Pretreatment, Germination Strategy 1., dealing with dormancy.

Decide that you want to take a more direct hand in the germination process by forcing some break in the seed's natural dormancy (if any) through a pretreatment process you apply before actually sowing the seed. 

"Pretreatment" may mean no more then a water soak and for those seed species that have very little or absolutely no dormancy than a water soak is generally all that is needed after which the seeds can be sown in Spring/early Summer for immediate germination [providing that the pretreatment was effective]. (or they can be can be held dry, in their ziploks, in the refrigerator and sown in late Fall for germination the following Spring which properly falls under Germination Strategy 2. Nature's Way. They can be soaked prior to Fall sowing but it generally isn't needed as they will normally get all the moisture they will need out doors overwinter anyway.)

Dealing with Dormancy: Most tree species exhibit some seed dormancy.
Dormancy in seed species can be entirely absent or found to be generally one of two different forms of dormancy (embryonic or mechanical) or the seed type may characteristically exhibit both forms of dormancy. 

In anycase when deciding that you do want to do some of your own 'hands on' seed pretreatment you will proceed to
scarify the seeds if warranted and soak them before beginning to stratify the seeds and thereafter sow them for a 'forced' germination.
 *scarification (thinning, nicking, filing, sandpapering, or even subjecting the seed to repeated hot water soaks, or by slowly pouring near boiling water over them a few times..or any combination of these methods that may be sufficient to start the process of coat softening, coat rupture or coat break down)
* stratify (to store seeds in moist peat)

Embryo and mechanical dormancy:
However, with many tree seed species a pretreatment requiring a simple water soak is not in itself sufficient to overcome pronounced embryo dormancy and/or mechanical dormancy.
(*mechanical dormancy indicates a seed whose coat is very thick and or hard and/or impermeable and not readily able to soak up moisture or allow a developing embryo to expand inside its constrictive hard thick walls until such time as it breaks down somewhat or is helped to do so by the propagator using some form of scarification...- as such it can pay to help this kind of seed along a bit by scarifiying the seed coat - just don't damage the white embryo when doing so).
[*embryo dormancy refers to the seed's embryo requiring some form of trigger (usually cold moisture) inorder to make it respond.]
By the way; mechanical dormancy is not the same in all seed types, some can have a very thick but fairly soft coat susceptible to breaking down much faster than one whose coat is thinner but as hard as a rock while others can have very thick coats which are also rock hard...in the wild these different types will take longer or shorter amounts of time to break down depending on the conditions they get exposed to..

All that said the process of pretreating many species of tree seed and making it ready for germination is often no more than a simple three step operation involving a short period of cold stratification.

*Cold stratification: (the act of subjecting seeds to storage in a cold moist environment usually composed of mosit sterile peat for a length of time in order to overcome embryo dormancy.)

The majority of tree seed types usually have no more than a moderate embryo dormancy with slight mechanical dormancy requiring little or no scarification prior to soaking/cold stratifying. The simple act of soaking overnight will be sufficient to soften the coat.
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A quick simple three step process as used for Germination Strategy 1 - Artificial Pretreatment:

1. imbibe moisture, soak seeds 24-48 hours in room temperature water. (if you have a seed that has a coat that appears to be a little thick, stony or hard than as I have said it doesn't hurt to attempt a little scarification = thinning/breaching of the coat prior to the soak - you can always cut open a couple of your seeds to get a better idea of what you are dealing with in terms fo coat thickness.)

2. cold stratify: thereafter subject the fully soaked seed (usually 24-48 hours is enough) to a cold moist period as closely resembling mild winter conditions as possible. (this is done by placing the seeds in a clean new baggie with clean throughly moistened shredded peat in your refrigerator; - more on this point later.) Seeds with light embryo dormancy will only require 4-6 weeks of cold stratification while seeds at the other end of the embryo dormancy scale will need 4-8 months cold stratification or longer.

3. sow: remove seed and sow in conducive conditions; (more on what actually amounts to "conducive conditions" later).

Embryo dormancy is Nature's way of forcing the seed to only become susceptible to actual germination at a propitious time,..(namely early summer instead of late Fall going into winter.)

Seeds with mechanical dormancies (hard stony coat) are nature's way of spreading its chances across a wider span of time and conditions...extra hard coated seeds will each, in the wild, generally soften up and break down at differing rates of speed  (thereby allowing the next step of easier embryo expansion) due to differing circumstances each seed will find itself in (some may have ended up in mud...others in leaf mold, some in wet ground, some in dry ground, some only to get covered later, etc.).

