Seed Sowing Standard Operating Procedure

Seed Sowing Standard Operating Procedure#

Composition: In-house made Seed Sowing Medium (SSM) - see recipe book for details.
- Ingredients: Peat, Soil, Turface.
- Note: The only nursery planting media that incorporates a fungicide (Truban).
Storage: Store dry to avoid pathogen build-up.
Preparation:
- Moisten the medium before use.
- For small batches, avoid oversaturating as it won’t pass through the screen.
- Ensure the medium is moist enough to not be hydrophobic when watering.

Fill a ‘blank’ pot with SSM to the top of the pot.
Shake excess so that the seed sowing medium is level with the top of the blank.
Fill the seed pot with SSM from the blank.
Gently shake the seed pot to even out the material.
Tamp the surface of the pre-seed bed using the weight of the metal tamper.
Using a screen, apply a light layer of SSM fines to the top of the pot.
Clean up the edge of the 4” pot by lightly tapping on the side of the pot (use tweezers or dibber).
Tamp the surface again under the weight of the metal tamper.

Label Check: Ensure the label information matches the packet/card information.
- Name, accession #, component, sow date, and number of plants requested.
Seed Quantity and Quality:
- Identify a single seed and rapidly estimate the number of seeds available in the lot (if not indicated on the packet).
- For commercial seed, check the packaging date and germination percentage.
- For small seeded wild-collected material, inspect a sample under a microscope.

Consider the source (Wild Collected vs. Commercial) and the number of plants requested.
Assume a wild-collected germination percentage (Germ%) of ≤ 50%.
Maximum Number of Seeds Sown per Pot (depends on seed size):
- Very large (e.g., Quercus): None, use other methods (e.g., direct ziplock).
- Large (e.g., Tilia): 25 seeds.
- Medium (e.g., Picea): 50 seeds.
- Small (e.g., Betula): 75 seeds.
- Very small (e.g., Rhododendron): 100 seeds.
Requests requiring more seeds than the seed pot maximum should be split into multiple seed pots. Extra labels should be written, and a GREEN dot affixed to the labels to indicate this.

Check Sowing Depth Instructions (e.g., surface sown, light cover, or none).
Distribute the seed across the surface of the seed bed.
- Empty the seed packet onto a piece of paper.
- Gently shake the paper at a 30-degree angle to distribute the seed.
- Larger seeds can be placed with tweezers.
- Very small seeds can be mixed with silica to help with even distribution.
Cross-Hatch Sowing:
- Sow ½ the seeds for the pot, turn the pot ¼ turn, and sow the rest.
Set Seeds:
- Use the tamper to set the seeds into the seed bed (using the weight of the tamper only).
- Brush off the base of the tamper to dislodge any stuck seeds.

Pass the screen with SSM fines over the top of the pot.
Ensure approximately 10% of the seeds remain partially visible.
Apply a light granite grit cover so that the SSM cover is still visible between the stones.

Completely cover the seeds.
Ensure no seeds are visible.
Apply a granite grit cover so that no SSM cover is visible (but not too thick).
Ensure the top of the finished cover (SSM fines and granite) sits just at the inner edge of the seed pot (3/8” from the top of the pot).