Common Mistakes When Sowing Seeds

12 April, 2025

Planting seeds is a relatively simple process: Bury the seeds in the soil, add water, heat, and sunlight, and in most cases, the seeds will germinate. The issue is that most of us carry out this process indoors due to space constraints in cities, where there isn’t as much land as in rural areas.

Urban gardening environments often lack sunlight, have unpredictable temperatures, and the roots are restricted by pots. Therefore, when sowing seeds indoors in a city setting, extra care is required. Here are some common mistakes to avoid when sowing seeds to ensure your plants thrive.

Lack of Light

This is one of the easiest problems to diagnose as it is also one of the most likely to occur. Remember that when planting seeds indoors, you are trying to simulate sunlight. When estimating the amount of light needed, this factor is often underestimated. The sign is very obvious: Your seedlings will be “leggy,” with stems that are not strong enough to support the plant’s leaves. The stems are usually bent, almost as if the plant has scoliosis. The seedlings may also lean towards the light.

The solution, of course, is to increase the light. Beginners often buy a grow light to illuminate their entire seedling shelf, whereas each tray needs 2000-5000 lumens. It’s not just the intensity of the light but also the duration: Seedlings require 14-16 hours of sunlight per day. Those lamps also need to be close to the seedlings. A suitable distance is between 15 and 20 cm from your seedlings.

If your seedlings are already too tall, there are a few things you can try. First, if they are tomatoes or peppers, you can bury much of the stem into the soil when potting up the seedlings or planting them outdoors, and this will solve many problems. If it’s another type of seedling, like cucumbers, they usually don’t need such a robust stem and will likely self-correct over time. Turning on a fan in the room and stroking the seedlings a few times a day will also help strengthen the stems.

Too Much Light

It’s actually quite easy to tell if there is too little or too much light for your plants. Just like us, plants can get sunburned. They develop scorch marks with almost white or yellow spots on the leaves at the top. These spots also lack any pattern.

Nowadays, seedlings are susceptible to many diseases, fungi, and viruses, so you may worry about whether this is sunburn or something else. The good news is that it doesn’t matter because the solution is the same: Cut it off. Sunburned leaves cannot absorb light or nutrients and cannot recover, so cut them off completely and let the rest of the plant recover. Obviously, move the lamp further away, at a sufficient distance.

Failure to Germinate

Among all the seeds you plant, some will not germinate. There are many reasons for this, but let’s consider the most likely causes. First, you may have buried the seeds too deep or not deep enough. On the back of every seed packet are instructions on the depth to bury them—and this is not a general recommendation. While the difference between seeds planted 3 cm or 3.5 cm deep may not matter, there is a huge difference between seeds that need to be lightly covered—such as carrots and most flowers—and those that are buried, such as tomatoes, peppers, cucumbers, and sunflowers. Another easy sign to recognize is: The bigger the seed, the deeper you need to bury it.

If the seeds have been in wet soil for too long and haven’t germinated, they have likely rotted. You just need to replant them.

Another reason could be that the seeds have expired. Every seed has an expiration date. The expiration date can be very short, such as onions, which are only good for one year. Experienced gardeners know that this is just a guideline; you can always test your seeds by trying to germinate them in the ground.

Too Much Water

Too much water, even if the plant survives, will prevent your seedlings from developing a strong root system. Just enough water is best, or even a little less, as long as the plant has enough water to survive, because it forces the roots to reach out for more resources, forming a stronger root system. Watering methods that allow seedlings to absorb only the necessary amount of water are ideal, such as watering from below, leaving a little water in the tray for the soil to absorb from the bottom up. But even when watering from above, you need slightly moist soil, but it should never be soggy.

Yellowing leaves or wilting are usually signs of overwatering. If the plant starts to smell foul, it’s likely that mold is growing in the water, which is also a sign of too much water. In these cases, the solution is to do the opposite and use less water. Your plant may recover or not. If you cut off any rotten roots or wilted leaves and stems, the plant may recover.

However, most seedlings will develop some green or white mold on the surface of the soil, and that’s not always a bad sign. If the plant is still growing well, you don’t need to do anything.

Insufficient Water

Wilting seedlings usually need water. In particular, tomato plants will start to tilt and literally look sad. This can happen towards the end of the watering cycle, which is a sign that you should water them. The plants immediately perk up again, usually within an hour or two of watering.

If the soil is completely dry, that’s never a good sign. Ideally, keep the bed constantly slightly moist. If you’re having trouble keeping the soil moist, consider watering from below, as this is a consistent method. The soil absorbs what it needs.

These are the most common mistakes made by beginners when sowing seeds. Hopefully, this article will be helpful to you.