Dealing with doubly dormant seeds - embryonic with mechanical.
Some seed types, particularly those with heavier mechanical dormancy and very deep embryo dormancy, tend to respond only after being subjected to an extended (or repeated) warm/cold seasonal cycle which can be artificially replicated by stratifying seeds in a warm stratification followed by a cold stratification. If you can help the seed along a bit by some effective scarification than the seeds may germinate after recieving only one cycle of warm strat./cold strat.. Effective scarification may also lessen the actual length of time needed for any warm stratification and help the chances of germination occuring after only one warm strat./cold strat. cycle. (when this type of seed is left to its own devices in the wild it generally won't germinate until it has gone through 2 or 3 summer/winter/spring cycles allowing the seed coat to break down and the deep embryo dormancy to be finally overcome.)
 * warm stratification is for all intents and purposes useful for advancing the softening of hard seed coats ...it is the same as cold stratification in all respects except one; you store the seeds/moist peat somewhere warm instead of cold for the recommended time. 
(warm stratification is equivalent to the seed sitting in warm soil/mud/leaf mold prior to winter's onset;  ie: often a whole summer season).

{I have been germinating tree seeds for a long time now and still have many germinating only in the 3rd, and 4th years after sowing despite having given them what I thought would be effective/sufficient stratifications...these are often very deeply dormant seeds and/or with very thick/stony coats....often nature can't be forced as much as might be hoped for.. the actual germinating conditions may have been less than stellar, and/or I wasn't as effective in my pretreatment regime as I had thought...take your pick!)

The late Fall sowing of seeds directly into a nursery bed or pot for eventual germination the following Spring(s) will naturally satisfy a seed's requirement for just about any and all cold stratification (providing of course that the natural conditions in question are such that the needs of the dormant seed are actually met). (for areas of N. America where there is very little semblence of a winter, deeply dormant seeds should be cold stratified in your refrigerator).
Nature's Method means you can forego the above outlined cold stratification in your refrigerator etc., as the overwintering of the seeds in the earth or a pot of potting soil out of doors (as long as the natural conditions are amenable/sufficient) can/will accomplish the same thing as refrigerator cold stratification . 
Usually the results are as good (and sometimes better) as those resulting from seeds which have undergone an artificial cold stratification and is a widely practised means of germination by professionals -not to mention Mother Nature. 
It goes without say that the springtime germinating conditions must be amenable/conducive too. Cold/wet springs aren't great.

If you are dealing with seeds that are recommended as needing some warm stratification prior to cold stratification than they should be sown a month or two, or a few months earlier than late Fall. These seeds often have thick hard coats (mechanical dormancy) and the recommended extra time in warm stratification for them is meant to allow them time in a warm moist situation inorder for their coats to begin to break down (in some cases it also has an effect on the embryo). It doesn't hurt to apply some scarification prior to Natural sowing this type of seed in mid Summer to early Fall as it will help the natural process along and likely lessen the length of time otherwise needed for effective warm stratification to have to occur.
(Depending on the species and variable depth/degree of dormancy and amount or lack of scarification applied, some seeds will sprout in the second and third Spring.)

We use both the artificial and the natural method and have no favourite really. If done right and you are lucky with seasonal conditions both are quite effective.

Question: I have these seeds and the instructions say they need xxxxx amount of cold stratification, I want to 
try the artificial germination strategy, can you tell me in a nutshell what should I do ?

Answer: "Get a bag of 'sterile' potting mix (usually shredded or milled peat) from your local garden center, - soak a handful or two of the peat in water and then squeeze out aproximately 95- 98% of the water, put the thoroughly but slightly moist peat in a new ziplok baggie, ....mix in the seeds (which you soaked overnight in room temp. water) ...mix the seeds up in the new baggie with the squeezed moist peat to ensure contact. .....Seal the baggie and put it in the bottom vegetable compartment of your refrigerator for the recommended xxxxx amount of time. After the recommended time take the seeds out and sow in a small clean pot of sterile potting soil (or nursery bed) to the recommended depth, tamp the soil down around the seed so it has good contact, put the pot somewhere warm (perhaps where it can get a few hours of  early morning sun, but not Texas midday scorching sun), keep the pot only slightly moist, never wet, ... sit back and wait (often 2-8 weeks). ........................Thats the short answer.

