As a beginner, nothing is more discouraging than realizing that your seeds have failed to sprout, especially after setting up your soil and planter and waiting for weeks. Sometimes it makes you think that you don’t have a green thumb. Anyone can successfully grow plants if they know what mistakes they are doing during seed starting and how to avoid those.
Seeds not germinating can be due to one or a combination of 11 factors:
- Inadequate watering
- Seeds were washed away
- Seeds are old
- Seeds planted too deep
- Fungi and bacteria
- Wrong time
- Improper storage
- Seed start mix
- Wrong container
- Unreliable sources
Let’s learn how to recognize and avoid them.
Table of Contents
- 1 Seeds Not Germinating, 11 Reasons And What To Do
- 2 Floating Seed Test: A Myth
- 3 The Light Myth
- 4 Can Seeds Germinate Inside A Fruit?
- 5 Organic Seeds
- 6 Takeaways
- 7 Sources
Problems with germination stem from a combination of the mistakes stated above. By far watering is the most common one among beginners.
Seeds are amazing (at least the viable ones): they store their own food supply. That’s why they can germinate with no light. Water is one of the essentials in starting the process of germination. During germination, seeds will tap into their stored energy for nutrition.
Seeds also breathe. The respiration rate for dormant seeds is low but this increases during germination.
Bad watering practices that cause failure in germination are:
- Overwatering and no drainage. Without drainage holes at the bottom of your container, the water cannot seep out and the seeds will drown having been deprived of oxygen.
- Not enough water. Some seeds have a hard coat. When there is not enough water, the root, which is the first one to emerge, cannot break out because there is not enough moisture in the soil to soften the coat.
When the germination process has started just after a dry period (seeds not watered), the seed embryo will die and you will not see sprouts emerge.
My tip here is to avoid using a watering can that has only one simple hole as its water exit. Watering cans with a hose are way better tools to water seeds over those with a single big hole.
Indeed, watering through concentrated jets of water can affect the seed germination in two ways: a) the soil becomes compacted due to the water pressure, and b) the water pressure pushes the seed deep into the container. Either way, it gets harder for oxygen to reach the seed.
So, how much is enough water? The answer is not straightforward because different seeds have specific requirements. Here are the general rules.
- Choose well-draining soil as well as containers that have holes at the bottom so that excess water can seep out. Check out our full germination guide for more tips.
- Soak the seeds in a small amount of water overnight so that they already have enough moisture prior to sowing. This works well with larger seeds (such as peas) because the tiny ones (such as onions) tend to clump together.
- A better idea is to lay off the watering can for now and use instead a water spray bottle with a fine spray setting. This will prevent you from overwatering, disturbing the seeds, or pushing the seed deeper.
- It may be possible to recover seeds from overwatering if you let the soil dry out somewhat.
- Try the bottom watering method. To do this, place the seedbed in a tray with up to 1 inch (2 cm) water. When the soil is moist, remove the bed and place it in another tray to allow the water to drain.
- Placing your seedbed inside a clear plastic bag or covering the bed with a glass pane will help retain moisture in the soil. So you don’t have to keep watering.
Like food, seeds also have a “use by” date. In other words, they do not last forever. Seeds lose their viability over time. Old seeds will either have a slow germination rate or will not sprout at all.
1. Make a plan of the types of plants you want to grow based on your location and the space you have indoors.
2. Don’t be tempted to buy packets of seeds that are not in your plan just because they are on sale.
3. Start your seeds according to the information written on the packet and according to the plant’s needs.
4. Whenever possible, use freshly bought seeds.
5. Use up the seeds within the year or sooner.
6. Writer on the seed package the expiry date with a pen. Indeed, very likely over time the small print tends to fade.
Another reason why seeds do not germinate is that you’ve planted them too deeply.
Larger seeds can be planted deep while other ones need to be almost on the surface (like dill). This is because the volume of the seeds is proportional to the amount of energy stored. This, in turn, dictates how long the stem can grow beneath the soil before reaching the light.
A large seed has enough energy to develop a long stem underground while a small one will die midway if planted too deep due to its low energy content and small stem it can grow.
The proper planting depth is standardly printed on the packet. Planting the seed too deep will make it harder for the oxygen to reach the seed. On the other hand, there are some seeds that you can just place on the soil’s surface because they need lots of light to germinate.
