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Soil Blocking for Seed Starting

mediumGardening60-90 minutes7 steps

Safety Warnings

  • Avoid over-watering to prevent damping off
  • Use clean materials to avoid introducing soil-borne pathogens

Tools Needed

stainless steel hand trowel — sturdy pointed blade for packing soil
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wooden board — flat, smooth surface for compressing blocks
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Materials

leaf mould — decomposed organic matter(1 part)
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sand — coarse horticultural grade(1 part)
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sod/loam — pulverized surface soil(1 part)
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Steps

1
Prepare the soil mixture by combining one part sod, one part leaf mould, and one part sand to create a stocky growth medium.
Tip: Avoid adding manure to starting soil to encourage the hardest, stockiest growth possible.
2
Fill the soil blocking container and press the soil down firmly using a smooth wooden board.
Tip: Pressing the soil promotes capillarity, allowing moisture to be drawn up from below.
3
Sow seeds into the prepared blocks, ensuring they are not covered too deeply.
Tip: Very small seeds need hardly any covering; they often fail to sprout if buried too deep.
4
Firm the soil immediately around the seed using the back of a tool or a board so the seed is pressed close on all sides.
Tip: This ensures the first tiny tap root is in immediate contact with congenial surroundings.
5
Water the blocks thoroughly, ideally toward the evening, ensuring the soil is moist but not packed by the force of the water.
Tip: Avoid sprinkling or dribbling; a thorough soaking is more effective.
6
Maintain a consistent moisture level and keep the surface clear of weeds while the seedlings develop.
Tip: If the soil is very dry, apply water directly to the bottom of the block to avoid surface crusting.
7
Thin the seedlings as soon as they have produced their first true leaves to give them room for proper development.
Tip: Perform thinning on a cloudy day when the soil is moist to reduce plant stress.

Pro Tips

  • For slow-germinating seeds, soaking them in tepid water for 24 hours before sowing can hasten growth.
  • Test the viability of old seeds by planting a small sample in sand before committing to full blocks.

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Sources

Synthesized from 5 verified sources:

Gutenberg: Home Vegetable GardeningView →
Gutenberg: War Gardens GuideView →
Gutenberg: A-B-C of Vegetable GardeningView →
Gutenberg: Manual of GardeningView →
Gutenberg: Farm Gardening GuideView →