"Adequate air circulation is crucial for strong root development"

Using the right substrate is crucial in any form of cultivation. It affects efficiency, root structure, growth rates, and water usage. Dutch growers Rob Varekamp and Ron de Zeeuw of greenhouse company Varekamp de Zeeuw, with over 30 years of experience in the tomato growing business, truly understand how critical that choice is.

They recently made the switch to Jiffy Growbags as the substrate for cultivating their premium Tommies snack tomatoes. "We firmly believe that natural mediums like coir not only promote healthier plants but also deliver superior quality to the consumer," says Rob.

Why the switch to coir?
Varekamp de Zeeuw is committed to corporate responsibility in its tomato growing practices. With sustainable growing as one of their core values, they are constantly looking for innovative solutions to implement this.

Previously, they used stone wool as a substrate. While it was adequate, they preferred a more natural growing medium for their tomatoes. Ten years ago, following their supplier's suggestion, they transitioned to coir substrates, and have never looked back.

'Using coir grow bags creates a circular system that minimizes waste,' explains Ron. 'The process begins with using finely chopped coconut leftovers from the coconut industry. With these, we prepare the coir, which is used for tomato cultivation. Once the plants have grown, we can repurpose the used coir as a growing media for retail.'

Coir also supports a healthier root environment, the Jiffy team says. "Unlike sterile substrates, it allows beneficial fungi and bacteria to coexist around the roots. This fosters a balanced microbial ecosystem, which in turn helps plants build resilience against diseases."

Priorities in picking substrates
In selecting a new substrate partner, Varekamp de Zeeuw prioritized consistency, water efficiency, and oxygen availability. 'We focus on ensuring a good oxygen ratio around the roots of our tomatoes. Adequate air circulation is crucial for strong root development,' says Rob. 'Consistency also plays a key role, and the substrate must ensure that it does not compact or lose its air-holding capacity over time.'

Jiffy Growbags, made entirely from RHP-certified coir, met those demands. Their high-performing structure offers excellent water retention, air capacity, and rewetting properties. In fact, under saturated conditions, the air content in Jiffy Growbags can reach up to 44%, promoting healthier roots and faster establishment. This translates into 15–20% quicker root development compared to mineral-based alternatives.

Jiffy's natural buffering properties also stabilize pH and EC levels, reducing fluctuations and making nutrient management more precise. 'We prioritize quality over quantity – even if yields are slightly lower, we're confident we're bringing a better product to market,' Rob adds.

Transitioning to Jiffy
The switch to Jiffy Growbags was straightforward. Having already worked with coir growbags, Varekamp de Zeeuw didn't need to overhaul their systems. Jiffy's team offered support throughout the process, and the new growbags integrated seamlessly into existing operations.

The growbags' slightly coarser texture offered unexpected advantages. 'In our experience, other options can sometimes resist moisture absorption at first, making it more challenging to achieve the right swelling and moisture distribution,' Rob explains. 'With Jiffy Growbags, however, we noticed that the initial wetting requires less water, and the slabs absorb it quickly and efficiently.'

Results and savings
The team closely monitored the tomatoes' moisture and nutrient needs, adjusting the irrigation as required. To ensure top-quality harvests, the plants must be encouraged to actively take up both water and nutrients, which demands accurate timing and precise, targeted irrigation strategies throughout the growing season.

Thanks to the growbags' high capillarity and fast rewetting, many growers – Varekamp de Zeeuw included – report using 10–15% less water during the saturation phase. This helps make irrigation more efficient and provides greater control over nutrient delivery, especially during peak demand or fluctuating weather.

For Varekamp de Zeeuw, the move to Jiffy Growbags was a natural next step in their ongoing pursuit of quality, efficiency, and reliability. With over three decades of experience in tomato cultivation, their decision was grounded in data, observation, and a clear understanding of what their crops need to thrive.