It’s a few weeks before spring, and gardeners everywhere are starting baby plants from seed. Germinating seeds isn’t usually a difficult process, and for most veggies, the process is quite simple.
For complete instructions for starting seeds, get the seed starting guide.
But what do you do if your seeds don’t germinate?
When seeds don’t sprout, you should always take time to evaluate what happened. So I thought it would be helpful to talk about the most common reasons you might have seed germination problems.
Some years our germination is a little patchy, and occasionally whole rows of seedlings will not germinate. It is important to keep up with our germination rate to evaluate our technique and seed health.
For us, a minimum acceptable germination rate is when at least 80% of our seeds sprout. But ideally, 100% of our seeds come up, so anything less than 80 or even 90% germination rate, and we start looking at what went wrong.
Easily keep track of your germination rate with these garden worksheets.
Learn the 5 fatal mistakes for germinating seeds
When vegetable seeds are not germinating, there are a few common problems that you should look for.
1. You used old seeds
The first thing to consider is whether the seeds were viable in the first place. If your seeds have not sprouted within the appropriate number days (this will depend on your seeds), then you may want to consider using a pen or pencil to gently dig around in your soil and find the seed.
- If you don’t find the seed, think back. Did you forget to put the seeds into the mix? Don’t laugh! It could happen!
- If you find the seed, take a good look at it. You may see that it looks just the way it did when you put it in the soil. In this case, the cause for a low germination rate might be that it was an old seed or not properly stored.
If you have some old seeds and are unsure of whether your seeds were viable, you can always sprout a couple of them in a wet paper towel to check prior to planting.
For new seeds or seeds you saved last year:
- When you saved seed, did you put them away without letting them dry completely? This can cause seeds to rot or mold.
- Were they exposed to extreme temperatures during storage? For example, if you left seed packs in your car over the summer. High temperatures over 90 can kill the plant inside the seed.
- Was the parent plant healthy? Seeds can harbor infection from the parent plant that may prevent sprouting, however, this is not usually the case.
2. You didn’t use new or sterilized containers
Disease issues can be a factor in seed germination. Think back to last year and whether you had any disease issues with your seedlings.
- Most plastic containers can be reused for several years, but they need to be sanitized.
We clean ours by submersing them in bleach water at the beginning of the season.
If you are looking for a bleach alternative, try the environmentally friendly bleach alternatives that use hydrogen peroxide as their active ingredient.
Fungal and mold infections are the most common infection from dirty containers. If infection occurs you will notice a fuzzy growth on the top of the planting medium.
- You may also see that a seed sprouts, but then rots at its base and falls over.
This is called damping off and is caused by a funal infection in your soil. A hydrogen peroxide or colloidal silver solution can help treat fungal disease on your tender plants.
3. Your technique is not right
- If you started seeds in any mix that includes non-sterilized soil from the yard, your seeds may have been affected by disease organisms in the soil.
In order to use garden soil for starting seeds, you should sift it carefully to remove sticks and clumps. Then bake it on a cookie sheet in the oven at 180 degrees for 30 minutes. That should kill most weeds and pathogens.
You’re better off using a seed starting mix. Seed starting mix is usually a soiless mixture that has a finer grain and is free of clumps, sticks, and pathogens.
- Did you plant your seeds too deep?
Planting your seeds too deep can cause problems with sprouting. You should also avoid pressing down on top of your seeds after you plant them. If the soil in your container is too compacted, the seeds cannot sprout or form healthy roots.
4. You didn’t provide the correct temperature
The temperature of your soil is of utmost importance in getting a good seed germination.
- Temperatures that are too high or too low can cause problems germinating seeds.
Given all else is equal, even tray germination requires even temperatures. If temperatures plunge at night, or peak over 100 for a prolonged period, seeds will either remain dormant or die.
- Did you leave the heat mat too high or too low?
Even when using seed starting heat mats, accidents happen. If you forget to put the temperature probe into the seed tray, the heat mat can overheat and cook the seeds.
