Seed Stratification
Stratification/Scarification:
Stratification and scarification: a lot of gardeners have heard these words, but many don’t really understand what they mean or why they matter. I sure didn’t at first. I learned the hard way—by trial and error and a few failures.
One year, I decided I was going to save all the seeds from the muscadine grapes I ate and grow myself a whole new batch of vines. I treated them just like the seeds I save from peppers, tomatoes, and squash: cleaned them, dried them for a week or so, and planted them. Sounded like a solid plan…but not a single seed sprouted. Not one.
I figured I’d either made a mistake or ended up with defective seeds. I shrugged it off and moved on. Then, months later, I noticed something interesting: little grape seedlings popping up all around the original vine. These were seeds that had simply fallen to the ground the year before. They sprouted just fine. So the seeds weren’t the problem—it was the way I was going about it.
The seeds have to sit for a long time before they break down; that delay prevents premature germination. Natural abrasion and environmental wear provide the scarification part. This is required so they won’t germinate during a quick warm-up after a frost or freeze. If they germinated then, the next frost or freeze would kill them and a whole generation would be lost.
Nature built seeds with a way to sense when it’s time to sprout. It takes months of being out on the cold, damp ground—going through freeze/thaw cycles and wet/dry periods. This not only breaks down the hard outer coating but it also triggers the internal biology of the seed—the stratification part. By the time winter is over and the temperatures warm up enough, the process is complete and the plants will have a decent chance of survival.
So how do we trick the seeds into believing they have been outside all winter? We use cold, moist stratification and manual scarification—which involves nicking the seed coating so moisture can get inside.
The second part is easy. You can use sandpaper to gently rub off the coating, or a clean, sharp knife—like an X-Acto—to nick the outer shell. This breaks down the shell and will allow moisture to enter and get things started.
The first part—stratification—is easy too; it just takes a little more patience.
These are the steps required:
• Start by soaking your seeds in room-temperature water for about 24 hours. This softens the seed coat and tells the seed it’s time to wake up.
• Grab a handful of peat moss, vermiculite, or even just a paper towel. Get it damp—not dripping wet, but like a wrung-out sponge.
• Toss the seeds and the damp material into a plastic zipper bag. Label it with the date and the variety (trust me, you’ll forget which is which by March).
• Pop the bag into the back of your refrigerator and leave it for about 60 to 90 days.
Keep an eye on the seeds—some may start to germinate. If this happens, you'll have to plant them right away. Otherwise, once the time is up, get the seeds into the ground and you will be amazed at how fast they germinate and grow.
A couple of things to note: You may have heard that it’s best to keep your seeds in the freezer. While this may help preserve the seeds and keep them viable longer, it may also cause freeze damage. It also does nothing to help with stratification. The constant cold temperature coupled with the very dry air of the freezer isn’t what it takes. The seeds need a moist and cold (not frozen) environment for this to work.
The second thing is a personal pet peeve of mine. Seed companies don't always mention which seeds need cold stratification. How many times have you purchased seeds—especially flowers—only to plant them and not have any come up? Guess what? A lot of seeds that are sold, especially for native plants, require that stratification period in order to germinate. If they don’t get it, they will either sit there and rot, or won’t come up until the following year.
Echinacea (ek-uh-NAY-shuh) or Purple Coneflower is a perfect example of this; milkweed is another. I can’t tell you how much money I’ve spent on seeds and ultimately wasted because I didn’t understand stratification or the fact that the seeds I was dealing with needed it.
The best practice is to research your seeds beforehand; knowing whether they need a chill or a nick will save you a lot of guesswork. The extra effort required will go a long way toward your overall success and satisfaction.
Stratification and scarification: a lot of gardeners have heard these words, but many don’t really understand what they mean or why they matter. I sure didn’t at first. I learned the hard way—by trial and error and a few failures.
One year, I decided I was going to save all the seeds from the muscadine grapes I ate and grow myself a whole new batch of vines. I treated them just like the seeds I save from peppers, tomatoes, and squash: cleaned them, dried them for a week or so, and planted them. Sounded like a solid plan…but not a single seed sprouted. Not one.
I figured I’d either made a mistake or ended up with defective seeds. I shrugged it off and moved on. Then, months later, I noticed something interesting: little grape seedlings popping up all around the original vine. These were seeds that had simply fallen to the ground the year before. They sprouted just fine. So the seeds weren’t the problem—it was the way I was going about it.
The seeds have to sit for a long time before they break down; that delay prevents premature germination. Natural abrasion and environmental wear provide the scarification part. This is required so they won’t germinate during a quick warm-up after a frost or freeze. If they germinated then, the next frost or freeze would kill them and a whole generation would be lost.
Nature built seeds with a way to sense when it’s time to sprout. It takes months of being out on the cold, damp ground—going through freeze/thaw cycles and wet/dry periods. This not only breaks down the hard outer coating but it also triggers the internal biology of the seed—the stratification part. By the time winter is over and the temperatures warm up enough, the process is complete and the plants will have a decent chance of survival.
So how do we trick the seeds into believing they have been outside all winter? We use cold, moist stratification and manual scarification—which involves nicking the seed coating so moisture can get inside.
The second part is easy. You can use sandpaper to gently rub off the coating, or a clean, sharp knife—like an X-Acto—to nick the outer shell. This breaks down the shell and will allow moisture to enter and get things started.
The first part—stratification—is easy too; it just takes a little more patience.
These are the steps required:
• Start by soaking your seeds in room-temperature water for about 24 hours. This softens the seed coat and tells the seed it’s time to wake up.
• Grab a handful of peat moss, vermiculite, or even just a paper towel. Get it damp—not dripping wet, but like a wrung-out sponge.
• Toss the seeds and the damp material into a plastic zipper bag. Label it with the date and the variety (trust me, you’ll forget which is which by March).
• Pop the bag into the back of your refrigerator and leave it for about 60 to 90 days.
Keep an eye on the seeds—some may start to germinate. If this happens, you'll have to plant them right away. Otherwise, once the time is up, get the seeds into the ground and you will be amazed at how fast they germinate and grow.
A couple of things to note: You may have heard that it’s best to keep your seeds in the freezer. While this may help preserve the seeds and keep them viable longer, it may also cause freeze damage. It also does nothing to help with stratification. The constant cold temperature coupled with the very dry air of the freezer isn’t what it takes. The seeds need a moist and cold (not frozen) environment for this to work.
The second thing is a personal pet peeve of mine. Seed companies don't always mention which seeds need cold stratification. How many times have you purchased seeds—especially flowers—only to plant them and not have any come up? Guess what? A lot of seeds that are sold, especially for native plants, require that stratification period in order to germinate. If they don’t get it, they will either sit there and rot, or won’t come up until the following year.
Echinacea (ek-uh-NAY-shuh) or Purple Coneflower is a perfect example of this; milkweed is another. I can’t tell you how much money I’ve spent on seeds and ultimately wasted because I didn’t understand stratification or the fact that the seeds I was dealing with needed it.
The best practice is to research your seeds beforehand; knowing whether they need a chill or a nick will save you a lot of guesswork. The extra effort required will go a long way toward your overall success and satisfaction.
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