Planting Tomatoes Sideways vs. Bury Deeply – What’s the Winning Technique?

How do you plant your tomato seedlings in your veggie garden? “What a question” you may say, but did you know that some gardeners do not put them straight and deep into the soil, but leaning to one side, so sideways? “And why would they ever do that?” Well, according to them it is a better method to transplant them. And maybe they are right, though not always, and noy every way!

If you love a good challenge and enjoy experimenting with innovative (and sometimes “crazy”) gardening methods, let’s dig in and find out together which way of planting tomatoes is best: deeply (straight) or sideways!

The Science Behind Tomato Planting

When it comes to tomatoes, the reason why we can plant deep or on the side actually comes down to undifferentiated stem cell tissue. Essentially, this means there is a bunch of cells in the center of the stem that don’t really know what their job is yet. When exposed to specific conditions, these cells will determine their job.

If you ever notice those little warts on the sides of your tomatoes, those are called root primordia or, in other cases, advantageous roots. These roots, while not necessarily the best at nutrient or water capture, can provide stability and some nutrient and water capture. This is why studies have been done on how exactly to plant tomatoes and why you may or may not want to utilize those stem-type roots in your garden.

What Do We Mean by “Planting Tomatoes Sideways”?

When most people plant tomatoes in their gardens, they dig a hole and they transplant the seedling with the roots down and the tip up, to the sky. But not everybody! You can rest the root ball sideways so that the stalk leans on the ground.

Your tomato seedling will straighten up soon enough, so you won’t get leaning plants as a result, but why would anybody do it? Some gardeners swear by this method, but is it really better than the more traditional and self-intuitive one?

But first of all, wonder how you can plant your tomatoes sideways? Let’s find out!

How to Plant Tomato Seedlings Sideways

We all know how to “deep plant” tomatoes, straight up, but how about sideways? Let’s learn it, so, when we talk about the advantages and disadvantages of this method, you will understand them better. And it is quite simple.

• Dig a shallow hole, only about 4 to 6 inches deep (10 to 12 cm).
• If you want, you can make this hole shallower at one end (where the stalk will rest, while the roots go to the 4 to 6 inches side). But it’s not necessary.
• However, this hole must be longer than usual, about 10 inches (25 cm), in fact, it is not a hole, but a trench.
• Remove all the lower leaves from the seedlings, only leaving the top ones.
• Rest the roots of your seedlings on one side, at the (“deep”) end of the trench.
• Let the stalk rest on its side.
• If there are any leaves left within the trench, remove them.
• Finally, fill the trench with compost or good soil.
• Press gently.
• Water abundantly.
• And I would definitely suggest mulching straight away with the sideways method.

That’s it. Now you have a seedling that comes out from the soil sideways, almost resting on the ground, rather than upwards. It will straighten up, as we said, but why would this be better?

Advantage 1: Sideways Planting Tomatoes Encourages More Root Growth

The first advantage is that if you plant tomato seedlings sideways, they will grow more roots. All the part of the stalk you left underground will develop them, from where you removed the leaves. They will also grow from those bumps you see on the stalk.

True, it is always a good idea to plant tomatoes a bit deep, with 1 to 2 inches (2.5 to 5 cm) of the stalk in the ground, also with the traditional “straight” method, but with the sideways one, more will go underground, so you will get a bigger radical system.

However, these are adventitious roots, and they do get nutrients and water to your tomato plant, but not as much as normal ones for some time. Once they transform into full roots, then they will.

Advantage 3 – Sideways Planting Makes the Best of Top Soil

Most of the nutrients in the soil are in the top 5 to 10 inches (12.5 to 25 cm), what we call topsoil, and shallow, sideways planting means that your tomato will have most of its roots there, encouraging horizontal radical growth, rather than deep.

This gives your seedlings a chance to have lots of nutrients when young, so, again, it helps them establish in your vegetable garden. But this has a flipside too, which we will see in the disadvantages.

Advantage 4 – Planting Tomato Seedlings Sideways Avoids Leggy Plants

Yet another advantage you get from planting tomato seedlings sideways is that you avoid the risk of them getting leggy… Because you bury part of the plant, it will not only focus on developing roots, but also start with a shorter stalk above ground…

On the whole, your tomato will grow sturdier from its early days in the open air in your vegetable garden.