Many sources recommend using peat when cold stratifying seeds in the belief that peat is naturally highly sterile and pathogen free. This is true to some extent. However one should not use previously used peat or 'soiless mixes' because they are most definitely no longer sterile. 
Using peat or 'soiless mixes' which have not be fully squeezed of excess moisture will often lead to an outbreak of fungus or mold growing on the seeds during stratification. Excessive mold/fungus, if left unchecked, can cause injury to the seeds and interfere with the stratification process.
Again, when using peat to stratify seeds, acquire a newly bought bag of clean and dry, milled or shredded peat, or the sterile potting mixture known as "ProMix" (or similiar). These products are cheap and commonly found in most garden centers. Do not use old or used peat from the garden. Usually the number one reason for the unrestricted growth of fungus, bacteria or mold during the stratification process is excessive moisture in the peat.

Very Important Tip: A seedling cannot and does not need or use a lot of water, it therefore does not need to be sitting in sopping wet soil or even wet soil, the soil should only be kept slightly moist, in a warm situation where air movement on and around the pot and seedling is fair to brisk, and the pot and seedling is not frying in the midday Summer sun. This seedling care instruction is perhaps the most important tip a novice can get as it is where most make their mistakes. Do not disregard it!

You may find it easiest to thoroughly moisten your stratifying medium (peat and/or vermiculite mix) by applying either the straight water or a fungicide/water mixture to the 'medium' by using a spray/spritzer bottle. (If you use a horticultural fungicide than just follow the mixing instructions found on the bottle and mix it in with your water in your spritzer bottle). Keep spraying and mixing the peat until you have gotten the mositure consistency needed

If you are pretreating many seeds (hundreds) you should spread your seeds/stratification mixture into a few different baggies rather than putting them all into one baggie-that way if you do have a fungus outbreak it may be restricted to just one baggie of seeds.
If you forego the use of fungicide and just use water to moisten your peat than keep a closer check on them.

If you do eventually have an outbreak of mold or fungus, it is not a calamity, ...simply remove the tree seeds from the peat and wash them thoroughly with some dish soap and rinse ( I would thoroughly wash and rinse twice...use hottish water) and/or after washing the seeds you can respray them with your fungicide/water mix (so as to kill the mold/bacteria), using a fungicide/water mix is better than just using soap and water given the choice; place the seeds back in
a new baggie with new moistened peat. Do not re-use any of the old materials. 
Always keep the ziplok baggie sealed otherwise the medium will dry out quicker than you may think..an opened baggie will also allow pathogens to enter. 

The occurance of a little bit of mildew and/or fungus is not a problem and is often in evidence-however if it becomes aggressive and unrestricted in its growth than take the necessary measures outlined above. 

Again, remember that it doesn't hurt to give the seeds/peat mixture a spray of moisture once or twice part way through the storage period especially if the mixture appears to have dried up a little which does seem to happen. Remember, -the seeds do need moisture and must be in contact with moist peat during the storage. You can take the stratification baggie out now and then and shake the mixture up to change contact areas between seeds and moist peat.
It is a good idea to check your stratifying seeds on a regular basis for either fungus or germination. If any tree seeds begin to germinate during the cold stratification storage simply remove them and sow. (sow them just below the surface as you would normally. If it too cold to put them out of doors then sow them in a small pot and keep it somewhere warm where air is in circulation and they can get some early morning light)

Tips On Sowing and Seedlings:
Once the seeds are finished stratifiaction, remove them from the peat (and throw away the peat) and give them a good spray or wash of your fungicide/water mixture particularly if any mold or mildew is evidence. You can also give the hole you are planting the seeds into a contact spray as well with fungicide/water mix. If you are dealing with very small seeds you can sow 2-3 seeds per hole.

All seedlings, whether grown in pots or beds benefit from good air circulation which wards off bacteria and/or mold/fungus growth. Strong air circulation also promotes sturdy thicker stems in seedlings. Again, if the potting soil is too wet and/or cold, the seeds can either rot in the soil, or if they make it to seedling stage bacteria can and may attack the stem at its most vulnerable point where it enters the soil (where bacteria is often most prominent in poor conditions)- the seedling will choke/rot at that stem point and eventually fall over. This outcome is known as "damping off". Too cold, too wet, little or no air circulation and bacteria all add up to produce this outcome. 
Conditions conducive to promoting good germination are the exact opposite of "damping off" conditions; you want to have good air circulation and the pot should be kept where it is in or subjected to a warm situation during the day and only slightly moist. The seeds need to have warmth in the daytime.(ideally the nightime has warmed up considerably as well)..seeds can't be expected to germinate if they are continually subjected to cool wet conditions.
Furthermore while the soil is kept moist...its upper 2-3 inches should not be allowed to dry out to the point where it is completely absent of any moisture whatsoever.

