Science · Plants, Natives & Crops
Phacelia
Phacelia provides flowering habitat for pollinators while capturing existing soil nitrogen and protecting the soil surface. It does not fix atmospheric nitrogen, and its establishment and biomass production depend on planting method, season, and moisture availability.
Profile
- Growth habit
- Upright annual with hairy stems and finely divided foliage.
- Height
- The California chart describes plants approximately 1–3 feet tall.
- Nitrogen
- Nitrogen scavenger, not a biological nitrogen fixer.
- Seeding depth
- The Iowa NRCS fact sheet lists approximately 0.25 inch.
- Establishment
- The Iowa publication favors drilling over surface broadcasting.
- Soils
- Performs best on well-drained soils.
Water & soil context
- Moisture (VWC)
- The cited publications do not provide numeric volumetric water content sensor targets.
- Salinity tolerance
- The California chart rates salinity tolerance as low, without a numeric threshold.
- Drought tolerance
- The California chart rates drought tolerance as fair.
Illustrative monitoring-depth band
3–8 in
Editorial placement example, not a validated optimum or total rooting depth. Confirm the site's root distribution and soil horizons; multiple depths may be needed.
The Iowa fact sheet warns that excessively drained soils can limit fall performance. Moisture needs cannot be inferred from qualitative drought ratings alone.
Problems to watch
- Can harbor lygus bugs.
- Can serve as an alternative host for Rhizoctonia and Sclerotinia species near susceptible crops.
- Surface broadcasting can give unreliable establishment.
Stress signs
- The cited sources do not provide a reliable phacelia-specific visual stress diagnosis list.
Where you'll find it
- Cover crop
- Pollinator habitat
- Nitrogen catch crop
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Published botanical and soil references are distinct from GroundWorx product guidance. Moisture thresholds and monitoring depths require site calibration; sources do not establish product performance or diagnose stress.