The Wonder of Seeds and Germination Posted on 26 Oct 19:12 , 8 comments
Growing food from seeds is AMAZING. It is truly an awe inspiring experience. These tiny seeds can grow to be huge plants, sometimes producing hundreds of pounds of food. Sometimes those tiny seeds grow a beautiful radish or flower.
Understanding Seed Germination
When you decide to grow from seed, you'll need to decide if you're going to start indoors or outside. In this article, we will explain the process of seed germination as well as indoor/outdoor seed starting requirements. We also have a tip using Cinnamon!
But first, what is germination?
In simple terms, it is the process of a seed developing into a plant. Germination usually occurs below ground, before the stem and leaves appear above the soil.
All fully developed seeds contain three basic parts, the embryo, endosperm and seed coat.
The embryo is the part of the seed that develops into a plant. It contains the embryonic root (radical), embryonic stem (epicotyl and hypocotyl), and one or two seed leaves (cotyledons).
The endosperm contains the starch or stored energy for the developing embryo and is the largest part of the seed, packed around the embryo.
The seed coat is the outer layer that protects the seed’s internal structures.
In order for a seed to germinate, there are a few important factors: Water, oxygen and proper temperature.
Water is one of the vital elements when starting plants from seed. Too much water and your seeds will drown or rot. Too little and they will either fail to germinate or die once they do.
When a seed is exposed to the proper conditions, water and oxygen are absorbed through the seed coat and cause the embryo cells to enlarge. If there is not enough oxygen present, germination may not occur. The most common reason for a lack of oxygen is too much water in the soil due to over-watering or flooding.
Temperature is a bit trickier. Temperature requirements vary between species, but the general guide is between 68 F and 86 F, but 77°F is optimum.
Sometimes, it's not just as simple as sticking a seed into the ground.
Planting depth matters!
Seed sowing depth has a key role to play in germination. If you plant seeds too deep, they may fail to germinate. Alternatively, if you plant them too shallow, you could expose tender roots at germination, or the seeds could even wash away entirely.
The general rule for seeds is two or three times as deep as the seed’s diameter. That means those tiny seeds can often be surface sown while those giant beans need to plant planted plenty deep.
We have several articles and videos about seed starting (posted below). Some seeds need light, others need darkness. Some seeds do better with a 12-24 hour soaking and some require cold stratification or scarification.
Cold stratification is an extremely easy process and once you’ve done it once, you’ll no doubt get the hang of it. The time you need to keep your seeds in the refrigerator depends on the variety, but 4-5 weeks should be a sufficient amount of time for most seed varieties.
Once there’s no more chance of frost in your area, take your seeds out of the fridge and plant as normal. The simple, quick process of cold stratification helps the seed germinate quicker and grow more readily in your garden bed.
DIY Cold Stratification
Coconut Coir or Sand & Water
- Place a 1/4 cup of coconut coir sand (or more) in a mixing bowl. Slowly add water until you can form a ball with the sand/water mixture.
- Add your desired seed amount to the sand. Mix thoroughly.
- Place sand/seed mixture in a ziploc bag or container and seal.
- Label the variety and date clearly on the bag.
- Place in the refrigerator for 4-6 weeks before planting. If seedlings start to sprout in the bag in the refrigerator, remove immediately and either plant in the ground or in pots until it’s time to plant outdoors.
Seeds That Benefit from Soaking in Water include:
asparagus, beans, carrots, corn, okra, parsley, peas, pumpkins, squash, beet and Swiss chard seeds
Seeds That Germinate in Cool Soil include:
arugula, broccoli, Brussels sprouts, cabbage, carrots, cauliflower, Chinese cabbage, collards, garden cress, kale, kohlrabi, leeks, lettuce, mustard, onions, parsley, parsnip, peas, radish, spinach, and turnips
SEED STARTING BASICS
If you read our online reviews on our website and social media, you'll see that customers report very successful germination rates with Mary's Heirloom Seeds. If you're not sure about growing a certain variety in your area, we are just an email away and we're happy to answer your seed or garden related questions.
If you are starting seeds indoors or in containers, it is recommended to use "sterile" seed starting mix or soilless medium such as coconut coir mixed with perlite.
A good seed starting medium should be fine, uniform, well aerated, and loosely packed. It also needs to be free of insects, disease organisms, and weed seeds.
As we mention above, too much water can reduce oxygen levels and kill your seeds. Not enough water can cause developing seeds/seedlings to shrivel up and die before they reach the surface.
Keep your soil/medium moist but not waterlogged.
Temperature was also mentioned above. If you are starting seeds indoors, there are several options to warm up your soil: above the refrigerator, in a greenhouse (preferably heated) or a heating mat.
This is an important factor. While some seeds need light and others need darkness to germinate, plants NEED light. When your tiny seedlings begin to emerge, they will need a light source. If you are starting seeds indoors, it is best to use a grow light or something similar that is very close to your seedlings.
The type of light you use will determine how close it needs to be to your plants. In general, a florescent should be 10-12 inches away, while an LED should be 24-36 inches away. These are just general recommendations.
If you use a sunny windowsill indoors, seedlings often become "leggy" and not very strong. Rotating them daily and using a fan on low can help.
Remember how I mentioned Cinnamon?
Damping off is a soil-borne fungal disease that affects seeds and new seedlings. Several fungi can cause decay of seeds and seedlings including species of rhizoctonia, fusarium and phytophthora.
The most common way damping off will present itself is when your plant stalks become water-soaked, thin and mushy, and fall over at the base and die.
The seedlings, especially the cotyledons (the first leaves produced) may have a kind of gray-brown color, and young leaves will wilt and turn from green-gray to brown.
There is no cure for plants that already have damping off. However, you can easily prevent the problem by providing good air circulation
Cinnamon is a natural anti-bacterial and is often used as a rooting hormone. Bonus, it's delicious and most of us have a bottle or two in our kitchen cabinet.
Once your seeds are planted, gently sprinkle cinnamon over the surface. If you are starting seeds in trays, be sure to "bottom water" and don't over-water.
My best advice is to plant more seeds than you think you will need. Some will be eaten by bugs, some might not make it after transplant ans some may not thrive. The remaining seedlings might feed you for years to come. Have patience, plant seeds and enjoy the experience!
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