Why Should I Bury Tomato Plants & How Deep? Read This First


When I first heard that young tomato plants should be buried so that 2/3 of the plant is below ground, I had my doubts.  I started to wonder why this trick would work, and what it would do for the tomato plant.  I did some research to find out, and was able to find some good reasons to bury tomato plants.

So, why should you bury tomato plants?  When you bury a tomato plant deep, it will grow more roots on the stem, which helps the plant to absorb more water and nutrients so it can grow taller and produce more fruit.  Also, having less of the plant above ground makes it easier to protect young plants from late spring frosts and cold weather.  Finally, the extra roots provide more stability so that your tomato plants are less likely to fall over. 

As you can see, there are lots of good reasons to plant your tomatoes a little deeper in the soil.  We’ll go into more detail on each of these reasons, and then we’ll explain how to bury a tomato plant deep with detailed steps.

Why Should You Bury Tomato Plants?

Burying tomato plants to a depth of 2/3 of their height will allow the roots, and thus the entire plant, to grow stronger and larger.  This means that your tomato plants will yield more fruit each season.  Your plants will also be stronger and better able to resist disease and damage from the wind or sun.

Burying Tomato Plants Deep Helps Them To Grow More Roots

When you bury a tomato plant deeper in the soil, the part of the stem that is underground will start to produce more roots.  These adventitious roots grow out of small bumps on the stem.  You can see these bumps on the stem if you look closely, especially on larger, more mature tomato plants.

For more on adventitious roots, check out this article from The Spruce.

These adventitious roots will give the tomato plant a deeper and more extensive root system.  In turn, the roots can absorb more water and nutrients from the soil.

One benefit of a stronger root system is that the plant can cope well with a lack of water.  This helps to prevent blossom end rot, which can be caused by an uneven water supply to the tomato plant’s tissues.

tomato plant roots
This tomato plant has an extensive root system, which can help to cope with periods of drought.

A strong root system also allows tomato plants to grow larger and taller so that they can produce more fruit.  This will give you a bigger harvest during the season.

Finally, burying your tomato plants deep will prevent shallow roots that may come to the surface looking for water during a dry spell. For more information, check out my article on why tomato roots sometimes show above ground.

Burying Tomato Plants Deep Protects Them From Cold And Frost

Whether you buy seedlings or start your own plants from seeds, you will eventually need to transplant them outside.  If you don’t “harden off” your plants, you can damage them due to the sudden change in temperature.

When you bury a tomato plant deeper into the soil, less of the plant is exposed to the air above ground.  This makes it less likely that the plant will succumb to damage from cold due to late frosts or cold nighttime weather.

This is especially helpful if you happen to plant early, or if you get a long stretch of unseasonably cold weather late in the spring.  Burying tomato plants deeper also makes the part of the plant above ground shorter, which makes it easier to protect them using cloches or row covers.

cloches
A cloche can protect tomato plants from cold weather at night – but it does not need to be this fancy!

For more information, check out my article on how to protect plants from cold and frost.

Burying Tomato Plants Deep Protects Them From Wind And Storms

As mentioned earlier, burying tomato plants deep stimulates the growth of extra roots.  These extra roots help to provide stability, making it less likely that the plant will fall over during harsh winds or storms.  If you are worried about this in your area, check out my article on how to protect your plants from wind and storms.

wind sock
Wind can damage young tomato plants by drying them out faster in hot weather, or by knocking over more mature plants that are heavy with fruit. Staking or other support can help to prevent this.

A strong root system also makes it less likely that the plant will fall over due to its own weight.  Stronger roots mean stronger stems and branches, which allows the plant to support more fruit without falling over.

How To Bury A Tomato Plant

You are probably convinced that burying a tomato plant deep is a good idea.  So, how do you bury a tomato plant properly to stimulate the growth of extra adventitious roots from the stem?  Here are 5 steps to help you to get started.

Dig A Shallow Trench For Your Tomato Plant

If it is a sunny day, leave your tomato plants indoors or in the shade until this step is done.  Otherwise, you risk damaging them if the roots are dried out due to sun and air exposure!

