Evolution of the Mobile Seed Cleaner

Posted on Monday, 17 September 2018 under Mobile Seed Cleaning Trailer

Over the past few months we have been designing and sourcing materials for our mobile seed cleaner – a collection of mid-scale seed cleaning equipment for use by local seed growers and farmers. The design is based on an existing trailer at the Organic Farm School in Washington State. The goal of the trailer us to help seed growers scale up production to better provide bulk seeds to farmers.

There are two major infrastructure components of the project: the trailer itself and a Clipper AGM 224 fanning mill. Sourcing and purchasing both has helped me understand them both much better!


The trailer is going to house the seed equipment and make it mobile so it needs to be well chosen. Some of the considerations when buying a trailer are:

Customization: Most trailer suppliers will customize a trailer in 4-10 weeks

Size and Dimensions: It must be large enough to fit in all the equipment, especially the Clipper. After much fretting, the width needs to be at least 7 feet. Length can be as short as 10′, but currently we are looking at a 12′ length to make more space for storage and workspace inside. Most trailers are quite short so we need to get added height to make it comfortable to work in.

Axle: Trailer typically come with simple “spring” axles, but more “advanced trailers have “torsion” axles which gives them a smoother ride – very important for a trailer that is being pulled around a lot. The torsion ales are much more expensive. For our use, the spring axle will work fine as the trailer will not spend that much time in transport. Trailers also come in single and double axles. Double axles are needed for trailers pulling heavier loads and add much more cost. We will use a single axle trailer

Side doors: To orient the Clipper sideways in the trailer there must be a side door on both sides of the trailer to allow space to load screen one end and harvest seed on the other. Adding adoor to a custom trailer is only about $150 for the model we are looking at. Wide doors are better so we are looking at 36″ width for easier access

Deck height: A lower deck can make loading heavy stuff onto the trailer much easier. It is also an additional cost

Vents: Side and roof vents encourage air flow and reduce the likelihood of mold
Trailer weight and electric brakes: Trailers over 3000 lbs (with load or without) are required to be equipped with electric brakes. This requires the appropriate connection on the tow vehicle and adds significant cost. The base weight for our trailer thus far is 1000 lbs with an additional 800 lbs for the Clipper. MOst other equipment will be much lighter so we can stay with a non-electric brake model.

Stabilizers: The trailer needs support stabilizers in the back when parked to avoid tipping. We will have these built right into the trailer frame to make them easier to engage – this is important as ther trailer will be used by many different people and needs to be safe. It is unlikely this trailer will tip as the Clipper will be positioned on the hitch side.

Lead time: custom fabrication take about 4-6 weeks
So after looking at multiple trailers and designs we will go with a 12 x 7′ trailer with a low deck and doors on both sides. Our price, with tax, is $5400.



The Clipper is a well-known seed cleaner built in the United States. I looked at both US and Canadian suppliers and ultimately chose a US supplier as shipping was much more affordable than the Canadian suppliers. As we are importing this equipment we do have do consider import requirements which the transport company will help with. It does not appear the Clipper is subject to import duties, however the screens are subject to a 6.5% import fee.

It will take 4-6 week to import the Clipper once the order is made.

Once it arrives we need to have place of delivery and unloading. Discovery Organics has agreed to accept delivery for us as they have a loading dock and equipment for moving a large pallet. Once it is unloaded we need to get it onto the trailer using a forklift. Once on the trailer it will be bolted to the trailer base. I will leave a space on the wall side of the trailer to store the 15 screens it will come with.



We are now working with a group of UBC engineering students to design an air column separator based on existing designs but which improves upon their mobility and operation. This is exciting! We are meeting this week to look at seed cleaners at UBC Farm.


Other Equipment

The trailer will also contain:

  • 2 Air Compressors
  • Set of hand screen
  • 2 Box fans for winnowing
  • Rubbermaid totes
  • Various tarps
  • Screen recommendation list
  • Air column separator
  • Seed counting machine
  • Clipper screen frame – to use screens independent of the Clipper for smaller lots
  • 10 x 15 tent (to create outside working space in rainy or intense sun
  • Vacuum for cleaning and
  • May also include:
    – Hand winnower
    – Hand/pedal thresher
    – Zig zag seed cleaner
    – We can also add more equipment in the future.


Safety Supplies

We will have a range of safety supplies in the trailer including:

  • Earplugs
  • Goggles
  • Respirators
  • First Aid Kit