Improved Method for Maintaining Soil Moisture Levels for Plant Seedling Research

Semipermeable membrane systems are available, yet, plant seedling research requires adaptations that allow for consistent performance by utilizing materials that encourage adequate growth responses. Soil‐filled semipermeable membrane envelopes, enclosed in 1‐cm‐thick stainless steel wire frames, equilibrate with polyethylene glycol (PEG) 10000 solution with osmotic potential (ψ π ) of −0.4 MPa within 36 h and equilibrate with −0.8 MPa solution within 60 h. Linear relationships existed between predawn plant water potential (ψ), soil matric potential (ψm), and PEG ψ π . Improvements compared with previously reported methods included reduced equilibration time and stainless steel frame construction which aided in avoiding Zn toxicity associated with galvanized metal.