As a new seed saver I used to work delicately with seed crops to avoid any damage and minimize seed loss. This worked well for plants like arugula that have seed that shatters easily and light chaff. But radishes, with their big spongy pods that squished before shattering and left pieces of pod the same size as the seed, gave me a headache. And after a couple miserable attempts, I gave up on radishes for many years.
Four years ago, with some seed saving experience, I tried radishes again with success. The differences in my approach came down to making sure the pods were very dry and not being too delicate with the extraction process (quite the opposite in fact!).
I clean radish seeds with multiple cycles of threshing, screening and winnow steps in my radish cleaning. This is what I call aggressive seed cleaning and use this approach with seeds that don’t easily shatter (snap beans, and now chicory, fall in this list).
This post covers the radish seed cleaning, you can read about growing the plants for seed here:
On with the cleaning!
We harvest the plants when they’ve dried down in the field. Then let them dry further in the barn
When they are dry, I put the plants in a bin and stomp them with my boots.
I screen out the plant stems and largest material with a 1/2″ screen.
This is what fell through the screen. There are still a lot of whole pods in here.
I run this through a 1/4″ screen. The whole pods stay on top.
This is the chaff and seed (with a few whole pods) that went through the second screen. I leave this in a bin and pay attention to the pods that didn’t fall through.
This is what didn’t go through the screen.
I stomp on the pods some more and then screen again the 1/4″ screen. I add what falls through the screen to the bin with what fell through during the previous step. I repeat with any pods that didn’t fall through the mesh.
After a few passes all the plant material has fallen through the 1/4″ screen and is collected in one bin.
I take this bin into the barn.
I transfer the chaff and seed to a bucket and then winnow.
I start with the fans on low-speed and crank the speed each successive pass till I achieve desired results. In the case of radish seed both fans are at high-speed.
I winnow over three bins on a tarp. I can recuperate my seeds if I have a fanning mishap, and also I can see what is being separated at different steps.
The left bin (closest to the fan) is full of seed and non-shattered pods. The bin on the right is full of stems and shattered pods.
Repeat Threshing And Winnowing
I compost the plant matter from the bin on the right and screen the bin on the left with my 1/4″ screen. crushing anything that doesn’t go through with my boots.
After another cycle or two of screening and winnowing, the large plant matter has been removed from the seed.
Only the seeds remain with a few big bits. At this point I take out my specialized radish screen.
This is one of my fine collection of colanders, the square holes are the right size for radish seed.
I pour the seed into the colander and delicately shake from side to side …
separating the last bits from the seed lot.
I lay the clean seeds on a tray to dry a few more days than bag them up to bring them into the office.
As you can see I really kick the seeds out of those pods – hence aggressive seed cleaning. Getting the seeds free from the pods is the critical first step in seed cleaning. From that point on screens and fans can do the rest.
Next, I’ll talk about how aggressive winnowing does the job for lettuce seed.