Soak seeds of non-woody plants before sowing: freshwater wetlands

How is the evidence assessed?
  • Effectiveness
  • Certainty
  • Harms

Study locations

Key messages

  • One study evaluated the effects – on emergent, non-woody plants typical of freshwater wetlands – of soaking their seeds before sowing. The study was in a greenhouse in the USA.








  • Germination/emergence (1 study): One replicated, randomized, controlled study in a greenhouse in the USA found that soaking bulrush seeds in water before sowing typically had no significant effect on their germination rate – especially amongst seeds that had not been manipulated in any other way before soaking.

About key messages

Key messages provide a descriptive index to studies we have found that test this intervention.

Studies are not directly comparable or of equal value. When making decisions based on this evidence, you should consider factors such as study size, study design, reported metrics and relevance of the study to your situation, rather than simply counting the number of studies that support a particular interpretation.

Supporting evidence from individual studies

  1. A replicated, randomized, controlled study in 2015 in a greenhouse in Utah, USA (Marty & Kettenring 2017) found that soaking seeds of three bulrush species in water typically had no significant effect on their germination rate. Seeds that had been soaked before sowing had statistically similar germination rate in 24 of 30 comparisons (for which soaked: 6–88%; unsoaked: 1–75%). In the other six comparisons, soaked seeds had a higher germination rate (18–69%) than unsoaked seeds (4–50%). Five of these comparisons involved seeds whose dormancy had previously been broken through chilling and/or chemical treatments. Methods: Field-collected seeds of three bulrush species were sown onto sand in the greenhouse (36–72 sets of seeds/species; ≥100 seeds/set). Seeds in 18–36 random sets/species were soaked for two weeks before planting (in deionized water, changed every three days, 28–35°C). The other sets were kept dry. Some sets were also chilled and/or soaked in chemicals before soaking in water. After sowing, seeds were kept saturated. Germination rates for each set were recorded five weeks after sowing.

    Study and other actions tested
Please cite as:

Taylor N.G., Grillas P., Smith R.K. & Sutherland W.J. (2021) Marsh and Swamp Conservation: Global Evidence for the Effects of Interventions to Conserve Marsh and Swamp Vegetation. Conservation Evidence Series Synopses. University of Cambridge, Cambridge, UK.

Where has this evidence come from?

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Marsh and Swamp Conservation

This Action forms part of the Action Synopsis:

Marsh and Swamp Conservation
Marsh and Swamp Conservation

Marsh and Swamp Conservation - Published 2021

Marsh and Swamp Synopsis

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