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

Overall effectiveness category Unknown effectiveness (limited evidence)
Number of studies: 1
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How is the evidence assessed?

Effectiveness

30%
Certainty

30%
Harms

0%

Calculating overall effectiveness category

Background information and definitions

Soaking seeds in water before sowing could increase germination speed and percentages, although the effect may vary between species (Marty & Kettenring 2017). This action involves soaking in water at near-ambient temperatures; other actions consider soaking in chilled or heated water.

To be summarized as evidence for this action, studies must have explicitly compared the performance of treated and untreated seeds. Studies that simply report the performance of treated seeds are not summarized here. Studies do not have to be in flooded/saturated soils, as long as they involve wetland-characteristic species.

^{Marty J.E. & Kettenring K.M. (2017) Seed dormancy break and germination for restoration of three globally important wetland bulrushes. Ecological Restoration, 35, 138–147.}

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.

VEGETATION COMMUNITY

VEGETATION ABUNDANCE

VEGETATION STRUCTURE

OTHER

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

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
Referenced paper
Marty J.E. & Kettenring K.M. (2017) Seed dormancy break and germination for restoration of three globally important wetland bulrushes. Ecological Restoration, 35, 138-147.

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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This Action forms part of the Action Synopsis:

Marsh and Swamp Conservation

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Install physical supports for planted trees/shrubs: freshwater wetlands Action Link	No evidence found (no assessment)	Synopsis Link
Install physical supports for planted non-woody plants: brackish/saline wetlands Action Link	No evidence found (no assessment)	Synopsis Link
Install physical supports for planted trees/shrubs: brackish/saline wetlands Action Link	No evidence found (no assessment)	Synopsis Link