Definition of Cold Stratification:
Pre-treating seeds (cold stratification) is a simple measure you can take which will break a seed's dormancy causing the seed to be more ready to germinate. By subjecting the seeds to this pre-treatment you are really only providing them with the effect that mother nature would have had on the seeds had they been left to their natural course. However by applying the pre-treatment yourself in a controlled environment such as your refrigerator, you are speeding the process up and are better able to control and diminish factors detrimental to a seed's survival had it been left to make it on its own in the wild. By cold stratifying the seeds you are able to affect the time frame under which the seeds will germinate. By not cold stratifying the seeds (Strategy 2.) you will have to be content to accept nature's timeframe.
Cold Stratification, there's a couple different ways to accomplish cold stratification. The first is:
Mix your tree seeds in a clean plastic sealed or ziplock bag with thoroughly moistened vermiculite or peat and place in the bottom vegetable/fruit compartment of your refrigerator. DO NOT PUT IN THE FREEZER!!! It is important to thoroughly but only slightly dampen the vermiculite or peat. Excessive moisture can cause your seeds to mildew and grow moldy. You should not be able to squeeze any dripping water out of a handful of peat or vermiculite after thoroughly and uniformly moistening it. You can also completely moisten the peat then squeeze all the water out of it. I've also heard that placing the seeds in a damp paper towel will work also and placing them in the refridgerator. Also some people use moist white sand so they can keep an eye on the seeds and if any start to germinate in stratification they can be removed and planted.
You can also use a little fungicide when moistening your stratifying vermiculite or peat so as to help prevent mould or fungus outbreaks.
Some seeds will actually start to germinate during this process.
After undergoing the recommended period of cold stratification in your refrigerator the seeds are ready to be removed and sown in a warm situation in flats, the nursery bed or pot for germination. Preferably one should try to time this event to occur with Spring.
The Second Way to Cold Stratification is what I consider the easy way, to let mother nature do the work. To plant the seeds outdoors in a seedbed or nursery bed in the fall. The best time in the fall is about the time when the first frosts start to occur. If doing this it's a good idea to place mulch over the seeds to prevent them from being uncovered by the elements of weather (wind, rain, snow).
Also one last thing, all seedlings, whether grown in pots or beds benefit from good air circulation which wards off fungus growth and promotes sturdy stems.
And some recommendations growers should keep in mind when it comes to growing trees from seeds:
1.Seed germination is more of an art than a science.
2.Be patient when cold stratifying seeds, give them the recommended time and a few days or weeks extra for good measure.
3.You will find some batches of seeds sprouting before you expected and some later than expected.
4.Don't give up on any seeds that you planted but did not germinate immediately, this is to frequent of an outcome by growers and they will more often than not come up in the next spring. They usually just need more time to overcome their dormancy.
5.Pre-treated seeds like moist warm situations for germinating, not sopping wet cold situations.
6.Use clean or new soils and vermiculite whenever possible. Don't over water, over dampen anything.
7.You don't have to cold stratify if you don't want. Sow them in the Fall in a mulched seedbed or garden area for germination the following Spring. Its been working this way for several thousands of years.
Seeds can be stored in a fridgerator if not planting when the seeds arrive in the mail. Trees seeds will usually keep for a year or so in a refridgerator. The colder the seeds are kept, the longer they will stay viable. You do not what to freeze the seeds.
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