- If for some reason you do not have “depth” information, a good rule of thumb is to bury the seeds to a depth approximately twice the thickness of the seed. Then lightly cover the seed with soil, and gently press so that the seed and soil get into contact with each other.
- As discussed previously in the water section, use a fine mist water sprayer or practice bottom watering to avoid inadvertently pushing the seeds deeper into the soil.
- If you suspect that you have planted the seed too deep, you can try to take out the seed and try planting it closer to the surface.
This reason goes hand in hand with improper watering. Seeds are planted closer to the surface. For this reason, when you use a watering can, the water pressure tends to push the seeds deeper into the soil, pushes it to the walls of the container, or you’d end up with no seeds at all because they flowed right out of the pot.
Solution: Solve this by using a water sprayer or doing bottom watering. Avoid strong jets of water.
Bacterial and fungal diseases are threats to plants. When an adult plant becomes infected, it can transmit such infection to the seeds. The most common pathogens that attack seeds and cause germination to stop are Fusarium, Rhizoctonia, Phytophthora, and Pythium.
What Soil Conditions Do These Pathogens Grow In?
Pathogens that might harm a seed’s development thrive in three soil conditions:
- Wet and cool soil: This encourages Pythium growth and spread.
- Wet and warm soil: It is where Rhizoctonia and Phytophthora thrive.
- Compacted soil: There is not enough airflow in the soil.
Disease management is difficult once it has started. The key idea to avoid this problem is to reduce their chances of happening.
- Watering regime: Test soil moisture before watering. Although a moisture meter, gives a more accurate reading, you can test the soil by sticking your finger in and feeling for moisture. Be careful not to push the seed deeper into the soil.
- Sterilize your soil: We have a full sterilization guide on the topic
- Plant good quality seeds: Overtime you might know good seeds providers
- Fungicides: Use according to the type of fungi that is in the soil.
Seeds can either be from summer or winter crops. Summer crops are sown in the summer and harvested before winter whilst winter crops are planted in the winter to be harvested in the spring. Examples of edibles you can grow in the summer are tomato, cucumber, eggplant, and lady’s fingers. Examples of winter edibles are broccoli, cabbage, carrots, and spinach.
Seeds need an optimal temperature range to germinate. Not atmospheric temperature but soil temperature.
Luckily most vegetables and fruits are able to germinate indoors at a temperature range of 65-75°F (18-23°C) which is possible in a warmed-up house during winter or through the use of warming mats. Here is our full germination guide for more.
Many seeds fail to germinate when exposed to temperatures that are either too low or too high. Successfully growing plants require an understanding of the effects of temperature on seeds. Your first point of reference is the seed packet itself because most seeds will have all relevant seed information printed on it.
Here is an example of 5 vegetables you can plant indoors alongside soil temperature requirements to germinate.
|Vegetable||Optimal Range °F (°C)|
The idea is to gently warm the soil from below. You can warm the soil indoors by placing the seedbeds near radiators, the top of your fridge, or over a slow cooker, as those things give off heat. However, in normal outdoor conditions in spring/summer this should not be necessary.
Before sowing, measure the temperature by inserting a soil thermometer 3 to 4 inches (7.6-10 cm) into the soil. Some gardeners use a kitchen thermometer in lieu of a soil thermometer (please don’t forget to wash it thoroughly after using it.)
If you don’t have a heat source consider investing in a seed heating mat like this. The advantage of heating mats is that you can adjust the temperature setting based on the needs of the seeds plus the temperature will stay consistent.
Seeds have a natural dormancy (resting time) to protect them from the elements. For example, some seeds start to germinate in the fields when the temperature changes from winter to spring. Sometimes at the first sign of warm temperatures, we start planting, forgetting that it is not the correct season. Indeed, the temperature might drop again (frost) causing the seeds to struggle or even die.
Solution: Make a plant list. In your list, identify which are winter and summer plants. Take note of the conditions they thrive best in. Then set up your indoor growing system accordingly.
Most of the time, seed packets will contain more than enough seeds for your small garden and you end up with a surplus. Seeds are usually quite stubborn. If you think about it, they are designed to lay on soil for a whole year after they drop from their parent plant waiting for the next year.
