10 Reasons for Seeds Not Germinating & How to Fix It

Seeds not germinating can be a frustrating experience for any gardener. You may have prepared the soil, carefully planted the seeds, and provided them with the necessary water and sunlight, but still find that they are not sprouting. There are a lot of common issues that cause this, and thankfully, several ways to fix it.

There is quite a learning curve when it comes to starting your own seeds. Instead of just transplanting plants when the time is right, there are several factors to make sure are fulfilled to get the best germination rates.

While growing plants from seed can seem a little overwhelming, it’s simply a process that we all learn as we grow. Soon, you’ll be germinating seeds like the green thumb you are. But, even the best gardeners in the world have seeds not germinating.

Let’s explore what can happen both internal and external factors, that keep your seeds from sprouting above the soil surface and how to fix it!

16 Reasons for Seeds Not Germinating

Frequently seeds will have poor germination rates due to improper growing conditions. If the environment is not just right, seeds will not germinate well, if at all. Thankfully troubleshooting and preventing germination problems is pretty easy.

1. Incorrect Temperature

Whether you’re direct sowing seeds outdoors or starting seeds indoors, the soil temperature is important.

In general, seeds germinate within a specific range of temperatures. Outside of this temperature range, some seeds will not germinate at all, while others will have poor germination rates. This is also true for the extreme temperatures of the range, close to the colder side or warmer side of the given range, you may have poor germination rates.

Many crops will germinate best around room temperature at approximately 60-75 degrees Fahrenheit, but this is not true for all seeds.

While germination may be low, some seeds, like radishes, carrots, turnips, and cabbage can germinate in soil temperatures as low as 40°F. Others, such as pepper seeds and tomato seeds, need warm soil at approximately 75°F to 85°F to germinate.

Other sides also require cold stratification to successfully germinate which is a period of cold typically followed by a rapid rise in temperature to mark the changing of the seasons.

Knowing the temperature range and whether or not seeds require a period of cold will go a long way to helping you understand what seeds need for successful growth. Much of this information is typically located on the seed packets, so make sure you’re checking that out to see what the seed needs.

How to Fix The Problem

First, make sure you’re checking the seed packet for the temperature range required for the seed to sprout. If your seed packet doesn’t contain this information, look it up in a gardening book or online from a trusted source so you have a good idea.

For seeds that require hotter soil temperatures, it’s best to start seeds indoors and utilize a heat mat, grow light, and humidity dome (which increase the temperature in the seed trays) so you can modify the soil temperatures to suit the needs of the plant.

For directly sown crops, you can lay black plastic over the garden to allow the sun to heat up the soil, or use a hotbed, cloche, cold frame, or other method to extend your growing season to keep the environment and temperature hospitable for successful germination.

Be sure to use a soil thermometer to keep an eye on the soil temps so you know you’re sowing at the right temperature.

2. Incorrect Seeding Depth

A common cause of seeds not germinating is planting at the wrong depth. Planting seeds too deeply can cause problems with how much oxygen a seed receives.

This oxygen is required until photosynthesis takes over, which means if it’s planted too deep, it may not be getting the air required.

A general rule of thumb is to plant a seed twice the depth of its size. So for tiny seeds, like carrots, for instance, they should be surface sown. For larger seeds such as pumpkin or bean seeds, they’ll be planted around 1″.

How to Fix It

Again, seedling packets typically contain this information. If they don’t, or you don’t have them, be sure to check out gardening books or online to see what depth you need to plant certain crops.

3. Incorrect Watering

Seedlings can be difficult to find the right balance of moisture for growing seeds and overwatering or underwatering are some of the most common causes for seeds not germinating.

Too much moisture 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.

Watering too much can also cause high humidity levels, which can cause damping off which we will discuss later in this article.

Of course, on the flip side, not having enough water can cause seeds not to germinate (or quickly die off afterward).

Seeds require moist soil for germination and only after they receive it can the metabolic processes required for successful germination take place.

Not only is water required for the cellular processes and enzymes to take place and release, but many seeds need water to simply break down the outer coating of the seed so that the plant can emerge.

How to Solve It

When starting seeds, be sure to begin with wet soil, not sopping, not dry. Well drained soil is your friend for most common garden crops. I recommend watering the soil before sowing the seeds. Then, water daily, or every other day, to keep the soil moist, but not drenched.

Make sure you aren’t watering too deeply that you wash the seeds away or push them further into the soil, but water deep enough to keep the soil moist to the touch and not dry.

4. Seeds Not Receiving Enough Light

Some seeds, particularly herbs, and some flowers, actually require light to germinate. If you plant the seeds too deeply, they won’t receive the light required for successful germination.

