It is basically gardening 101 to plant your tomatoes deep, burying some of the stem under the soil. This is said to have many benefits, from quicker root establishment, to higher yield, and a sturdier plant.
Another similar method involves planting tomatoes sideways. The outcome is similar, but both techniques can lead to a better result from your tomato plants.
In this article, we’ll explore both of these methods; planting deeply and “trenching” tomatoes. I’ll also cover why using these methods might just be the best way of planting tomatoes if you want the best possible yield. Let’s get started!
Planting Tomatoes Deep
Since the dawn of home gardening, there have been word-of-mouth “secrets” to a healthier, more productive garden. I can’t exactly pinpoint when the notion of planting tomatoes deep started, but today, it is basically a rule of thumb.
Essentially the idea is to dig a hole that is deeper than the root ball, burying the tomato stem up to the first true leaf. Compare this to planting a tree, where it is only advised to plant at the same depth of the root ball.
Thankfully, there is scientific evidence to support the deep planting method. In a Florida study, planting tomatoes deep was shown to increase yield, size, and lead to an earlier maturity date.
There are more benefits to planting tomatoes deep. For example, the extra depth provides physical support to young, delicate tomato stems. This can help avoid broken stems from wind damage early in the season.
In warmer climates, the extra depth regulates the soil temperature at the root ball, potentially helping the plant establish better. This may not be a benefit in cold climates during the early spring.
The method seems logical, and I do personally recommend planting tomatoes deeply for the reasons above. If you have your doubts, try a simple experiment to see which works better for you.
Read Next: Summer Tomato Growing Tips
How Does It Work?
The reason that planting deeply is even possible is thanks to adventitious roots. Essentially, when a tomato stem is exposed to certain conditions, it will begin to form roots directly from the stem tissue.
I often get questions like, “What are those white, nubby bumps on my tomato plant’s stem?” Those are adventitious roots, often caused by humid air or stuffy conditions around that part of the stem.
When planting deep or sideways, we are encouraging the buried portion of the stem to produce these new roots underneath the soil. The moist conditions quickly initiate their production, and the plant begins growing more roots.
How Deep To Plant Tomatoes
The perfect depth is not known for sure, but we have a good idea of where to start. It is best to plant tomatoes deep, well above the root ball, and as high as the first true leaf. Some prefer to go deeper, while others stay as shallow as the cotyledon leaves.
Follow these easy steps to plant tomatoes deep:
- Dig a hole that is as deep as the first true leaf. Measure from the bottom of the root ball up to the first true leaf. This should be the approximate depth of the hole.
- Remove the first true leaf. Cut off the first true leaf, along with the cotyledons. I prefer to do this 1-2 days prior to planting to give the wounds time to heal.
- Place the root ball into the hole and bury it. Simply plant your tomato in the deep hole, burying it to the soil’s surface.
- Water deeply. Since the roots are deep below surface, be sure to irrigate heavily, right after planting.
Note: To avoid possible confusion, do not plant tomato seeds deep. When planting tomato seeds, they should only be about 1/8″ below the surface.
What About Planting Tomatoes Sideways?
Planting deep is a great option, but there are a few scenarios where planting sideways might be a better choice for you. Also called “trenching,” this method involves laying your tomato seedling on its side and burying some of the stem.
Why Plant Tomatoes Sideways?
There are several reasons to try planting your tomatoes sideways instead of deep. Some are physical, while others are climate related.
- Plants are leggy. If your plants are tall, leggy, and have lots of space between leaves, sideways planting may be better than deep planting.
- Soil is hard to dig. If your soil is compacted, or is otherwise difficult to dig, it might be easier for you to dig a more shallow trench than a deep hole.
- Deep soil is too cold. If you live in a northern climate, the deep soil can be cold in the early spring. A shallower hole may have a more suitable temperature for tomato roots.
The effect of planting sideways is essentially the same as planting deeply. It stimulates new root growth along the buried stem, and helps support the above ground stem.
How To Plant Tomatoes Sideways
Unlike a deep planting, sideways “trenching” requires a couple days of preparation. It is easy, but definitely recommended to take these simple steps before planting tomatoes sideways.
- Lay the plant on its side 2-3 days before planting. To train your tomato plant to grow upwards, lay it on its side a few days before transplanting. You will quickly notice that the upper part of the main stem will start to curve upwards. This step is crucial to avoid bending the stem, potentially damaging it.
- Remove leaves from the lower stem. At the same time your lay the plant sideways, remove the lower leaves. I don’t recommend burying the leaves, just the stem. Try to keep the junction between the leaf and the stem unharmed.
- Dig a trench. After your plant has begun to curve upwards, dig a long trench approximately the length of the horizontal portion of the plant. The depth of the trench should be about the diameter of the root ball.
- Place the root ball and stem in the trench. Lay the plant into the trench, allowing the stem’s curved tip to be above ground.
- Bury the stem and root ball. Back fill the trench with soil, and compress lightly.
- Water deeply. Be sure to water the entire trench area to saturate the root ball and the buried stem.
It is important to remember where the root ball and buried stem are located so that you can irrigate properly. Try marking the spot where the root ball was positioned at the time of planting.
What If I Grow Tomatoes in Containers?
Growing in containers makes the deep planting method easy. I do recommend planting deeply when growing tomatoes in pots, however, trenching is not ideal since containers are often too narrow.
Instead of digging a hole, you can simply fill the pot halfway with soil. Then, add the plant to the soil at the proper depth (up to the first true leaf), and surround the stem and roots with soil.
If you haven’t tried planting your tomatoes deep, I recommend you give it a shot. There are so many possible benefits, and very little in the way of drawbacks. What do you have to lose?
To summarize the benefits:
- Planting deep or sideways can increase tomato productivity, fruit size, and improve time to harvest
- Warm climates should plant deep rather than sideways when possible to benefit from cooler soil temperatures
- Colder climates may wish to try trenching, or planting sideways, instead of deep to avoid soil that is too cold
- Planting tomatoes deep helps physically support the stems, reducing breaks early in the season
Whether it improves your plant’s performance or not, there are clear benefits to planting deep in virtually all growing scenarios. Let me know how you like to plant your tomatoes in the spring below. Happy growing! 🍅