How To Properly Store Seeds?
To properly store seeds, I would recommend to
- Remove diseased seeds: Damaged and withered seeds are likely not viable anymore; remove those before packing your seeds for storage.
- Store in a cool dry place: If your seeds came in a laminated foil pack, try to keep the original packaging or buy some foil packs to keep them dry. Store sealed to avoid the risk of introducing pathogens.
- Store in air-tight containers: If your seeds came in paper packs, store those containers that have a tight lid.
- Label containers properly: Write the name, date stored, and the “use by” date so you don’t have to open the containers until you are ready to use the seeds.
- Don’t leave seed packets anywhere: Seeds even if inside an unopened pack can get damaged if left exposed to temperatures the seed cannot handle. In this case, the seed will shrink and dry out and will be unable to soak in water when you sow them.
- Ideal storage temperature: 40°F (4°C) with low humidity. This happens often when seeds are just forgotten in a garage drawer.
Can I Store The Seeds From My Garden?
Many professional or long-time gardeners do prepare and store seeds from their own harvest. There are advantages and disadvantages to doing this. One advantage is that you do not have to buy seeds of the same indoor vegetable next year. One disadvantage is overlooking the cross-pollination of seeds by nature’s pollinators.
Cross-pollinated seeds will not necessarily produce the same seeds as the parent plant. They might taste bitter, have a different color, or may not be as hardy.
Another factor to consider is seed preparation. Seeds from fleshy fruits and vegetables are prepared differently from those seeds that are not. It can be overwhelming for beginners. I do not recommend doing this in your first year of gardening.
The problem with sandy soil is that it leeches out water and nutrients quickly. Clay soil does hold water and nutrients well but it has a tendency to hold too much water. Clay also compacts quite easily during dry spells.
The 3 Qualities Of A Good Germination Soil
- It should be fine, uniform, and loose. This helps with aeration.
- The soil should be free of insects, weeds, disease pathogens.
- Capable of holding moisture.
Solution A] Soil Amendment.
For sandy soil, adding organic matter will help with water and nutrient retention. Adding and mixing organic matter to clay soil will make dried-out soil softer and easier to break. An effective organic matter is an agricultural manure or household compost. It seems overwhelming which is why the first year, I do not recommend using your own garden soil as a seed starter.
The more experience you have with gardening, the more you will learn what type of soil works best for your planting needs and your location. The best seed start mix is one that is rated for indoor plants because it has the right amount of fertilizer. Too much fertilizer can slow down growth or burn up your seeds.
Solution B] Make your own mix at home with our simple potting soil recipe.
Sowing directly to the ground is not an option for most people. Some people live in places where ground soil quality is low, plenty of constructional trash (bricks, glass) or even not accessible. You can try to amend the soil, or you can gain control through container gardening.
Fortunately, you can use just about any container when starting your seeds: used seed trays or plant pots, plastic cups, or things gathering dust in your basement that you can grow plants in. Whatever you end up deciding to use, there are 3 important things to remember when it comes to containers:
- Clean and Sterilize: Clean and sterilize plant containers thoroughly before reusing them to kill pathogens that can prevent them from sprouting.
- Container Size: The container must have enough room for the root to grow when it breaks out. For example, you can start seeds in egg trays or other shallow containers but you have to monitor and carefully transfer the plant into a deeper container when seedlings start to appear.
Some people plant in larger pots altogether so they don’t have to transplant. Generally, planting root crops in containers is not recommended. However, plenty of gardeners have tried this to varying success. If you want to do this, remember that the edible portion of root crops grows inside containers. Take that into account when shopping for containers.
- Drainage: Containers should have holes so that excess water can drain otherwise the seeds will get washed away or end up rotting due to waterlogged soil.
Tip: Buying containers
Starting gardening need not have to be expensive. Beginners do not necessarily have the equipment such as plant containers at the start of the gardening journey. Here are a few places where one can find inexpensive containers: 1) sales at the garden center, 2) yard and garage sales, 3) estate auctions, and 4) community sales.
If not you can even go with simple yogurt containers (the short ones) or the cardboard egg containers (just make sure to make some drainage holes). They can get a bit dirtier than the commercial alternative (especially the egg containers) but they are free.
