How to Make Your Compost Better (Yes, Biochar Gets a Shout)

Episode Overview

• This episode of Growers Daily is a comprehensive compilation of segments dedicated entirely to soil blocking, a sustainable seed-starting method preferred by many ecological farmers.
• The episode covers the practical mechanics of using different types of soil blockers, compares soil blocks against alternative seeding trays, and answers common grower questions about managing root health and watering.
• It addresses the frequent challenge of managing mold, algae, and fungal growth on fresh soil blocks, providing actionable advice for greenhouse management.
• This guide is essential for market gardeners and home growers looking to improve seedling vigor, eliminate plastic waste, and optimize their propagation systems.

Key Concepts

• The Importance of Moisture Consistency: The most common mistake in soil blocking is incorrect moisture. The soil mix must be wet enough to hold together—possessing a consistency similar to oatmeal with small puddles at the bottom of the mixing tub—but not so wet that the blocks melt or lose structural integrity upon release.
• Air Pruning vs. Root Bound Trays: Unlike standard plastic cell trays where roots circle endlessly and become root-bound, soil blocks allow for "air pruning." When plant roots reach the edge of a soil block, the open air stops their growth, signaling the plant to branch out internally. This creates a highly robust root system that suffers zero transplant shock.
• Microbial Dynamics on Block Surfaces: The appearance of fuzzy white molds, mushrooms, or green algae on soil blocks is highly common due to the moist, nutrient-rich greenhouse environment. While mostly harmless, thick algae can create a hydrophobic (water-repelling) layer on top of the block, preventing water from penetrating to the roots.
• Hardening Off Advantages: Seedlings grown in soil blocks typically require less "hardening off" (gradual exposure to outdoor conditions) compared to tray-grown seedlings. Because their roots are already exposed to air and highly developed, they adapt to open soil much faster.

Quotes

• At 2:08 - "In my opinion, without question, the number one thing people mess up about soil blocking is the moisture level. They get it too dry... you want it kind of the consistency of oatmeal... where you can squeeze a lot of moisture out." - Explaining the critical starting state required for block stability.
• At 8:31 - "For soil blocks, you have to start with a decent soil mix... it’s essential so that the mix actually holds together... Often when people are having a bad time with soil blocking, they are just not using enough water in the mix to start." - Stressing that physical mix properties and water ratios dictate success.
• At 20:11 - "Algae can create hydrophobic layers on top of the soil block that will repel above watering, which means the soil block does not get saturated enough... that's where bottom watering will come in handy." - Clarifying how surface microbial growth physically blocks water absorption and how to bypass it.

Takeaways

• Optimize Seeding Speed with the Right Tool: Match your blocker to your farm scale. Use hand blockers (like the 4-blocker) for small batches, standing multi-blockers (like the 35-blocker) to save your back, or a "Swift Blocker" to quickly press up to 200 micro-blocks directly into a standard 10x20 tray.
• Lubricate Your Blockers Regularly: Always dip your soil blocking tool into a bucket of clean water between every press. This provides lubrication, prevents the muddy soil mix from sticking to the metal chambers, and ensures clean, clean-cut blocks that release easily.
• Combat Greenhouse Mold with Strategic Airflow: If fuzzy mold or damping-off fungi appear on your blocks, position a circulation fan to blow air just above the trays rather than directly onto them. This keeps the air moving and dries standing water droplets on the stems without prematurely drying out the root blocks.