This goes back to the seed packet information. Many times it will tell you to surface sow, sometimes it isn’t specific enough for a novice gardener to know that the seeds require light, though.

For any packet that says surface sow, you can bet that it will require light to germinate. Any seed packet that says specifically they need light obviously will be surface-sown.

If the seed packet isn’t specific or doesn’t list planting depth, again a good gardening book, blog, or the like will help you figure out the depth.

How to Prevent This

Be sure you do your due diligence on seed depth requirements. Check seed packages to see what the listed depth is.

When germinating seed requires light, simply surface sow on damp garden soil or seed growing medium and then lightly sprinkle seeds on top of the soil. When watering, either water from the bottom or spritz the soil with water to not wash the seeds away.

5. Damping Off

Damping off is caused by multiple, common soil-borne fungi that develop due to moisture levels and humidity. It’s incredibly common when starting seeds early indoors or in greenhouses where light levels are low and humidity levels are often high.

Damping off may allow the seeds to germinate in patches and then they quickly wilt away or it may not allow seedling emergence at all.

Often you’ll see white mold on top of your soil or surrounding the seedlings that have emerged. This is a sign that your seeds are suffering from one of the multiple fungi that cause this problem such as Fusarium, Pythium, Phytophthora, and Rhizoctonia.

How to Prevent Damping Off

The fungi that cause damping off are present in the environment and often on and in multiple materials you may utilize for seed starting. While you can’t completely prevent it from happening, you can help reduce the risk of it happening.

Make sure all of your seedling trays and seed starting supplies are clean. If you have containers that damping off occurred last year, don’t use them again. You can also disinfect seed trays and starting supplies to help kill off any fungi.

Another problem can be that the fungi can be present in your seed starting medium. This is especially true of homemade compost as we generally don’t sterilize it. If you find that seeds started in your homemade compost are damping off, you can sterilize it.

Lastly, make sure you aren’t overcrowding or overwatering your seeds. Make sure the seedlings have good airflow and water adequately but not too to help keep humidity levels low.

6. Naturally Low Germination Rates

Certain types of seeds have naturally low germination rates. The genetic makeup of certain plant species makes them more difficult to germinate than others.

While having only half of the seeds or fewer germinate can be due to a problem, it could simply be that the germination rates for those seeds are low.

I recommend checking the seed packet, which will often contain the germination rate of the seeds or online to see what success others are having. You can also, if you have enough seeds, check germination rates yourself by testing seed germination in paper towels.

7. Pests Ate the Seeds

If no seeds have germinated and they were sown outdoors or even sat outdoors, a potential problem could be pests ate the seeds before they had a chance to grow.

We recently had this problem with corn. Something came in the garden and ate all of the seeds, not once, but twice, before we had anything sprout above the soil surface.

Pests such as birds, mice, moles, and rats are the most prevalent culprits of missing seeds but even pests such as earwigs can scoot off with seeds!

How to Fix It

While sowing seeds outdoors is necessary for many crops such as beans and peas, if you can start them indoors, it may be best.

If starting them indoors isn’t an option, you can try covering your seeds with row covers or mesh to prevent most pests from getting to them.

8. Overfertilization

A lot of people don’t realize that seeds are incredible little bundles of nutrients. They contain all of the nutrients they need to sprout and grow without any outside help (aside from water and light to start the processes).

If you are direct sowing, make sure you don’t just lay down fresh fertilizer as it may be too much for young plants or fresh seeds to handle.

If you’re starting seeds indoors, don’t fertilize anything until after the seeds have sprouted.

If you want to put manure in the garden, uncomposted, make sure to do that during the autumn so it has time to work its way into the soil.

Of course, rabbit and goat manure can be used fresh if you choose, but I don’t recommend doing it right before or after sowing seeds or even on young seedlings.

9. Expired Seeds

Seeds don’t stay good forever. How long seeds are viable varies greatly among types. That said, if stored properly, all new seeds will be good for a minimum of 1 year.

Some seeds will stay good for 4 years or so, others won’t stay good for more than that one year. Seeds such as onions, carrots, and parsnips are typically on that list of 1 year viability. Seeds such as cabbage, pumpkin, and tomato are known to last at least 4 years.

A lot of seed packets will have a “sow by” date on them. While this is not an actual expiration date, it is a general deadline that you should be mindful of. If you find that your seeds aren’t germinating or have very low rates it could just be that you have old seeds.

10. Incorrect Storage Conditions

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.

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.

Other Gardening Posts to Check Out:

• 10 Common Seed Starting Mistakes (and fixing them)
• How to Make Your Own Seed Starting Mix
• 8 Vegetables You Should Start Indoors