28 Sep 2021

Apprentice Blog: Harvesting Wildflower Seed with Rowan Moses

Rowan Moses

Harvesting wildflower seeds from natural meadows was a kind of project that I’d never been involved in before, and it was very exciting to see the whole process from start to finish.

There were lots of factors to consider. First, it depended heavily on the weather. The harvester used nylon brushes to sweep over the field and collect the seeds out of the dried seed heads, and if it was raining, the seeds would just stick to the plants! However, we also couldn’t wait too long in the year, or we would miss the cream of the crop because the ripest seeds would already have fallen. We were watching for the perfect opportunities throughout the harvesting process, and jumping on them!

Once we had a dry day, we were ready to begin harvesting. The seed harvester was pulled along behind our vehicle, collecting seeds, still mixed with grass and chaff, into the hopper. When we’d collected the seeds, we would spread out everything we’d collected, and leave it to dry. We had moisture meters, which would tell us the percentage of moisture in the chaff.

This was my favourite part, seeing the moisture content fall day by day as we kept checking on it was very cool.

On one occasion, the moisture content suddenly started going up! We traced that back to the wind blowing the rain in, and moved the drying material, but it was a confusing moment.

The part of the process that was the most time-consuming was definitely the sieving.

Once the grass and seed mix we’d harvested was properly dry, we hand sieved it all, going through the especially rough bits twice to extract all the seed and throw out the chaff. By the time we’d worked our way through it all, we had speed sieving down to an absolute fine art. The sacks we filled with seeds were then taken up to the Science Centre to be weighed and then stored where they’d be dry.

We had seeds for a variety of different wildflowers, but the one we had most of was definitely yellow rattle, Rhinanthus minor. Yellow rattle, which gets the name from the way the seeds rattle if you shake a dry seed head, is semi-parasitic. This means that as well as photosynthesizing like normal, it takes nutrients from the neighbouring roots of grass, which is vigorous and fast-growing. This siphoning of nutrients keeps the grass down, allowing slower-growing meadow species to flourish and not be instantly out-competed. The seeds are flat and brown, and every day I found them in my boots after I’d finished sieving, so it’s ingrained in my memory what they look like.

It felt really satisfying to be involved in local meadow restoration in such a hands-on way, and I learnt so much from everyone else throughout the project. Thanks everyone!