*For the most part we find common comercially available sterile potting soils (often referred to as "soiless mixes") to be  adequate. Soil should be tamped down around the seed so that they are in good contact with soil and able to wick moisture from the soil.
Using a potting soil which is described as being sterile ("PRO-MIX" or similiar) to sprout your seeds in will aid you against possible problems with "stem rot" and "damping off": 
Because 'damping off' problems are much more likely to occur if air circulation is poor, letting your seeds and seedlings germinate and grow outdoors in the wind and sun warmed earth is often advantagious. If you feel your earth is still pretty cool getting the pots up on something that is warmed by the sun can help...like your deck or stone wall, etc.,
While in no way necessary if you have a cold frame or green house they can be used to advantage.

Some partial, screened or light shade is beneficial for seedlings as they are susceptible when young to withering and damage from unremitting strong or direct midday sun. Japanese Maples (and most maples) for instance are particularly sensitive and should be grown out in good dappled or screened shade. As they get older their sensitivity to direct midday sunlight is lessened.
Providing some dappled, or lightly screened shade will also protect your seed bed  from "frying' in the extremes of the sun as well.

Protecting The Seed Bed: Unprotected Seed Beds and Pots.
Most tree seeds need only be planted 1/4 to a 1/2 inch deep (depending on size) in order to germinate (exact depth is not exceptionally critical). If you plan on planting your seeds outdoors open to rain in a nursery bed, or garden nook bed or pot then plant them a little deeper to about 1/2 to 3/4 inch because the disturbance caused by heavy rainfall has a strong tendency to turn the seeds up. Keep a check on the seeds and push them back in if they do come up. This is very important..if they get turned up and then fried/dried out from the sun the next day your progress will have been retarded if not destroyed.

Where seeds may be sown in the Fall for natural germination the following Spring you should lightly mulch your seed bed as it  provides protection against heavy rains turning the seeds up in the winter... you should remember to lighten or remove completely all the mulch cover in the Spring, -if any seedlings are seen breaking through the soil's surface remove all mulch entirely if any has been left on. 

When to Sow/Germinate?
We are often asked: "When is the best time to germinate seeds?" Of course the best time for seeds to actually germinate is in Spring/Early Summer as then they have the whole summer to grow on. That being said, we often have many seeds that end up being sown and germinating right up into late Summer with no problem: (In anycase you will find that tree seeds often have a timetable of their own no matter what you do). 
If you live in colder zones, it can help to pile leaves or straw around first and second year seedlings to give them a little winter and wind protection. Shelter seedlings from prevailing winds, etc. Seedlings in pots can be allowed to go dormant and thereafter stored in a cold shed or garage to over winter.
If you intend to germinate naturally those seeds recommended as needing only cold stratification, than sow your seeds in the late Fall-approximately the time around and before frosts are starting to occur-there are no exact times for this but warm weather should be over. (You can also give the seeds an overnight soak before sowing if you are in areas where drought occurs in the fall)

Another query we often get is:, "Can I start my seeds and grow the seedlings indoors? over the winter?". This can be done provided your light source is sufficient (very strong!) and you subject the seedlings to strong air circulation (use a fan). If the seedlings do not get both of these requirements they will exhibit spindly growth and will have a difficult time when eventually transplanted to the garden.
It is during the seedling stage that the need for strong air circulation is greatest for the prevention of stem rot etc.,-once they have passed the immediate seedling stage than strong air circulation is not as important but will always enhance stem/trunk girth.

**Quite often seeds recommended as needing only a short (4-6 or 8 weeks) cold stratification will germinate sporadically after receiving only a water soak before sowing-however the germination rate cannot be relied upon to be as initially high, even or unified as the rate of those that receive the recommended short length of cold stratification.

How Long Does it Take For The Seeds To Germinate After Sowing?
This differs from seed to seed, specie to specie, and most particularly on how good the conditions are during the germinating phase (soil warmth, temperature variations, amount of moisture in the soil, etc.) and is dependant on how effective any pretreatment may have actually been prior to sowing-that being said it usually ranges between 2 or 3 to 8 weeks, late stragglers are common as are "hold outs" to the following Spring. If pretreatment was not sufficient or effective enough to break dormancy, some or all seeds can "hold out" until the following Spring. Don't give up on them. We have seedlings popping up here as late as five years after sowing. Its a good idea to mark any spots where you may have poked seeds down so you don't forget where they are or disturb them later.

Fertilization Of Seedlings:
Simple rule of thumb! Don't over do it. If the seedlings - trees are growing in a rich soil with sufficient finished organic matter mixed in than they really won't need it-otherwise once a month with a light dose of any balanced fertilizer is fine. Don't fertilize late in the season or your trees will go into winter with "soft" growth which is susceptible to damage. You need only fertilize when the soil has warmed up.

