E0048 | Cold Stratification of Seeds

Welcome back to another episode of the Homegrown Liberty Podcast, this is episode 48, and today I’m teaching you all about how to cold stratify seeds for planting in the spring! This is super timely right now as we are headed into winter and for some of the seeds you might want to start it could take months of cold stratification to get their germination parameters met for sprouting. So if you’re wanting to get a bunch of tree seedlings planted in the spring, then now is the time to start! Why do we stratify seeds? Most seeds have built-in dormancy mechanisms that prevent them from germinating before a good season for growth has arrived. These germination prohibiting mechanisms keep the seed dormant through times of drought, or harsh conditions. Some of these systems keep them dormant through fall when temperatures are cool, there’s adequate moisture and otherwise it’s perfect growing conditions. This prevents the seed from germinating shortly before killing frosts arrive in winter. It can also keep them dormant through a warm period in spring and prevent them from sprouting too early. Because these systems exist, we as growers must sometimes artificially or pointedly supply the seeds with all the things they need to successfully and consistently germinate. We have to mimic nature, or at least be aware of the plant’s needs so that we can supply what it needs to grow and thrive! Stratification is... The process of breaking seed dormancy and promoting germination. Mostly what we’re talking about today is going to be Cold Moist Stratification, but some seeds need a combination of warm and moist and cold and moist, or sometimes there is need to alternate several times to replicate what happens in nature. Look up requirements for each species you intend to start from seed. It’s easily found online or in reference manuals. If you want to go the free route, just type into google’s search feature “stratification requirements for (insert species name)” For example, to find stratification requirements for apple seeds, type in “stratification requirements for Malus domestica” or for peaches, “stratification requirements for Prunus persica” but if you want specific information that is reliable, you must use the binary nomenclature or the scientific name. If you don’t know it, then just type into the google search feature “(latin) or (scientific) name for X” and it’ll probably be the first result. Now that you know the scientific name for the genus and species, you can look up the germination needs for free! How does it work really? Well the seed coat may be thick and hard and need to be softened by consistent moisture for a certain amount of time. There could be germination inhibiting hormones present such as abscisic acid. The seed coat might be thick and hard enough to prevent oxygen from getting to the embryo and thereby inhibit respiration, and keep the seed in a dormant state. The short answer is that cold stratification softens the seed coat, leaches out hormones, allows moisture and other elements into the seed and signals that it’s time to grow. Some seeds need a certain amount of light, some need a particular temperature range, some need to have their seed coats damaged by fire, or the digestive process of an animal to trigger the growth response. So by using “Cold Stratification”, we can simulate winter conditions and this one method is probably the most commonly needed when it comes to breaking seed dormancy. That’s why I’m talking about it first! What kinds of seeds is this appropriate for? Generally, temperate climate tree and shrub seeds will benefit from cold stratification, and a lot of the perennial herbaceous plants will also. This is generally not necessary for annuals because they are designed for quick growth. So specifically if you’re looking at a perennial, especially a tree or shrub, you should check to see if it needs stratification trea...