Sometimes heat mats get accidentally turn off, or you forget to plug it in.
An alternative to the heat mat is to put them in a sunny south facing window or on top of the refrigerator. You can also use grow lights to provide heat above, and I have even seen people use rope lights to generate warmth.
5. You watered incorrectly
Seeds need to be moderately moist to sprout.
- Seed germination is highly dependent on watering. Too dry and they won’t get the message to sprout, too wet and they will rot in the dirt.
Very young seedlings are even more tender. Seedlings do best in what we call the “Goldilocks zone.” You know Goldilocks. She likes her porridge not too hot and not too cold, but juuust right.
- Tender seedling babies can’t tolerate drying out. While young, even a short dry period can mean death after the first wilt.
On the other hand, their tender roots will be the first victim of conditions being too wet. They can’t get the oxygen they need to carry about their business, and it will stunt or kill the seedling.
What other problems have you had germinating seeds?
If you’ve had troubles germinating seeds and this article didn’t answer your question, leave me a comment below. I’m happy to help you work out what’s going on.
Idris says
I am doing brinjal/eggplant seedling. I am in tropical country which is sunny/hot and humid all year long.. temperature in the morning or afternoon can reach 35°Celcius, and only 27/28°Celcius at night.
All my seeds of eggplant didnt germinate (15 of them) . We didnt need any heat mat, because we didnt have frost problem
Maybe you can advise on that.
Thanks in advance
Laura says
Hi Idris, How old are the seeds? If they’re more than 3 or 5 years old, they can be slower to germinate. Did they get watered correctly? They should never dry out or be soggy. How long ago did you start them? Eggplant seeds can take up to 21 days to germinate from seed. Their ideal soil temp is similar to tomatoes 75-85F (23-29C), is it that warm where the seeds are?
Tom says
Have you ever had peppers or tomato seedling leaves get stuck inside their hard seed coat after germinating? I have, and it is not easy to remedy once it happens. My solution to this which I have been using for 10 years is to plant the seed with the pointed end (root tip) UP, not down. When the seed root emerges, it makes an immediate U-turn downwards. What emerges above the soil is the middle of the seed stem in an inverted U shape. The leaves are still in the seed coat below the surface where it is still moist. Eventually the inverted U pulls the leaves up and out of the soil with the seed coat still buried. Works every time. Not so helpful on seeds that are difficult to tell which end is the root end (round seeds).
Laura says
That’s interesting, Tom. I have had some that emerge with the seed still stuck on the tips of the cotyledons. I can usually pull it off or it comes off on its own in a few days. I’ve never had them get completely stuck! Thanks for sharing your tips!
Erica says
Thank you for these tips. I am a novice gardener but can usually get a seedling to sprout. However, I cannot get strawberry seeds to sprout. I’ve tried 3 varieties, twice. Do you have any tips?
Laura says
Honestly, I have never grown strawberries from seed, but I know that they can take a really long time to sprout. This website seems to have some good tips: https://www.westcoastseeds.com/how-to-grow-guides/grow-strawberries/
anita says
I have a problem once the seeds have sprouted I am not sure when to transplant them and what soil to use next.
Laura says
Hi, Anita! When your seedlings have at least their first set of true leaves (the second set to appear), they can be transplanted. We use a 50:50 mix of seed starting mix and potting soil. After transplanting, wait a couple of weeks before setting them out in the garden. 🙂
Sophie says
My mother has been successful at germinating tomato seeds but the problem occurs after the two leaf stage . The plant just dies despite the soil being kept moist.
Laura says
Does it look like damping off-the seedling withers at the base and flops over? https://www.extension.umn.edu/garden/yard-garden/diseases/damping-off/
Sharon says
Here in Singapore, we are always warm but my house I stay, do not have much sunlight, I have a full length window, stayed on 14 floor but no sunlight comes in, I placed my seeds near this full length window but still the seeds dun sprout. Indoor our temperature is abt 25-30 degree C. Can advise what can i do? This time I try on cherry tomato seeds which I bought from a supermarket.
