Dealing with hard-to clean seeds
“Put well-dried bean pods in a bag and stomp on it with both feet.”
Seed saving is easy, interesting and rewarding, I always tell people each spring. A lot of them believe me until it comes time to clean their seeds. How many hours have I spent picking seeds out of pods, chaff and flower fluff? More than anyone should enjoy, but there are shortcuts that I wish I’d known years ago. So many books tell us how to prevent cross-pollination, how to store seeds, when to harvest, but they tend to leave out the best tips about seed cleaning, which is why so many people are doing it the hard way.
Why clean seeds?
First of all, do you really need to clean your home-saved seeds to seed-packet perfection? Usually, no. You clean seeds for two reasons: to remove wet, clinging bits of the fruit, and to make them look nice. If your seeds are dry from the plant (e.g. flower seeds, lettuce seeds), you don’t really have to clean them. Just plant them with the chaff, and they’ll grow. The chaff just becomes compost. Actually, there is a third reason; if the plant matter was diseased or mouldy, you should clean the seeds to help prevent the problem from happening again. On the other hand, it’s not a great idea to collect seeds from diseased plants in the first place.
Sometimes you want your seeds to look nice. Say you’re selling them, or giving them out at your local seed fair. People expect them to look clean. That’s easy for some plants, and difficult for others. The best tool for the job—kitchen sieves and strainers. I have eight different sizes for different kinds of seeds. I’m the kind of person you’ll see at the dollar store peering at sieves like a jeweller examining diamonds, looking for one with just the right-sized mesh. Other low-tech tools include a good, strong fan, some plastic bins that are wide but not tall (with no holes in the bottom), and a good water bucket. A few old feed bags are useful too.
Small, dry seeds with no fluff
By far, most seeds are harvested dry from the plant. They only need to be separated from their pods or capsules, and any leaves or stems that get into the mix. Flowers are especially common in this category: snapdragons, nicotiana, poppy, nigella, and so on. Normally, I clean these with two kitchen sieves. I choose one with a mesh just a bit smaller than the seeds, and another just a little bigger. With the bigger mesh first, stems and capsules get caught but the seeds go through. Then the seeds get caught in the next mesh but the dust goes through. Very simple and fast.
Small, dry seeds that get lost in their fluff
Many herbs and flowers have a fluffy seed head that tends to trap the seeds. Lettuce is particularly annoying for this. Honestly, half the time I don’t bother to clean lettuce seed. But if you must, it can be done with a little effort. Put the seed heads in a dry bucket or a large bowl. Crush the seed heads with your fingers until there are no lumps. Then bring an electric fan outside. Even in cold weather, it’s better than getting the fluff all over your house. This is the tricky part. By sprinkling handfuls of fluff in front of the fan, you can catch the heavier seeds in a wide bin as they fall, but blow the fluff and dust away. Believe it or not, this is the level of technology that many seed companies use to clean these kinds of seeds. It takes some practice to drop the seeds just the right distance from the fan, and at just the right height, but you’ll be rewarded by fairly clean seeds in the bin. It might take a few repetitions to get the seeds really clean. You’ll probably also get heavy pieces of stem in the bin, but those can be removed with a kitchen strainer.
Seeds in pods
What about bigger seeds that come in pods? Beans, peas, cabbage and kale (if you’re really serious). I used to shell the seeds by hand, pod by pod. What a waste of time! Now I know better. The seeds are tougher than you’d think, so you can shatter the pods in many fun and stress-relieving ways. Here’s where the feed bags come in handy. I put well-dried bean pods in a bag and— literally—stomp on it with both feet. Then the electric fan method blows the shattered pods away from the seeds. Nice and clean, and in a fraction of the time I used to take. Just be sure to turn the bag inside out and remove any hidden seeds before you use it for another variety.
Wet seeds in blobs of jelly
Tomato and cucumber seeds are frequently saved, but they are unusual in the seed world in that every seed comes in a little blob of slippery jelly. This is one aspect of seed cleaning that has been well discussed in seed saving books, but it often sounds intimidatingly difficult. For small quantities, say for your own use, all you have to do is rub the jelly off with a cloth. Then let the seeds dry. For larger quantities, it’s too difficult to rub every seed, so the standard method is to rot the jelly away. Put the seed pulp in a container with a lid, and let it sit for three days at room temperature. If you don’t have time or inclination to cut and scoop each fruit, you can just crush them whole with a 2×4 in a big bucket. After three days, the seeds should be free from the jelly, and they should have sunk to the bottom of the container. Simply pour off the smelly liquid, fill with fresh water, and pour it off again. It might take another rinse, but you’ll have nice clean seeds at the bottom. Note that the seeds might start to sprout if you leave them for longer than four days, so don’t forget about them. You can’t put the little roots back in once they sprout out!
Wet seeds attached by strings
Have you ever tried to clean pumpkin seeds at Hallowe’en? Usually, I do that to roast and eat the seeds, but my purposes are just as valid as any. Each pumpkin seed is attached to the inside of the fruit by a string: essentially an umbilical cord. When you pull a handful of seeds out of a pumpkin, or any kind of squash, the seeds stick to your hands. The strings stick to the seeds. Pumpkin bits stick to everything. It’s all good to eat, but it doesn’t look beautiful. The trick is to go underwater. Drop the handfuls of pumpkin pulp into a bucket of water. Agitate the pulp with your fingers, and the seeds will separate easily and cleanly.
Wet seeds in firm fruit
Not many people try to save seeds from eggplant, but when they do, they always ask “How in the world am I supposed to do this?”. Eggplants are very tough when raw, and the seeds are scattered throughout the firm flesh. They soften when cooked, of course, but that kills the seeds. If you’ve never attempted it, try to pick the seeds out of a raw eggplant. It’s remarkably difficult. Again, water is your friend. Cut eggplants into two-inch chunks. You’ll cut some seeds, but that’s unavoidable. Then soak the pieces in a bucket of water for a minute, and press the seeds out with your fingers underwater. It still takes a bit of effort, but it’s surprisingly easier than doing it dry. The water temperature doesn’t matter to the seeds, but warm water is comfortable on the hands. Other fruit that suit this technique are citron melon, tomatillos, and ground cherries.
Finally, the fruit that lets everyone be a seed saver. Obviously this isn’t a difficult seed to save, but it’s fun to comment on it. I’m always happy to share watermelon from the garden, but at my house there’s a rule—spit your seeds in a bowl and give them back to me! I always thought that was half the fun. I don’t mind seedless watermelon, but I think my kids should eat real watermelon with seeds, just so they can learn what watermelon-eating is really all about.