There are many ways to acquire seeds. You can buy from your local nursery or garden supplies store, buy online, some exchange seeds with community farming groups, and some get it as gifts.
No matter how you acquire them, be sure that the seeds only come from reputable sources. Aside from the name of the plant, the packet should include all information such as packaging date, how and when to sow, days to maturity, soil temperature, spacing, etc.
Not every single review can be trusted so be sure to read plenty when you decide to buy seeds from Amazon or from anywhere online. Read the positive as well as the negative ones, they help to inform you about what you can expect based on their experience.
Take note of where the seller’s seeds are sourced. If this is not in the product description and not in the reviews, try the “Customer questions & answers” section.
I do not recommend using seeds that come in plain plastic bags. Do not just rely on the word of your relative or farmer friend that the seed is celery or carrot. People can forget what seed they stored no matter how long they have been gardening. If not, you could end up with either seed that does not germinate or unknowingly grow invasive species that are hard to control once they take root.
Lastly, when in doubt about germination, try testing your seeds on a piece of moist tissue paper and only start in plant containers after assessing the viability.
The floating seed test is a method of testing seed viability by placing a few sample seeds into a container with some water. The viable ones sink while the bad ones float. Many plant experts say this is simply a myth.
Experiments have been done with various floating and sinking seeds to disprove this myth and measure germination rates. In one of those experiments, lentil seeds were used. The result was that 75% of sunken seeds and 86% of the floating seeds germinated.
Many maintain that seedlings need a consistent amount of light for photosynthesis. However, the truth of the matter is NOT all seeds need light in order to germinate. In fact, most seeds need darkness to germinate.
As early as 1926, biologist Kinzel conducted experiments on 964 plants to find out which ones germinated under these conditions: a) under light, b) under total darkness, and c) which seeds germinated after a hard and light frost.
He discovered that 114 plant species germinated at temperatures above 60°F (20°C) in total darkness while 270 plants germinated at the same temperature under the light.
However, it’s not as simple as that. Plants do not grow in a vacuum therefore other factors have to be considered. For example, some plants in the same genus may not necessarily have the same light (or darkness) requirement in order to germinate.
Seeds can germinate inside fruits. This phenomenon is called vivipary and can be triggered by particular storage conditions.
Sometimes seeds will do weird things which can shock those who are new to cultivating plants.
Seeds have a natural adaptation not to germinate before the right time or inside the fruit but certain conditions at the time of the plant’s growth break down this tendency. The most common situation that results in vivipary is through improper storage i.e. subjecting the parent plant to cold temperatures while it is developing.
Organic seeds come from plants that were grown without using chemicals, any synthetic fertilizers, and without genetically manipulating the seeds. The labeling of seeds as “organic” follows a strict standard and is regulated by the US Department of Agriculture’s Organic Program.
1. Analyse your situation and combine the solutions as needed.
2. Not all seeds need light to germinate. You need not have to immediately shell out money for lighting equipment before starting seeds.
3. You can grow many vegetables indoors by staying within the optimal temperature range (or the seed’s sweet spot).
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“Seed Starting Tips” by n.a. in Vermont Community Garden Network
“10 Reasons Your Seeds Aren’t Germinating & How To Fix It” by Elizabeth Waddington (book)
“Indoor Kitchen Gardening: Turn Your Home Into a Year-Round Vegetable Garden” by Elizabeth Millard (book)
“Plant Propagation from Seed” by Diane Relf and Elizabeth Ball in Virginia State University
“From Container to Kitchen” by D.J. Herda (ebook)
“Sowing Seeds: Planting Seeds Indoors” by n.a. in New York Botanical Garden
“Seed Starting Tools & Tips” by Rebecca Last in Research Gate
“Soil Temperature Conditions for Vegetable Seed Germination” by Joseph Kemble and Kerry Smith in Alabama A&M & Auburn Universities
“Testing Seeds At Home” by A. J. Pieters in United States Department of Agriculture
“Seed and Seedling Biology” by Lee Stivers and Tianna Dupont in PennState University
“The Effect of Light on Germination and Seedlings” by David Batty in Thompson & Morgan
“Soybean seed and seedling diseases” by Dean Malvick in University of Minnesota