What Happens if You Plant Seeds Too Deep?

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Seeds planted deep in the ground may become weak seedlings or not germinate at all. If buried too far below the soil surface, the seeds may not receive the light they need to germinate.

If romaine lettuce seeds are planted too deep, they will germinate but not form seedlings. Planting depth is especially important for small seeds, such as lettuce.

So in this article, you’ll discover what happens if you plant seeds too deep. Let’s start.

Can seeds be planted deeper?

Deep planting is a common practice for gardeners.

They may overestimate the optimal depth for planting and bury the seeds too deep into the soil. Or they may have done so by mistake.

It is not easy to determine the exact planting depth because different seed types require different growing conditions.

Photo by Gelgas Airlangga from Pexels

What happens if you plant seeds too deep?

Seeds need the right conditions to grow. These include adequate sunlight, sufficient water, and nutrient-rich soil.

Most importantly, they should be planted deep enough to allow light and air to penetrate the soil and promote germination. Seeds have limited energy to break through the soil and germinate.

Thus, it contains the energy it needs to sustain itself until it is capable of photosynthesis.

Nature has a special plan for seedling growth. If the seed is planted too deep, this pattern is disrupted.

Slow or no germination

The growth stage of seedlings depends on aerobic respiration for energy. If there is too little or too much water, there is a risk that the seeds will not receive enough oxygen for germination.

Poorly calculated planting depth can make the situation worse, as oxygen supply is severely disrupted.

In addition, seeds planted too deep in the seed mix or garden soil have difficulty reaching the light. They weaken in the soil or are on their way to sprouting.

Some seedlings are planted too deep so that their shoots do not penetrate the soil. These seedlings lack nutrients, resulting in incomplete or no germination.

Larger seedlings can be planted deep, but smaller seedlings have little chance.

Loss of time and delayed germination

Deeply buried seeds take longer to break through the soil. Even when they germinate, they cannot be advanced far enough to get adequate air and sunlight.

This delay in germination and emergence can lead to other problems. Even if they survive, the effects of deep planting will extend throughout their life cycle.

Plant survival will be reduced, vigor will be weakened, growth will be reduced, and plantings will be reduced. This is the case in cold climates with short growing seasons.

How deep can the seeds be planted?

If you buy seeds in stores, you will find planting instructions on the package label. You can also find specific information on planting on the company’s website.

In the unlikely event that you receive seeds from a friend, you may not have the exact information at hand. You can also find information about seed varieties on the Internet.

The quality and vigor of the seed depend on several factors, such as the time of year and the type of soil. Unfortunately, the depth at which the seed is sown cannot be determined uniformly.

However, if you have minimal knowledge about seed placement depth, here are some basic rules of thumb.

  • First measure the diameter of the seed. The sowing depth should be two to three times the diameter of the seed.
  • Small seeds should be pressed into the soil and covered with a little soil.
  • Some species should be left uncovered in the soil.
  • If you grow plants indoors, you should buy special sterile soil for sowing new seeds.
  • Some seeds also need warm soil in certain temperature zones for germination. Using a heat mat or sowing seeds in a well-lit area can promote growth.
  • Seedlings usually need 14-16 hours of sunlight. If you do not live in a sunny location, you can use lamps as a substitute.

Can deeply planted seeds be replaced?

It seems that plants can be sown only once. But fortunately, there is a way to correct mistakes.

If you accidentally planted seeds too deep, there are two options.

Option 1: Leave them in place and wait for them to germinate.

Option 2: You can remove some of the soil covering the seed and let it return to its optimum depth.

The third option is after the germination phase. This is when you see that the seedlings are visibly growing and you are convinced that the planting was too deep.

Use a spade to gently lift the soil around the roots. You can then replant at the optimum depth. However, this is a delicate task.

Take extra care when replanting, as any damage to the roots will further hinder the plant’s growth.

What to do if you planted too deep?

If you have planted the seeds too deep, you do not have to despair. You may still be able to save some or all of them.

If the time between planting the seed and germination is too long, you may have buried it too deep. In this case, some of the soil covering it will need to be removed. (At this point it may be useful to mark the spot where the seed was planted).

If there is not enough time for the seeds to germinate, there are two options. One is to leave them for a while to see if they germinate.

The other is to scrape off some of the soil so the seeds don’t grow in as deep.

What to do if the seeds do not germinate?

If the seeds do not germinate at the proper sowing depth, there are several possible causes.

Temperature causes the seeds not to germinate

Soil temperature is one of the most important factors affecting seed germination. When the soil temperature is in the right range, seeds germinate faster and achieve a high germination rate.

Tomato seeds, for example, germinate in six days at a soil temperature of 30 degrees Celsius, and it takes 43 days at a soil temperature of 10 degrees Celsius.

At higher soil temperatures, above 90 degrees Celsius, many seeds do not germinate at all. However, lower soil temperatures are much more common.

Many seeds take more than a month to germinate in soils below 50 degrees Celsius. So make sure the soil is warm enough for the seeds to germinate.

When moisture prevents germination

Seeds also need moisture to germinate. If either is extreme, the seeds will not germinate.

If the soil is too dry, it won’t signal to the seed that it’s time to germinate. And if the soil is too wet, it will not receive enough oxygen for germination.

When sowing seeds indoors, a sprinkler can be used to keep the soil moist without overwatering it. If you are sowing seeds directly outdoors, you can use a drip irrigation system to keep the soil moist but not wet.

Air prevents seeds from germinating?

Seeds need oxygen from the air to germinate. Hard, compacted soil tends to lack air.

Excessive watering also causes air deficiency as air is lost between soil particles with the water. Avoid soaking the soil in which the seeds are planted, and make sure the soil is not too wet after watering.

Light prevents seeds from germinating

Some seeds, such as celery, dill, lettuce, and petunias, need light to germinate. If these seeds are buried too deeply (or not at all), they may not germinate.

What happens if they are planted too shallow?

Conversely, shallow planting can also be problematic. If the water evaporates too quickly, the seeds may dry out and not germinate.

In addition, even if they germinate in shallow soil, they may shoot out of the ground as they grow. For example, if peas are planted at shallow depths, they may emerge above the ground after germination.


G. (2020, July 22). What happens if you plant lettuce seeds too deep? Gardening Channel. https://www.gardeningchannel.com/what-happens-plant-lettuce-seeds-too-deep/#:%7E:text=ANSWER%3A%20Seeds%20that%20are%20planted,light%20it%20requires%20to%20sprout.

Hoose, S. (2020, November 17). What Is the Effect of Seed Depth on Plant Growth? Home Guides | SF Gate. https://homeguides.sfgate.com/effect-seed-depth-plant-growth-70012.html

J. (2022, February 24). Can You Plant Seeds Too Deep? (3 Things To Know). GreenUpSide. https://greenupside.com/can-you-plant-seeds-too-deep-3-things-to-know/

S. (2021, August 8). What Happens If You Plant A Seed Too Deep? ( Solved) : Homegrown Vegetables & More. https://vegderful.com/planting-seed-too-deep/

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