There are two basic perennial seed germination techniques– you can do it indoors or you can do it outdoors. That’s pretty simple isn’t it. Here are the outdoor systems that work for most gardeners. Here are the outdoor systems that work for most gardeners.
Seeds sown outdoors get to experience the natural ups and downs of temperature ranges that stimulate natural hormone/growth cycles.
Plants are robust and healthy if sown far enough apart.
The gardener doesn’t have to have any special equipment or technique.
Having said that, the disadvantages to outdoor sowing are that outdoor sowing is variable and sometimes the results are unpredictable. Also, ants and mice enjoy perennial seed as much as they enjoy weed seed.
A Simple Video Showing You How I Sow Seeds
In the fall.
Use at least a six-inch size pot and cut the bottom off it. Larger pots are good. Smaller pots tend to be harder to water and care for.
Sink the pot into the natural garden soil so that only the top inch of the pot rim is showing above ground. Any circular pot or large pipe will do the same job. The objective is to isolate the soil inside the pot from the general garden soil.
Sterilize the soil inside the pot by slowly pouring boiling hot water over it. The hot water will kill all seeds in the pot. The more boiling water you use, the better. Use at least one gallon.
Allow the soil to cool.
Sow the seeds and barely cover them to protect them from mice/ants and drying out. Do not cover them deeply – only cover them so the seed disappears.
Walk away for the winter. Leave the seeds to act with Mother Nature.
Label the pot with a wooden stake written on with soft pencil. This will not degrade in sunlight nor fade.
In the spring, transplant those seeds that germinated.
If you didn’t get enough seedlings, leave the pot in place for one more summer/winter cycle
You can sow seed in early spring – it may or may not germinate in the summer. If not, simply allow to overwinter in place.
Seed that doesn’t germinate after two winter seasons is likely dead and should be tossed out.
Many gardener sow perennial seed directly into the garden where they want the plants to grow. This is an ideal solution for some plants. Hollyhocks are an excellent example, the seeds germinate readily so sowing them where you want them to bloom makes a great deal of sense.
The advantage is that you’ll have your plants where you want them.
The disadvantage is that the plants have to compete with other perennials and weeds – not to mention ants and mice who want to harvest your seeds for their own purposes.
My rule of thumb on this is that if I have a ton of seed and only need a few plants, then I don’t mind spreading the seed around and letting nature take its course.
If I’ve spent some money on the seed, I’d rather take care of that investment and sow in pots or indoors.
Indoor Seed Sowing
The Baggie Method
This method is really good if you have a lot of seeds you want to germinate and not much space. It works well and is used by many commercial growers and serious gardeners.
The disadvantage of this system is that you do have to pay attention to the process as there is little room for error once the seeds start germinating.
Obtain a good supply of baggies, one for each seed variety being germinated, and some damp but not soggy vermiculite.
Vermiculite is perfect for this task, it holds moisture well and it doesn’t rot.
A permanent magic marker and seeds round out our list. Put a handful of vermiculite in each baggy, then put the perennial seeds in the baggy and mix the two together.
How wet should the vermiculite be? If you squeeze it and water runs out, it is far too wet. It should be “just” damp. It will not lose moisture in the bag and the only function of the dampness is to keep humidity around the seed – not to provide moisture to the seedling.
Check this as sometimes the vermiculite will dry out – this seems to depend on the quality of the baggie.
An Alternative to Vermiculite
Some gardeners take tough industrial paper towels, dampen them and fold the seeds into them. This provides good moisture levels as well. I’m not a fan of this as I’ve sometimes missed the germination and I find the seeds growing into the paper towel. I’ve wrecked the seeds in transplanting. The solution to ruining the roots is not to try to take the roots out of the paper but to cut/rip the paper as well and plant roots and paper into the pot.
The reason I don’t like this system is that I have to manually unfold each towel to check on the seeds. It’s not bad when you have a half dozen seed packages but when you’re dealing with hundreds of packages, it can quickly become tedious.
Seal the bag so nothing leaks into or out of the bag.
Using an indelible magic marker, write the name of the seed and the date on the plastic bag and then tuck it into the vegetable crisper in the frig.
Writing the name on the bag is critical to prevent 1) the bag from being thrown out and 2) the contents from being eaten or fed to the cat 3) Remembering what exactly you’ve put in each bag.
