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I’m sure by now, most of us have heard about the wonders of burying your tomato stems deeply in the ground. But, if you’re anything like me, you’ve probably been curious if all that talk is true. Well, let me set the record straight for you.
Yes, tomato stems can and should be planted deeply to help them develop a strong and robust root system which is vital for the health and well-being of your plants. But, if you’re growing grafted tomatoes, do NOT plant above the site of the graft.
I’ll go over the two best deep planting methods as well as discuss how to plant grafted tomatoes as they need a little bit of extra care and attention.
Why you should bury your tomato stems deep
Tomatoes are an incredible plant for so many different reasons. One of those reasons is their adventitious root system. This means that they can produce new roots from their stem. But only if their stems come in contact with the soil.
By burying your tomato stems deep, you’re making it possible for new roots to grow from the stem. More roots mean a stronger root system and a stronger root system means a healthier plant.
Any plant with a strong root system will have an easier time taking in water and nutrients from the soil. It also helps to protect the plant from outside forces like the weather.
With a strong root system, your tomatoes have an extra layer of protection from something like wind which might otherwise blow them over.
If you’re also struggling with leggy tomato seedlings, then planting the stems deep can help to fix that legginess altogether.
How to transplant tomato starts
There are two different methods that people like to use when it comes to planting tomatoes with their stems buried. Here’s a rundown of both of them.
Deep hole planting
This method is pretty much exactly what it sounds like, you’re just planting your tomatoes into a really deep hole.
Your seedlings should be at least 6 inches tall before doing a deep planting but 12 inches tall would be even better. Shorter plants are difficult to plant deeply simply because there is not that much plant to put in the ground yet.
Before planting your tomatoes, trim or pinch off any of the lower branches that will be going underground. Once buried, the plant won’t need or be able to use these leaves anymore and will eventually grow new ones above ground.
You still want to leave the upper leaves on the plant or else it won’t be able to photosynthesize and will ultimately die.
How deep to plant your tomato starts will depend on how tall they are. In general, you should aim to bury about ⅔ of the plant underground. If your plants are already pretty tall, then your hole will need to be really deep.
Once you’ve put your plant in the hole, all that’s left is to fill the hole back in. When burying the plant, you don’t want any of the soil to actually touch the upper leaves that you’ve left above ground.
If the leaves are too close to the soil or even touching it, then you run the risk of introducing soil-borne diseases to your plant. Since tomatoes are extremely susceptible to disease, this can be detrimental.
After your tomato plants are buried, don’t forget to give them a good water to help encourage that new root growth. Try to water them close to the soil and don’t get too much water on the leaves. Wet leaves can, again, lead to some bad diseases.
This method of deep planting is similar to the deep hole method except you’re planting horizontally instead of vertically.
Now, I know what you’re thinking. Is it even possible to plant something sideways? Well, with tomatoes, it is! (Just another reason tomatoes are so incredible.)
To plant your tomatoes horizontally, you first need to start by digging a shallow trench. The trench should be about 6 inches in length.
If this is too long for your tomato starts because they’re not tall enough, then you can either wait until they get some more height, or opt for the deep hole method instead.
Similar to the deep hole method, go ahead and remove any lower leaves that would otherwise be buried underground.
Lay your tomato plant in the ground on its side and bury the stem. As you bury the stem, try to gently turn the top leaves up so that they’re in a more vertical position. Be very careful when bending the stem. If it snaps, your plant will die.
As I mentioned earlier, tomato leaves that are touching the soil are much more susceptible to diseases from the soil. With this method, it can be tricky to keep your leaves from touching the ground.
The best way to mitigate this is to stake or twine your newly planted tomatoes to help give them some support and keep them upright until they start to grow that way themselves.
Some people also like to do a little training with their tomato starts before planting them with the trench method.
What this means is that they lay their plant on their sides in the days leading up to being transplanted. In an attempt to grow towards the sun, the leaves will turn and begin growing at the sideways angle you want for a trench-planted tomato.
By planting the tomatoes on their sides, you’ve now made it possible for new roots to develop all along this now horizontal stem.
Can you plant grafted tomatoes deep?
Now, there is one exception to these deep planting methods and that is grafted tomato plants. You don’t want to plant your grafted tomatoes too deep and definitely don’t want to plant them horizontally.
What is a grafted tomato?
A grafted tomato plant is made up of the fusion of two different tomato varieties. Oftentimes, the bottom part of one tomato variety is attached to the top part of another variety.
The variety of the bottom half of the graft is usually selected for traits like disease-resistance and drought-resistance and for their stronger root systems as this is part of the plant that gets planted into the ground and is responsible for the uptake of nutrients and water.
The variety of the top part of the plant is selected for traits like high fruit yield and large fruit size. It’s similar to growing a hybrid variety.
Grafted tomato plants tend to be a bit more expensive due to the time and labor-intensive process of creating them. Stems must be precisely cut and fused together by hand to ensure the plant does not die.
Most places that sell plant starts, like garden shops or greenhouses, will carry grafted tomato plants.
If it doesn’t tell you on the tag that the tomato is grafted then take a look at the stem. Grafted tomato plants should all have a small white clip over the grafted area as this is helping to hold the fusion together.
Grafting clips usually fall off on their own but sometimes may need to be removed by hand so that they don’t start to suffocate the plant. But don’t try to remove the clip until they’ve been planted in the ground and seem to be very tight around the stem of your tomato plant.
How to plant grafted tomatoes?
As I mentioned earlier, grafted tomatoes need to be treated a little differently than regular tomato plants. When you go to plant your grafted tomatoes, you do not want to plant any higher than the site of the graft.
To plant your grafted tomatoes, dig a hole that’s deep enough to fit the root ball. This will likely be about 6 inches deep but may be less depending on where your graft is.
If the graft does get buried or is very close to the soil, the top part of the graft will begin to develop its own roots effectively canceling out the benefits of having a grafted plant in the first place.
Other than the graft caveat, grafted tomatoes are planted pretty similarly to how you would plant any other tomato plant.
Make sure no leaves are touching the ground and that the plants are watered in really well without water touching any of the leaves.
Plan to stake, twine, or cage them as they grow to help support their larger size.
So there you have it, planting your tomatoes deeply is simple and gives them a strong advantage in the coming growing season.
You can either plant them using the deep hole method or you can try the trench method and plant them horizontally. Both will help your tomatoes develop deep and strong root systems.
Just remember, if you’re growing grafted tomato plants, then the deep planting methods won’t work for your tomatoes and can do more harm than good.
Make sure to plant these tomatoes no higher than where the graft is or run the risk of it developing roots from the top variety of the graft and canceling out the benefits of the graft altogether.
Tomatoes can seem tricky to grow, but they don’t have to be! Planting them properly will give them a good head start and you’ll get some of the best-looking tomatoes you’ve ever grown before.