Garden Products
The best place to buy fertilizers, tools and needed garden accessories is at your local garden center or nursery where you can support your local economy and also be able to purchase well known major brands that were manufactured in North America and thereby be sure of how the product was made and correctly manufactured with quality ingredients instead of fertilizers that have been remixed and than re-labeled somewhere along the line. The same holds true for 're-labeled' and/or 'no-name brand' discount type garden tools/implements with the possibility of them having been imported from cheap labour/forced labour regimes with poor human rights records/child labour issues). Steer clear of so-called species "specific" fertilizers, "speciality" bio-chemical additives and other similar items for ammending soils etc., they are unnecessary "retail gimmicks". A simple balanced fertilizer, if needed, will always be sufficient. The best way to ammend/improve soils for better roots, water retention etc., as many will know is to simply turn in liberal amounts of finished organic matter, including some lesser amounts of bone meal, clean sand and friable earth. 
If you start out with or continually build a rich soil using these components you won't really need fertilizers in anycase. 
If you are in water logged areas get your tree up on a mound to shed water better.
The best place to get books on gardening is at your local library (and/or University extension library service)...their catalog is always huge and the books are free after all.

A Few Key Points:
Seed germination is a bit of an art and a green thumb and experience can help.
Pretreated seeds like moist warm situations for germinating-not wet or sopping wet cold situations.
You will quite often find some batches of seeds sprouting before you expected and some later than expected.
Be patient when cold stratifying seeds-give them the recommended time and a bit more for good measure.
Always use clean/new potting soils and pots.
Don't over water your seeds or seedlings! Watering from the bottom where flats or low pots in trays are or can be used for germination is effective as it can ameliorate overly wet soil surfaces that can be caused by watering from the top..
Remember that pots need more frequent waterings then nursery beds as they dry out quicker.
Terra cotta pots should be soaked before using.
Give your seedlings half/quarter shade from the sun - many deciduous types cannot handle full sun when seedlings.
You don't have to artificially cold stratify if you don't want to! Sow them in the Fall in a mulched bed or garden nook for natural germination the following Spring(s). (remember to mulch for protection from disturbance)
Don't give up on any seeds that you planted but did not germinate immediately-this is a frequent outcome and they will more often then not come up in the next Spring-they usually just need more time to overcome their dormancy.
Plant as many Lilac & Rose seeds as you can-your nose will really be glad you did when you sit in your garden in the evenings later on down the road! :)
Take a walk in your City Park in the Fall and gather tree & shrub seeds for free-you will likely be amazed at how many old and wonderful species your City Parks probably have! (City Hall usually has a tree species map too, with each tree wearing an identifying numbered metal tag.)
(Wait until the seeds have fully formed/filled out before you harvest.)

Storing Seeds For Later Usage

When storing seeds for sowing or stratification at some later date be sure to store them as they are in their sealed plastic ziploks so as to keep them air tight and dry and place in your refrigerator to keep cold. Many species of tree seeds can be maintained in viable condition this way for a number of years provided they were prepared correctly to begin with (as in correctly "banked"). 

**Trees are usually quite forgiving when it comes to what kind of soil they will tolerate. However they don't do well in soils that are at one extreme or the other in terms of composition (too much sand or too much clay) or extreme PH or especially constantly water logged, so steer clear of planting in really wet areas. If your transplant spot is on the wet side get the tree up on a mound. Try to amend your soils when possible with organic matter. Do not plant seedlings too deep if or when you decide to transplant them to a final spot-what ever root depth they had going while in the nursery pot should be maintained when they are moved if not raised a little bit higher. 

Further Reading Material:
"Plant Propagation: Principles and Practices" by Hartmann & Kester.
"The Reference Manual of  Woody Plant Propagation" by Michael Dirr.
 
 

If you have any questions regarding the germination process please email us at: 
angelgrove@nf.sympatico.ca
The Angelgrove Tree Seed Company (c.1993)

Trees grow remarkably fast from seedlings. Seedlings will often catch up to and surpass 3, 4 and 5 year old grafted clones, so that by age 10 or 12 the seedling is quite often a much bigger and more vigorous healthy tree. 
We have seen quite a few sorry looking re-potted pot bound and/or poorly grafted expensive store bought 3 and 4 year old clones sit and do nothing for many years on end after being brought home and transplanted with the tree trying to grow back into its butchered roots and/or get over a transplant shock, and/or deal with a poor graft. The seedling, having never hit a growth set back grows vigourously from the start.
When a transplanted 3 - 5 year old tree is subjected to a shock set back for what ever reason it can often take quite a few years for it to really get going again.