Start off by digging a shallow trench for your tomato plant.  Make sure that the trench is wide enough so that the root ball (the entire root system) can comfortably fit inside the trench without damaging or bending the roots.  Otherwise, you risk stunted growth or death of the tomato plant.

Go down your row and dig a similar trench for each tomato plant.  Then, you can put any fertilizer, compost, or other additives that you normally would into each trench.

tomato stakes
If you try to put in stakes for your tomatoes after planting, you can accidentally damage the root system.

You may also want to put in supports (such as stakes or cages) now, to avoid damaging the root system of your tomato plants later.  For more information on why supports are a good idea, check out my article on why (and how) to support tomato plants.

Measure The Height Of Your Tomato Plant

Now it’s time to measure the height of your tomato plant.  Measure the height from the bottom of the root ball (root system) to the very top of the main stem on the plant. 

measuring tape
Use measuring tape to find the exact height of your plant (it’s ok if you eyeball it – I won’t tell anyone).

For the most part, you will want to wait until tomato seedlings grow to a height of 6 to 12 inches before transplanting them.  If you transplant a tomato seedling too late, then its root system will be too far developed.  At that point, it is much more likely that you will damage the root system during transplant. 

If you transplant a tomato seedling too early, then it may not be able to survive outside, even if you allow it to gradually harden off.  If you think any of your seedlings are too young or too small for transplanting, then wait a while until they grow larger before you transplant them.

Once you figure out the height of your tomato plant, tie a piece of twine 2/3 of the way up the plant.  For example, if the plant is 9 inches tall, then tie a piece of twine at a height of 6 inches above the root ball (3 inches from the top of the plant).

For more information, check out this article from Bonnie Plants on how deep to bury tomato plants.

Be careful not to tie the twine too tight around the tomato plant.  It is just a marker to help you when planting, and you can cut it off later if you want.

Cut Off Branches And Leaves Up To 2/3 Of The Height Of The Tomato Plant

Now, you should cut off any branches or leaves from the stem, up to where you tied the twine (that is, 2/3 of the way up the tomato plant).  Before you do this, make sure that there are still 2 or 3 sets of leaves on the top 1/3 of the plant.  If not, wait a little longer for more leaves to develop before you transplant the seedling.

tomato seedling
Remove the branches and leaves on the bottom 2/3 of the tomato plant before you bury it in the soil.

Any branches you bury will die anyway, and the leaves will not be able to absorb sunlight for photosynthesis if they are underground.  You can compost any branches and leaves that you cut off in this step.

Place The Tomato Plant In The Trench At An Angle

Put the tomato plant in the trench, with the root ball at one end and the top of the plant pointing up at an angle at the other end.  If you already put stakes into the ground, the top of the tomato plant should be pointing towards the stake.

Put some soil underneath the stem so that it has something to lean on.  Then, bury the root ball with the soil that you removed earlier.

When you are done, the stem of the tomato plant should be buried up to where you tied the twine earlier: 2/3 of the way up the plant.  Burying the plant at an angle like this allows the roots to sit in warmer soil, rather than cooler soil deeper down.

tomato plant
Right after you finish, the tomato plant will be leaning toward the stake at an angle, but it will straighten out as it grows up towards the sunlight.

Tie The Tomato Plant To The Support Using Twine

You can do this immediately or wait a few days, but it is a good idea to tie your tomato plant to its support (stake, cage, etc.) using twine.  Do this at height intervals of 12 inches (30 centimeters) as the plant grows.

This will help to prevent the plant from falling over due to the wind or its own weight once it starts producing fruit. For more information, check out my article on how and why to support tomatoes.

twine
Hemp, sisal, or jute twine will all work for tying your tomatoes to their supports.

Conclusion

By now, you know that it is a good idea to bury your tomato plants deep, and you know what the benefits are.  You also know how to take the necessary steps to make sure you plant your young tomato plants properly.

I hope you found this article helpful – if so, please share it with someone who can use the information.   If you have any questions or advice of your own about burying tomato plants deep in the soil, please leave a comment below.

jonathon.david.madore

Hi, I'm Jon. Let's solve your gardening problems, spend more time growing, and get the best harvest every year!

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