Using a permanent marker is critical as well as others will disintegrate with the moisture in the frig.
You might find if you puff a breath of air into the bag and twist the top, you’ll have a balloon type of bag that is perfectly hard enough for writing with magic markers. Collapse the balloon before tying and storing in the frig.
Having the perennial seed in the frig is the first step in germinating perennial seeds
Now, as gardeners, we wait. That’s the hardest part of all so once a week, pull out every bag and check to see if the seed has started to germinate. Some perennial seeds are known as cool germinators eg. primula, and these will actually start to grow in the baggie. It only takes a few weeks to get these cool germinators started so check weekly after the first two weeks.
You See Roots
If you see a few roots starting to grow, carefully open the bag, remove the germinated seed and plant in a good quality potting soil.
Reseal the baggie back into the frig for further germination. In this way, cool germinators will continue to germinate throughout the entire 3 months the baggies will be left in the produce section of the frig. Do NOTshake up the baggies if this can be avoided as the tender root radicles will be destroyed if they are bent or bruised by shaking.
Seeds that are not cool germinators will often have the need for a period of moist stratification. This word “stratification” is simply another gardening word for staying cool and damp. Dr. Norm Deno has found that the chemical processes that change in a seed do so at approximately the 90 day mark. If the seed was dormant, after 90 days a chemical change takes place and the seed might get itself ready for growing.
After 90 Days Has Passed
After 90 days we take the seed out of the crisper and spread the baggie contents (un-germinated seed and vermiculite) onto a pot filled with damp potting soil. The first thing to do once the seed is spread is to write up a plant label for the pot. Nothing is so frustrating as to have seed germinating and not remember just what was in the pot.
Cover it very, very lightly with soil. Remember, perennial seed doesn’t require darkness to germinate. It requires steady moisture/humidity around the seed and a very light layer of soil will do this. In other words, don’t fret about whether the seed is 1/4 inch down or buried or ??? Simply cover it with a dusting of soil.
Keep this pot out of direct sunlight, slightly damp and reasonably warm. Note that the recommendation for perennial seed warm period is a soil temperature of 70F so you can treat perennial seed at this point in the process as you would an annual seed. Carefully put them on the growing heat mat or in their pots in the same aquarium as the annual seeds.
Most perennial seeds will germinate within the next 90 days. These seedlings can be potted up in their own pot, protected from the direct sun until they have 4 to 6 leaves and then given increasing amounts of sunlight or planted outside if the weather is right for planting.
If the seeds don’t germinate, there are two options.
One, the seed is dead and can be thrown out.
Or, two, the seed requires a double cold period to break its dormancy. This double dormancy requirement is quite common in many alpine perennials so the easiest thing to do is plunge the pot into the ground in the semi shade next to your house. Plunging the pot means sinking the pot up to its rim in the ground but leaving some of the rim showing.
Once the pot is plunged, it can be watered and if necessary weeded, throughout the summer. Weed carefully, make sure what you are pulling out is a weed and not a perennial and when pulling them out, try to disturb the soil as little as possible. Simply leave the pot in the ground for the following winter. It will freeze solid and if any germination is to occur, it will occur in the spring after the seed has had a good long winter rest.
If the seed does not germinate after this second winter, throw it out.
This system will work quite nicely on just about any perennial you care to grow. Some of the truly rare plants may be a bit more fussy than that but if you are growing Aquilegia jonesii or Erytrichium nanum, you don’t need this advice anyway. Just send me some seed.
I’ve started some rare plum and pear trees from Siberia using the crisper method and it is now my method of choice for the other rare tree and shrub seeds I have started to collect.
A simple system of germinating perennial seed
The simplest method however is to simply sow the seed on the top of a pot of soil, and cover very lightly with potting soil.
Label the pot and bury the pot; soil, seed and all in a snowbank to wait for spring germinating. Just make sure that the pot is upright and as the snowbank melts, the pots stay upright.
You will be surprised at how many perennials will germinate easily and simply this way. After all, that’s what they do in our gardens so why shouldn’t they germinate this way in a pot. I know quite a few specialist rock gardeners that use this method exclusively on their alpine seeds and if the seed doesn’t grow the first year, they plunge the pot and let it sit for another winter.
Germinating perennial seeds is relatively easy if you use either of these two methods. Of the two, the baggie and vermiculite is the easiest and the most entertaining.