Miljøgartneriet in Naerbø in Norway is a modern horticultural enterprise that grows various varieties of tomato, sweet pepper and chilli pepper. Miljøgartneriet also propagates plants. The company takes a pioneering role when it comes to environmentally-friending growing methods. Grodan Pro blocks contribute to their aims, as the plants develop with even greater uniformity and the blocks enable more accurate irrigation and fertilising. The loose tomatoes have been grown on 10 cm high slabs since this year, resulting in 10% higher production.

Miljøgartneriet is a relatively young company and covers around 7.5 hectares. Owners Kåre Wiig and Hallstein Aase built the company in 2009 / 2010 next to the TINE Meieriet Jæren dairy plant. The dairy plant runs on natural gas and 'green' electricity generated by hydropower plants. The nursery utilises the residual heat and CO2 produced by the dairy plant.

“Our greenhouse is the most environmentally friendly in all of Norway. Not only thanks to our symbiotic relationship with the neighbouring dairy plant, but also because we do not use any form of chemical crop protection, re-use our waste water and do not waste any fertilisers or nutrients”, proudly explains Simon Hansen, the Danish crop manager. After 17 years of tomato growing in his home country, Simon started working at Miljøgartneriet in 2011. Miljøgartneriet also propagates seedlings for its own use, and for colleague growers - tomatoes, sweet peppers and cucumber plants.

Uniform plants
Hansen can follow the entire development of the crops from seedling to fully grown plant. He chose Grodan Pro blocks for all three crops. The tomatoes are planted in 10 x 15 cm blocks, the sweet peppers in 10 x 10 cm blocks and the dimensions used for cucumbers depend on the customer's specifications.

Before transitioning from Plantop to Pro blocks, Hansen ran a series of trials to compare the systems. “Pro blocks have a better water retention capacity and are more homogeneous. We don't have to irrigate before spacing the blocks out. Our plants are propagated on tables, and the blocks around the edges are not drier than the ones in the middle. This means fewer plants are lost. The Pro blocks are more expensive than Plantop blocks, but as we can now start propagation with 3% extra seedlings instead of 4% our costs are actually reduced. How much we save depends on the variety. The savings are higher with more expensive seeds.”

A second benefit is better root development. “The roots spread out all through the block instead of concentrating at the base. They then grow quickly and evenly into the slab. The result is plants with excellent uniformity, which enables optimal plant management. And there are fewer problems with pythium.”

Easier to handle
The firmer structure of the blocks offers extra benefits to growers. This structure makes it easier to handle the block in automated systems. When being lifted or spaced apart, the optimal water and air balance in the blocks is left intact. And the stakes are also held more tightly in place in the firmer Pro blocks. “Inserting the stakes again takes time. And time is money. Some of our customers want larger tomato plants with a second vine showing. The firmer blocks are the ideal solution for these plants that need stronger stakes.”

Higher slabs
For the larger, loose tomatoes, the manager opted for higher Master slabs: 10 cm instead of the standard 7.5 cm. He still uses the standard height for smaller tomatoes. Master Dry slabs of 7.5 cm high are currently used for sweet peppers, but he is considering using higher slabs.

The choice for higher slabs was driven by the wish to grow more plants per slab. “We used to start with 2.5 plants/m2. By keeping an extra stem, we increased the plant density to 3.3 plants/m2. With the larger tomatoes, we now have switched to growing 3.7 plants/m2 right from the start. That converts to six plants per slab, which requires a greater substrate volume. This is our first year, and the results so far are good. The crop is more uniform with greater consistency in fruit size, so the harvest is also more homogeneous. Compared with last year, the yield up to September is about 10% higher.”

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