How We Handle Late Weeds in Organic Flax

Our winter flax harvest is already underway. But before the first combine went into the field, we had one important job left: topping the weeds.

Unlike other grains, flax isn’t great at outcompeting weeds. That’s why we keep a close eye on late-stage weed pressure. This year, weed growth meant we had to step in, and the Zürn Top Cut Collect machine was the right tool for the job.

Watch the full video to see why and how we use it.

We don’t always perform weed control on flax. But in some fields, high weed pressure from chamomile, mustard, volunteer oats, and even some wild rye made it necessary.

Here’s why:

• It reduces green biomass going into the combine,
• improves grain cleanliness,
• helps manage the weed seed bank, and

protects the value of a high-priced crop like organic, gluten-free flax.

We harvest flax when it’s dry and mature, but if moisture-loving weeds like chamomile are still green, they can cause problems during harvest.

How we use the Top Cut Collect

The Top Cut Collect is a 12-meter-wide, towed implement designed to top weeds above the crop canopy. Here’s how we set it up:

• Cutting height: Just above the flax canopy, to avoid crop damage.
• Reel and cutting bar: Adjustable for weed density and field conditions.
• Conveyor belt: Moves topped weeds into a holding bunker.

Each segment can be independently controlled, giving us better results on uneven terrain. But that terrain also presents one of the main challenges: maintaining consistent height to avoid accidentally cutting the crop.

If weed pressure is too high, the holding bunker fills up quickly — meaning more frequent stops to unload.

What happens to the weeds?

Nothing goes to waste. After topping, we collect the weeds and store them in compost piles. Once decomposed, they’ll return to the field as nutrient-rich organic fertilizer.

Not every field needs it

We didn’t top weeds in all the flax fields. Some had low pressure or only a few scattered weeds that posed no risk at harvest. The decision is always made based on:

• Crop condition,
• weed species present,
• expected harvest date, and
• moisture content.

In one field, volunteer oats were the issue due to leftover seeds from a previous crop. In another, it was a mix of several weed species that made topping necessary.

Organic farming is about observation and adaptation. That’s what this operation was all about.