Seed Germination Basics
Plant seeds are an incredible piece of natural technology. Seeds possess varying degrees of dormancy which allow them to preserve themselves through unsuitable conditions and then grow when conditions are favorable. Seed germination is the process of breaking a seeds dormancy by providing the correct favorable conditions. Some seeds have stronger dormancy than others that can occur for a variety of reasons; from a thick seat coat(Snake Gourd, Bitter gourd), to germination inhibiting compounds located within or around the seed(Lotus), and other inhibitory methods. Some seeds require exposure to cold, or even urine/Urea(Sandalwood, Bodhi) in some cases to germinate!
Many of these requirements tend to coincide with a symbiotic relationship with an animal/condition that naturally occur in their habitat. For example, animals chew on thick coated seeds(mechanical scarification) or stomach acids eat away at some seed coats(chemical scarification). The need for cold(stratification) is usually related to the seeds needing to experience winter before growing in the spring. In these cases, it is usually necessary to mimic these conditions to germinate these types of seeds.
We highly recommend starting a majority of our varieties indoors to ensure a successful growing season. It is important to remember that India has a much longer growing season than 90% of the United States. While we select our varieties to be best suited for growing outside of India, starting them indoors will give them the head start they need to ensure a long fruitful harvest. Starting seeds indoors will also allow you to provide more consistent environmental conditions to ensure strong germination.
Preparing Seeds for sowing:
The paper towel method is a commonly used technique that can help you easily start many different types of seeds. This method involves placing seeds in a wet paper towel that is then enclosed in a resealable plastic bag until the seeds germinate. While this can be a reliable, simple method, it is not without its drawbacks. For very tiny seeds, this method is impractical, and it is also important to monitor for fungal growth on the moist paper towel, as this can actually end up killing your germinating seedlings. This method typically works bests for moderately sized seeds that do not have too thick of a seed coat.
Seeds like Bottle gourd, Ridge gourd, Moringa, & Gongura, should be soaked in water for 12-24 hours prior to sowing to help reduce germination time and increase success rate.
In terms of the paper towel method and soaked seeds, we recommend lightly drying the outer coat of the seeds, after soaking, prior to sowing to help minimize the risk of fungal growth.
Seeds like Bitter gourd and Snake gourd must be mechanically scarified to ensure consistent germination. This involves nicking, filing, scraping, or clipping away a part of the outer seed coat(without damaging the embryo within), typically prior to soaking in water for 24 hours. The scarification process helps water penetrate the thick seed coat more readily to break the dormancy.
Seeds like peppers and eggplant can be optionally soaked(while bearing in mind the risk of overly wet seeds), but they can also do just fine by being sown directly in starter cells.
Leafy greens, cucumber & okra can be directly sown in soil. (Okra and most greens can be planted directly outdoors when it is warm enough).
Planting seeds in soil:
After the seeds are prepared according to their species, it is important to have the appropriate supplies to sow your seeds. We recommend keeping the following items in your seed starting arsenal.
- Seed starting trays(with humidity cover!)
- Sterile Seed Starting soil mix
- Seed germination mat
Seed starting trays help manage your planting depth, minimize soil waste, and keep adjacent plant roots from competing with each other. A humidity cover in our opinion is an absolute must! It is important to remember we are germinating tropical seeds in a non-tropical environment. A humidity cover will help recreate a tropical environment and keep your soil from drying out during the germination process.
Lack of humidity can lead germination rates to be slow and/or inconsistent. If you soil dries out too much during germination, it is possible for your seeds to briefly germinate and then die before they can penetrate the soil surface.
Seed starting soil is an important part of getting consistent results in seed germination. Seed starting soil is more sterile and fluffier than potting or garden soil. Potting soil is generally pretty sterile, but it may contain bigger pieces like wood chips, etc. that may keep small seedlings from being able to penetrate the soil surface. It is also more likely to become compacted than seed starting soil. Compacted soil can also keep seedlings from germinating properly. Both of these factors can also lead germinating seedlings to dying before they can penetrate the soils surface.
Garden soil is absolutely NOT for seed germination! It is to be used for your outdoor garden beds only! Garden soil often contains fungal substrates(which are beneficial for more developed plants), but can be deadly to germinating seedlings. Many people erroneously use garden soil to germinate seeds.
When in doubt, just remember these mixes were all aptly named. Seed starting soil is for starting seeds, potting soil is for pots, and garden soil is for your garden.
What we recommend is lining starting trays with potting soil at the bottom of your trays and using seed starting mix for the planting depth of your cells. The benefit of this is that seed starting soil basically has no nutrition(which helps keep it free of competing microbes), where as potting soil does. Using this type of blend will give you the sterility and fluffiness you need to germinate your seedlings, while still providing some nutritious soil below to allow your seedlings to stay in the starter trays a little longer and establish themselves before first transplant.
Ensure to mind the planting depth of your seeds when sowing. Too deep and your seeds may never find their way to the top(it is possible for your seeds to germinate and grow in the wrong direction). Similarly if you plant your seeds too shallow, the seed may not get enough warmth/moisture to stimulate germination. The depth will vary based on the seed type.
After planting seeds, ensure to lightly cover with seed starting soil. Ensure not to push down too hard. We even recommend using a spray bottle to thoroughly, but gently water your trays without risking compacting the soil, or sloshing the seeds around. If it does not offend your sensibilities, you could even use a dilute fungicide spray as a preventative measure prior to placing on a germination mat.
Seed germination mats apply a gentle bottom heat that is within a safe range for seedlings. These mats can lower germination time and increase germination rate. Heat is known to accelerate chemical and biological processes. It is important to remember these mats can speed up seed growth just as much as they can speed up the growth of competing microbes. If using a mat, it is doubly important to ensure you are using clean supplies, and are mindful of overly soaked seeds. If not used correctly, a mat can actually inhibit your results by exacerbating "damping off" conditions.
After you have planted your seeds, covered, and placed in a warm place, it is important to be patient. You should not disturb the soil while waiting for germination, and you should not lift the humidity cover too much. You should check regularly to ensure the soil is moist(but not too wet!) and without fungal growth. (Fungal growth can pop up quickly with big white fuzzy looking growth and then visually disappear as it enters another phase of its life cycle, which could lead you to miss it if you do not monitor your seedlings). This is why "damping off" conditions can be silent killers of your young garden.
Once the seeds germinate, ensure they are under light. Put the light as close as you can to the humidity cover so the seedlings do not stretch too much trying to find light). Etiolated seedlings are not ideal and can make the rest of your gardening experience more difficult.
As they continue to grow, you can open the vents on your humidity cover to slowly acclimate them to the environment. You can eventually remove the cover for increasing amounts of time until the plants are acclimated to their environment.
You will need to perform a similar acclimation process when you transition the plants outdoors. This process is called "hardening off", and is essential for not shocking your seedlings when you transition them from inside to outside. Much like the humidity cover, exposure to outdoor temperatures and direct sunlight must be done gradually and increased incrementally.