Fredrick is an expert gardener, plumber, and author of farming guides. He loves to write about pest control, fish farming, and beekeeping.
Tomato seeds germinate easily, but accordingly to my own experience, they can completely fail to sprout if they are not exposed to the right environmental conditions. Practices like using a starting mix and treating your seeds can help with germination, but they are not enough to achieve a good germination rate.
In this article, I will discuss the reasons for tomato seeds not germinating. These seeds take a maximum of 10 days to germinate. So if your seeds haven’t sprouted after this number of days, read on to know what could have gone wrong.
1. You Watered Your Tomato Seeds Excessively
Overwatering makes the starting mix to waterlog causing the seeds to rot. It also prevents the seeds from getting enough oxygen thus hindering germination. You could have therefore applied excess water to your seeds causing them to die instead of germinating.
2. You Watered Them Inadequately
Tomato seeds need enough water to break the outer coating, and also to initiate the metabolic processes which are important for germination. Therefore, if you didn’t water your seeds adequately, these processes didn’t take place and probably the seeds died.
3. Your Seeds Were Exposed to High Temperature
For tomato seeds to germinate well, they should be exposed to a temperature in the range 70–80°F or 21–27°C. The crop will not sprout if the temperature is above 95°F or 35°C. If your seeds were exposed to this level of temperature or a higher level, then it could be the reason they didn’t sprout.
4. They Were Exposed to Low Temperature
Very low temperatures also don’t favor the germination process of this crop. Things like frost and snow cause very low temperatures, and you should avoid sowing when they are occurring. If you planted the seeds when the temperature were 50°F (10°C) or below, then it could be the reason they didn’t transform into seedlings.
5. They Didn’t Get Enough Oxygen
Seeds need oxygen to respire aerobically and for the metabolic processes to take place. Things like too compact starting mix or waterlogging can prevent seeds from getting enough oxygen. If you used a growing medium that was not well-aerated, then it could be the reason there was no germination.
6. You Sowed Them at a Wrong Depth
Tomato seeds are small and they shouldn’t therefore be planted too deeply. The right depth is a quarter of an inch or roughly a half of a centimeter. If you sowed your seeds deeper, then it could be the reason they failed.
7. They Were Eaten by Pests, Birds, or Rodents
Pests are the main culprit as they can enter the nursery without being noticed. If the nursery is a little bit far away from your house, it can easily be attacked by birds and rodents. If these animals are a problem in your garden, then they could have been the ones that destroyed the seeds thus causing the germination problem.
8. The Seeds Were of Poor Quality
Seeds that are diseased or that can’t tolerate mild environmental conditions are of poor quality. This kind of seeds do not germinate and if they manage to sprout, they grow into weak plants. If you sowed some cheap, poor quality seeds from the market, this could be the reason they didn’t germinate.
9. You Applied Excess Fertilizer or Uncomposted Manure
Excess fertilizer can 'burns' tomato seeds while uncomposted manure can dehydrate them thus preventing germination. If you planted your seeds right after applying fertilizer or manure, then it could the reason they didn’t grow into seedlings.
10. You Planted Non-Viable Seeds
Non-viable seeds have a zero germination rate. They are usually damaged as a result of poor storage or old age. Things like moisture and high temperature can easily damage tomato seeds while in the storage. As for the old age, tomato seeds can remain viable for a maximum of five years. So the reason why your seeds didn’t germinate could also be due to the non-viability issue.
In conclusion, other factors like low pH and high levels of soluble salts in the starting mix can interfere with the germination of tomato seeds, but it is highly likely that your seeds didn’t germinate because of one or more of the reasons discussed above. Therefore, I am hopeful that you will identify the exact reason(s) and try growing the crop again.
This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.
© 2021 Fredrick aka JS
Liz Westwood from UK on May 20, 2021:
This is a helpful article for anyone trying to grow tomato plants.