that includes:

Basic Panel (Minimum)

• EC / TDS
• pH
• Alkalinity (bicarbonates, carbonates)
• Hardness (calcium, magnesium)
• Sodium, chloride
• Iron, manganese

Complete Panel (Recommended)

Add to the basic panel:

• Boron
• Fluoride
• Sulfate
• Nitrate (affects fertilizer calculations)
• Ammonium (if present, affects nitrogen management)
• SAR (Sodium Adsorption Ratio) for field nurseries

Testing Frequency

• Annual: Complete panel at minimum
• Quarterly: EC and pH if you notice variability
• After drilling/work: Complete panel before using modified well
• If problems appear: Immediate testing to diagnose

Water Treatment for Nursery Operations

Reverse Osmosis (RO)

RO removes nearly all dissolved minerals, producing nearly pure water. Used when:

• Source water EC is too high (>1.5 dS/m)
• Specific ion toxicities can't be addressed otherwise
• Growing highly sensitive crops (orchids, some tropicals)
• Need precise control over all nutrients

Considerations:

• Expensive to install ($10,000-$100,000+ depending on capacity)
• Wastes 20-50% of input water as brine
• Requires maintenance (membrane replacement, pretreatment)
• Produces water with no calcium/magnesium — must add back for plant health

Acid Injection

Lowers pH and neutralizes alkalinity. Most nurseries use:

• Sulfuric acid: Most common, adds sulfate (usually beneficial)
• Phosphoric acid: Adds phosphorus (nutrient), more expensive
• Citric acid: Organic option, biodegrades, most expensive
• Nitric acid: Adds nitrogen, requires careful handling

Injection systems cost $2,000-$15,000 installed. Acid is an ongoing expense ($500-$3,000/year depending on volume and alkalinity).

Iron/Manganese Removal

For nurseries with iron issues, options include:

• Settling pond: Aerate water, let iron precipitate, use clear water
• Oxidation + filtration: Air injection or chlorine followed by media filters
• Greensand or Birm filters: Oxidizing filter media

Iron removal is critical if you use drip irrigation — plugged emitters kill plants and cost time/money to replace.

Water Softening

Caution: Traditional salt-based water softeners replace calcium and magnesium with sodium. This is generally bad for plants — you're trading hardness for sodium toxicity.

If hardness is truly problematic (scale buildup, nutrient lockout), consider:

• RO instead of softening
• Potassium chloride regeneration (adds potassium instead of sodium)
• Template Assisted Crystallization (TAC) systems that don't add sodium

Irrigation System Design

Water Demand Calculations

Nursery water use varies dramatically by crop type, container size, and production method:

• Container nursery: 1-3 gallons per square foot of bench space per day
• Greenhouse vegetables: 0.1-0.3 gallons per plant per day
• Field nursery: 0.5-1.5 acre-inches per week during growing season
• Mist propagation: Very low volume but frequent cycles

Peak demand: Summer months may require 2-3x winter usage. Size your system for July, not January.

Well Sizing

For commercial nurseries:

• Small operation (1-2 acres): 20-50 GPM
• Medium operation (5-10 acres): 50-150 GPM
• Large operation (20+ acres): 200-500+ GPM or multiple wells

Include storage tanks to meet peak demand without oversizing the well.

Pressure Requirements

• Drip irrigation: 15-25 PSI at emitters
• Overhead sprinklers: 25-45 PSI depending on nozzles
• Mist systems: 40-80 PSI for fine droplets
• Boom systems: 40-60 PSI typically

A constant pressure system with VFD maintains optimal pressure as demand varies throughout the day.

Filtration

All nursery irrigation systems need filtration to protect emitters, nozzles, and plants:

• Sand media filters: Best for high sediment loads, algae, organic matter
• Disc/screen filters: Good for moderate sediment, lower cost
• Automatic backwash: Essential for commercial operations
• Mesh size: 150-200 mesh for drip, 80-100 mesh for sprinklers

Common Water Problems in San Diego Nurseries

Based on our experience with local nurseries:

High Salinity

Coastal and some inland wells can have elevated TDS. Solutions:

• Blend with rainwater or RO water
• Choose salt-tolerant crops
• Increase leaching fraction (apply extra water to flush salts)
• Install RO for sensitive production areas

High Alkalinity / pH

Common in our limestone-influenced aquifers. Solutions:

• Acid injection (most common)
• Use acidifying fertilizers
• Lower media pH with sulfur or acidifying amendments

Iron Bacteria

Creates slimy orange deposits that clog everything. Solutions:

• Chlorination at the well or storage tank
• UV treatment
• Regular system flushing and cleaning
• Oxidation and filtration

Variable Quality

Some wells show seasonal variation in water quality. Monitor regularly and adjust treatment as needed.

Recirculating and Recycling Water

Water conservation is increasingly important for California nurseries. Many operations now:

Capture and Reuse Runoff

• Collect drainage from container areas
• Direct to retention ponds
• Treat (filtration, UV, chlorination) and reuse

Benefits: Water savings, fertilizer savings, reduced environmental impact

Challenges: Disease transmission risk (treat before reuse), salt accumulation, algae management

Rainwater Harvesting

Rainwater is essentially distilled water — very low EC, near-neutral pH. Excellent for:

• Blending with high-EC well water
• Sensitive crops
• Propagation areas

Size storage for maximum benefit from infrequent Southern California rain events.

Regulatory Considerations

Groundwater Extraction

Large nurseries may face groundwater sustainability regulations:

• Well registration with local Groundwater Sustainability Agency
• Metering requirements
• Potential pumping fees
• Extraction limits in stressed basins

Runoff and Discharge

Nursery runoff containing fertilizers and pesticides is regulated:

• No direct discharge to waterways
• May need NPDES permit for stormwater
• Retention and recycling reduces regulatory burden

Employee Drinking Water

If employees drink water from your well, domestic water quality standards apply to at least some portion of your supply.