Green Culture Propagation Plugs vs Stone Wool - Starting Seeds

A Controlled Comparison of Seedling Growth & Root Development

This trial compares Green Culture propagation plugs and stone wool cubes under controlled conditions to evaluate differences in growth rate, biomass production & root development

Three crop types were used:

• Tomato
• Basil
• Bok choi

The purpose was to observe measurable differences in plant performance when all variables were held constant except for the propagation medium

Trial Conditions

The following parameters were standardised across both propagation mediums over a 21-day trial period:

• Seed source: Same batch, planted at the same time
• Lighting: Identical indoor conditions
• Nutrient solution: FloraFlex B1/B2 powders
• Electrical conductivity (EC): 0.8
• Watering interval: Every 4 days
• Environment: Consistent across all samples

The only variable was the propagation medium:

• Stone wool cubes (left side in images)
• Green Culture propagation plugs (right side in images)

Image below shows that tomato seedlings grown in Green Culture 'Prop Plugs" grew noticeably larger & produced more biomass.

1. Observed Growth Rate

Across all three plant types, differences in growth rate were recorded.

Plants grown in the Green Culture Prop Plugs showed:

• Greater vertical height at the same time point
• Larger leaf surface area
• More developed structure

Plants grown in stone wool showed:

• Reduced vertical growth
• Smaller canopy size
• Slower development rate

These observations were consistent across tomato, basil, and bok choi.

Image below shows that basil seedlings grown in Green Culture "Prop Plugs" grew noticeably larger & produced more biomass. 

2. Root System Development

Root systems were examined at the same stage of growth.

Propagation plugs showed:

• Dense, white root mass
• Even distribution throughout the medium
• Higher visible root tip activity

Stone wool showed:

• Less uniform root distribution
• Lower apparent root density
• More concentrated root zones

Image below shows that Bok Choi seedlings grown in Green Culture "Prop Plugs" grew noticeably larger & produced more biomass. 

Consistency Across Crop Types

The same patterns were observed in:

• Tomato
• Basil
• Bok choi

This indicates that the differences observed were not specific to a single crop type under the conditions tested.

Summary of Observations

Based on our observations, the improved performance of the Green Culture "Prop Plugs" propagation plugs appears to be linked to their ability to maintain a more stable & consistent root zone. 

The "Prop Plugs" retained moisture more evenly over the 4-day watering interval, reducing visible dry-back compared to stone wool.

The "Prop Plugs" provide a balance of water retention and air-filled porosity which allows for consistent oxygen availability in the root zone. Together, these factors likely contributed to the more consistent growth & root development across the 3 plant types.

Commercial Customers: 

This test is a great example of how you could shave weeks off of your commercial growing cycle by using high quality inputs - time is money, quicker veg times lead to more yearly cycles and improved bottom line!

Green Culture Prop Plugs - FIND HERE

Now go grow some plants!