Lahtelan Puutarha, a family-run greenhouse business in Finland, has relied on Grodan’s stone wool solution for more than 20 years. With this trusted partnership, they now produce clean, high-quality lettuce year-round — all while working more sustainably and efficiently.
When Juha, owner of Lahtelan, first considered changing his lettuce-growing substrate, it wasn’t because he wanted to follow trends or make radical shifts. It started in a familiar place — the old greenhouse at his parents’ home — where he noticed Grodan plugs being used for Chrysanthemum seedlings.
Back then, Juha’s lettuce cultivation relied on the traditional combination of plastic pots and peat. It was a routine he knew well, but it came with challenges: space requirements, time-consuming residue checks, and a lot of manual effort to separate peat from roots at harvest.
Switching to Grodan stone wool plugs seemed like a leap at first glance. But once Juha experienced the ease of harvest — simply cutting the plug from the lettuce crop without any residue checking — he saw the true value. The cost balanced out in the end, and the workload dropped significantly. As Juha puts it, “No more peat stuck to lettuce leaves — it was cleaner, simpler, and better all around.”
Discovering New Advantages
Juha’s transition to Grodan stone wool wasn’t without surprises. The real game-changer came with the flexibility of the sowing process. With Grodan plugs, Juha could sow directly into dry stone wool, store the prepared sowings in cooler conditions, and pause germination until needed. Germination was then started once the plugs were saturated with a nutrient solution at the correct EC. This meant no more daily sowing schedules or working weekends — while still maintaining an even, consistent crop rotation.
“This was transformational for our workflow,” Juha recalls. “It gave us freedom without sacrificing quality.”