Laura says
Hi Sharon, water and temperature are the most important factors for germination. You can’t let your seedlings get dry in the early stages. For tomatoes, sunlight is necessary as soon as they sprout but should not affect germination. How long ago did you plant them? They can take up to 10 days.
Cherrie says
Hi! I’m new to gardening and in my country we reach 35c in late mornings or afternoon and around 28c in the evening. I started paper towel germinating method with sunflower, onions, and pepper seeds. Sunflower germinated in as fast as 2 days. How long will the others germinate? Or how do I know if they won’t germinate at all? How long should I wait? Thanks in advance!
Laura says
Hi Cherrie! Being totally honest, I don’t use the paper towel method for germinating seeds, but I do know that in the soil it can take up to 10 days for onions to sprout and peppers up to 3 weeks. When seeds are slow to germinate, it’s usually because they are old and/or the temperature is not right. Onions prefer slightly cooler temps than peppers (21c). Peppers can be kind of picky needing to be about 80F(26c). When it’s taking a while to germinate, make sure that they do not ever dry out. Curious why you’re using the paper towel method. Are the seeds old?
David says
Please my cucumber seeds in Lagos Nigeria fail to germinate, very worrisome
Laura says
Hi, David. Cucumbers love water. Did you make sure they didn’t get dried out?
Aparna says
My seeds grew well in time and healthy but stem is too long so they fall after sometime it’s difficult to water and give manure to such plants
Laura says
What are you growing? Where/how is it planted? How old is it?
Evelin says
its my first time, when I put my kit together and added my seeds, only a few germinated and others didn’t, should I take off the cover and just let the rest catch up or should I keep it close until they do?
Laura says
Hi, Evelin! You should remove the cover when: all the seeds have sprouted, it’s past the maximum days for germination (varies by plant type), or the sprouted seedlings are tall enough to touch the cover – whichever comes first. It’s not uncommon to have uneven germination. This is usually due to seed age, temperature of the soil, or uneven watering.
Colleen says
Thanks for this info! Maybe you can help me. I’m on day 5 after starting my seeds and don’t have anything coming up yet. I am brand new to seed starting. So, I started them in toilet paper rolls and they started unraveling (unable to tape them b/c I watered them) so I transferred them to styrofoam cups. Newbie mistake, forgot to put drainage holes (face in palm). I realized this the day after I planted them and was able to cut some holes in the bottom without disturbing the soil. However, I think too much water was sitting in the cup on day 1. The water drained on day 2. Do you think my seedlings still have a chance or could they be ruined from the water? Sorry for this super long comment!!
Laura says
Hi, Colleen! I think you’ll probably be fine, but we’ll just have to wait and see.
Colleen K says
This is my first time germinating seeds. I have a heat mat but it doesn’t have a thermometer it just raises the temp 10 degrees from outside air temp it says. I sowed my seeds yesterday in the greenhouse and put plastic humidity domes over the trays. Last night was supposed to dip to 40’degrees so I put an electric heater in there and about 1/3 of my trays are on the heat mat. Today when I went in it said the greenhouse was like 105 degrees and the soil feels hot to the touch. Did I already kill my seeds??? And if not should I just use the heat mats or forget the heat mats and use just the electric heater ?
Laura says
Hi Colleen. If the soil was over 100 degrees for a limited period of time and none had sprouted yet, you might be okay. We’ll just have to wait and see. Without a thermometer, a heat mat can get too hot and bake your seeds. I do recommend getting a thermometer and remove them from the heat mat until you do.
Tonya says
Hi! I’m new at this as well. How often do I need to water the seeds? Some sprouted but not all. Most I don’t see any signs of sprouting. My main question would be that if some that sprouted are now shriveled up and dry is there any chance of saving them?
I’m working with flowers.
Laura says
Hi Tonya! Unfortunately, if they dry up, there’s no coming back for seedlings. You need to check them every day. The soil should stay slightly damp, but you don’t want them soaked. Depending on the situation, they may need watering every day to every other day. Best of luck with the rest of your flowers!