Your hydroponic or outdoor garden is ready, yet some of your seeds aren’t sprouting. Assuming your environmental factors are in check with respect to seed depth (1 inch at most!), temperature (68-86 F), and not too much or too little water, there are usually three reasons why this is happening: primary dormancy, secondary dormancy, or infertility. There is nothing you can do about infertility, but there is hope in the other two cases.
Primary Dormancy -
Primary dormancy is described as being a type of physical dormancy where the seed coat is too hard, which inhibits the seed from up taking water. Without the seed being able to up take water, the GA3 or gibberellins inside the seed that activate germination can’t tell the seed to start sprouting.
Secondary Dormancy -
When looking at secondary dormancy, this deals more with the internal workings of the seed rather than the outer layers. Secondary dormancy is typically due to the embryo not being fully developed, which obviously inhibits the process of germination. Sometimes the embryo can actually be fully developed, but other internal factors keep the seed from properly germinating.
Although these can be serious problems for growers, there are simple ways to overcome these types of dormancy.
Techniques to Help Your Seeds Grow -
The first technique used commonly is called
scarification. This technique can either be done by using a scalpel or straight edge blade and gently scraping the seed coat, or rubbing lightly with sandpaper or a file. Cut or scratch just enough so that you begin to see a lighter shade to the seed coat—this will be enough for the water to be absorbed. Another way to go about this technique is by chemically breaking down the seed coat by soaking the seeds in either warm water or sulfuric acid overnight. (Common household vinegar will do the trick.) This will soften the seed coat allowing water to enter the seed and start the process of germination.
If scarification doesn’t produce results you desire, a second strategy that can be used to break dormancy is called stratification. During stratification, a seed is placed into extreme cold and moist conditions for a period of time (usually a month will do but normally not longer than two months) that mimic the natural winter. The best way to do this is to store your seeds in a closed container within a moist medium in your refrigerator (40 F). Check periodically to make sure that the medium is moist yet not wet (just wet enough so that you don't see dry spots) and that the temperature is never freezing! You will want to take the seeds out after two weeks and put them in a cool place with little to no light. After about 12-24 hours, put the seeds back in the fridge for another two weeks. Do this three to four times to mimic the freeze/thaw cycle that plants go through in nature. Plant the seeds as you normally would once you’ve completed this process.
This article was written by Tom Feezel, Plant Specialist at Growers House (GrowersHouse.com