Improving germination by saturating trays before sowing

A high germination rate is essential for every plant grower, but optimizing it remains a challenge. Have you already implemented most improvements? Thom van Wesel, application specialist at Cultilene, shares a practical tip that can make a difference: saturate your trays the day before sowing to improve germination.

Saturating earlier: increase oxygen levels
Most plant growers saturate trays whilst sowing. This is the most efficient way to work. However, it can be worthwhile to saturate the trays a day earlier.

Why? Immediately after saturation, plugs contain around 95 - 100% water. This means there's almost no oxygen available to the seeds. Oxygen however is necessary to start the germination process.

By saturating the trays and than waiting a day, the water content in the plugs lowers to 75 - 80%. This creates more air exchange in the pores, allowing oxygen to reach the seeds more easily. With more oxygen available, seeds have a better chance of germinating successfully.

© Saint-Gobain Cultilene

Benefits of saturating earlier
Saturating trays earlier does require extra effort. You need to prepare trays a day in advance, possibly running them through your production line twice, which can be more labour-intensive. The question is: is the extra work worth it?

Experience shows that this method can increase germination rates by an average of 0.5%. While this may seem small, the impact can be significant when you consider the cost per seed and the total number of seeds you process.

In addition, a higher oxygen level during germination contributes to healthier seedlings overall. Seeds that germinate in oxygen-rich conditions tend to develop stronger and more uniform root systems, which improves water and nutrient uptake in later stages. This leads to more uniform plant development, better crop predictability, and fewer weak or underperforming plants in the tray.

And there is another advantage: saturating trays earlier can also shorten the germination time. On average, seeds germinate a day faster with this method. Over time, these time savings can allow for more efficient occupation of the greenhouse, enabling you to produce plants faster.

How significant is the improvement?
These improvements can add up to significant advantages during the rest of the cultivation cycle. Lets break it down; a single tray with seeds (usually 252 seeds/plugs per tray) costing around € 0,80 per seed, represents a significant share of total costs at a propagator. Improving germination by only 1% will already generate € 2,- cost saving per tray.