Advantage 5 – Planting Tomato Seedlings Sideways Helps You with Spacing The

This is a small advantage, to be honest, but it also solves a common mistake: spacing the seedlings. Many “green” gardeners transplant tomatoes far too close together, but if you use the sideways method, you must keep them at least 2 feet apart.

Having said this, you can use appropriate spacing when deep planting them as well, 2 to 3 feet apart (60 to 90 cm) and 3 to 4 feet between rows (90 to 120 cm).

But now, on to a last advantage, which can become a disadvantage.

Advantage 6 – Sideways Planting Tomato Seedlings Keeps Their Roots Warm

If the season is warm enough, so, steadily above 55°F (13°C) at night and up to 70°/75°F (21°/24°C), you can transplant your tomato seedlings, and because then top soil is warmer than deeper beneath, their roots will keep warmer.

So, this is an ideal method for colder climates, like the Northern States and Canada, where the sudden drop in temperature is still fairly common even in late spring. On the other hand…

Disadvantage 1 – Sideways Planting Tomato Seedlings May Keep Their Roots TOO Warm

The flipside is that in hot climates, having lots of surface roots means that they may get too much heat, when the Sun beats on the soil, warming up the top layer. In these countries, I think it is better to deep plant your tomato seedlings, so their radical system can keep fresh on sultry days.

Tomatoes thrive to temperatures up to 85°F, or 30°C, but when they are adults. As seedlings, anything above 75°F (24°C), can stress them… It’s a bit too hot for them.

And, linked to this…

Disadvantage 2 – Sideways Planting Is NOT Ideal for Dry Climates

Similarly, if you go through a dry spell, or you forget to water your tomato seedlings, their roots will spread out with sideways planting, and the top layer of your soil may dry up.

For this reason, if you live in a hot and dry region, like Texas or California, I suggest you deep plant your seedlings. Also, later on in the season, when it rarely rains, sideways planted tomato plants may not have developed deep enough roots, and you can see that this will be a problem.

Disadvantage 3 – Sideways Planting Requires Strong and Well- Grown Seedlings

Now, imagine planting a still tender seedling sideways… You run the risk of its stalk rotting underground. Its “skin” (epidermis) is still too thin and tender. It’s not ready to grow adventitious roots, any small hungry bug could have a bite at it, also underground…

So, to plant tomato seedlings sideways, they should already be about 1 foot tall or more (30+ cm), fully hardened, and basically little adults.

The consequence is that you either start the seedlings early (if you have a greenhouse or suitable place) or you can only plant the later…

If you are unsure whether it’s time to plant your tomatoes yet, read our article on when to plant them for a successful season here!

In cold countries, unless you have a warm enough place to grow your seedlings, this can mean delaying your tomato harvest season…

Disadvantage 4 – Sideways Planting Will Put Stress on Your Seedlings’ Stalks

If they have grown up straight as seedlings, and you plant them sideways, they will have to bend and grow upwards again. This is not an easy task for any plant, including tomatoes. You can see that when any vegetable or decorative variety needs to “crook”, it looks stressed, and that’s because they are!

You can get the seedlings to grow sideways already, by tilting the tray or pot, though I would avoid giving them light on one side only, as they may get spindly.

Disadvantage 5 – Your Tomato Seedlings Risk on Frosty Days with Shallow Panting

Again, another twist… Shallow roots get warmer in the day, but also colder at night… Well, it depends on the climate, but frost penetrates the soil from above, so, if the unexpected freezing day happens later in the season (in colder countries, and now with climate change…) your seedling’s roots may get damaged or even die if you plant them sideways, while with deep transplanting, they will be safer…

This is one of the reasons why I strongly suggest mulching them.

So, Which Is Best? Sideways Or Deep Planting Your Tomato Seedlings?

Both methods have their advantages and disadvantages, as we have seen, so, I wouldn’t swear by either of them, as some gardeners do. Maybe sideways planting tomatoes is good in colder climates, and deep planting in warmer places. Similarly, the former may work well later in the season, with seedlings you forgot in your greenhouse and which have grown into little adults already…

So, look at all the advantages and disadvantages, and make your decision based on where you live, how old your seedlings are, and your own circumstances, but… If you have a seedling that’s already grown crooked, well, then, I guess you know which method to use for planting it!