You planted seeds only to discover germination rates were low to non-existent. It can make you want to throw in the towel, however, it’s important to figure out why your seeds aren’t germinating.
I am a huge proponent of starting your garden from seeds. There’s so much more diversity and plenty of places that sell heirloom seeds that you can support. This improves your sustainability (heirloom seeds can be saved) and helps to preserve varieties our ancestors worked hard to develop.
But what about when things don’t work out as planned and you plant the seeds and nothing, or very few, sprout? Does that mean you just don’t know how to grow seeds and you should purchase seedlings from the big box store or local nursery?
Nope. Thankfully, there are a handful of causes of low germination rates and they’re usually pretty easy to figure out. Get it figured out and often times you can fix the problem, or prevent it from happening again.
Causes of Poor Germination of Seeds
Frequently seeds will have poor germination rates due to improper growing conditions. If the environment is not just right, they will not germinate well, if at all. Too much of a good thing, or not enough, can cause seed germination rates to be low to non-existent.
1. Temperatures are Too Low
Whether you’re direct sowing some seeds outdoors or starting seeds indoors, the temperature is important.
Most common garden crops germinate best between 60°F and 75°F. That being said, this isn’t true for all seeds, just most. Some seeds, like radishes, carrots, turnips, and cabbage can germinate in soil temperatures as low as 40°F. Others, such as peppers and tomatoes, need the heat turned up to 75°F to 85°F to germinate.
This problem can be eliminated by utilizing heat mats, grow lights (that can increase the temperature inside seed trays), and even artificially heating the soil for direct sown crops by laying black plastic over the garden.
Cold frames, green houses, and milk jugs for winter sowing can also help create the correct temperature environment for successful germination.
2. Temperatures are too high
As I said, there is such a thing as too much of a good thing. While seeds need enough warmth to germinate, the temperature can be too warm.
When temps begin climbing above 85°F to 90°F seeds will often fail to germinate. This can be a problem if you’re starting seeds in the late summer in the garden. But it can also be a problem when you’re starting seeds indoors.
If your seed trays are near a radiator or stove… the soil temperature may rise too high. Move the trays to a cooler location without all that direct heat.
If you’re sowing seeds outdoors you can’t just move them, right? But you can try to provide them with some shade to decrease the soil temperatures enough to promote proper germination.
3. Too much water
Seedlings can be difficult to find the right balance of moisture for growing seeds and overwatering is one of the most common causes of low germination rates.
Too much water leads to compaction and water-logged soil (and seeds). Which means they can essentially rot before they even grow. It can also reduce the amount of oxygen available, which is essential for growth.
When starting seeds, be sure to start with damp soil (not sopping, but not dry) and when watering, water from the bottom of seed trays, not the top and only when the soil begins to dry out on top.
4. Not enough water
Again, finding the proper level of moisture for seeds can be difficult, but seeds require water in order to germinate and grow.
Seeds have to absorb enough water to start the metabolic processes that allow growth as well as break down the protective coating on the seed to allow it to sprout.
If the soil is super dry, then you don’t have enough water. Again, start seeds in moist soil and water from the bottom for the best results.
5. The seeds weren’t planted at the proper depth
Seeds need oxygen to grow and while over or under watering can cause a lack of oxygen, it’s usually planting seeds too deep that results in lack of oxygen.
A good rule of thumb is a seed should be planted twice the depth as its size. Tiny seeds like many herbs and carrots barely need buried (sometimes even surface sown) under the soil surface. Larger seeds like pumpkin seeds need planted fairly deep.
You can check the seed packet for planting depth requirements. If your seed packet doesn’t contain that essential information, you can check a gardening book or online to be sure you’re planting at the correct depth.
6. Something ate the seeds
If you’re direct sowing seeds, growing them in a greenhouse, or even a garage and nothing is germinating, it may be a pest problem.
Birds love to peck your freshly sown seeds out of the ground! Even mice, chipmunks, earwigs, and a multitude of other things will also take off with your seeds. Heck, we even had a chicken take off with our cloves of garlic one fall.
Some theft just can’t be avoided… despite your best efforts. But, if you’re direct sowing try using row covers to keep most of the pests detoured from thieving your seeds.
7. You over-fertilized
Hot soil will kill just about anything. So, if you just put down fresh fertilizer it may be too much for your little seeds to handle.
Seeds are pretty incredible, they contain all the nutrients they need to get themselves sprouted and going. Placing them in soil that has too many nutrients can kill them off before they even get started.
If you want to put manure in the garden, uncomposted, it’s best to do it in the fall so it has time to work its way into the soil. Of course, rabbit manure and goat manure can be used fresh if you choose, but I still wouldn’t do it right before, or after, sowing seeds or even seedlings.
8. Your seeds are too old
Seeds don’t stay good forever. How long seeds are viable varies greatly among types. That said, if stored properly, all seeds will be good for a minimum of 1 to 2 years.
Some will stay good for 5 years or so, others won’t stay good for more than that one to two-year span. If you aren’t sure if the seeds are too old, you can always test germination rates and see if anything sprouts before you dedicate yourself to germinating seeds that are simply too old.
9. The seeds weren’t stored properly
Proper storage is essential for seed viability. If you leave them out in the baking sun, let them get exposed to moisture, have them in a place with extreme temperature changes or just don’t store them properly, they won’t germinate, at all.
I utilize this seed storage and organization method and have had excellent luck with it. That said, mylar bags are another great option for seed storage, whether you utilize that particular organizer, stuff them in jars, or even a shoebox. The mylar bags will help keep the right conditions inside and the rest out.
10. The seeds weren’t pretreated
Some seeds need pre-sprouted, and others need cold stratification to germinate. Most seed packets contain this information, and while we may think we can ignore it, it’s best to follow the recommendations on the packet.
If your seed packet has no information on it, check gardening books, blogs, or even facebook groups to see how to properly sprout the seed if you don’t have experience growing a particular plant. That way you start off on the right foot and get things moving without wasting precious time and resources guessing.
Eventually, you’ll be able to troubleshoot and successfully grow all of the things from seed, if you desire to do so. Gardening is a marathon, not a sprint, and we’ve all had unsuccessful gardening endeavors. Just try, try again.
If you’re looking for ideas on how to reconnect with your food, nature, and the heritage way of life, you’ve come to the right place.
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