The first time I planted tomatoes on a vegetable farm, I was a bit shocked. Growing up, I always dug a hole just large enough to accommodate the plant’s root ball, then tucked my seedlings into the soil. But these farmers did things a bit differently.
We spent the morning laying out four-inch pots filled with 18-inch tall tomato seedlings, leaving two feet between each plant. Then, we dug holes large enough to accommodate plants three times the size of the ones we were planting. Each hole was a foot deep, even though the root balls were only four inches tall! When we tucked each seedling into their new home, only ten inches of the plant poked out of the ground.
It turns out these farmers were onto something. Planting tomatoes deep in the ground allows them to develop extensive root systems that lead to healthy plants and large harvests. Keep reading to learn more about how deep to plant your tomato plants.
The Short Answer
When it comes time to plant tomatoes in your garden, you want to make sure the root ball is completely covered by soil. That means if your tomato seedling is growing in a four-inch-tall pot, you should dig a four-inch hole, set the seedling inside, and cover the top of the root ball with soil.
While you don’t want to plant your seedlings any shallower than this, I encourage you to plant them deeper! Tomato stems produce roots when they come into contact with soil, so any part of the stem you bury will produce new roots. A good rule is to bury half of your tomato plant underground while leaving the other half exposed. For example, bury a 12-inch tall plant six inches under the soil surface.
The Long Answer
Since tomato plants are frost-sensitive crops with a long growing season, people often start the seeds indoors and transplant the seedlings outdoors a few months later. While many people know the importance of proper transplanting time, fewer know their ideal planting depth. While there isn’t one best planting depth for all tomato plants, planting some of the stem underground leads to healthier plants and larger harvests.
Comparing Tomatoes to Other Vegetables
Planting seedlings at the soil level prevents rot and promotes growth.
When you think about planting lettuce, kale, or peppers, you probably imagine digging a hole the size of the plant’s root ball, tucking the seedling into the ground, and covering the exposed top of the root ball with a dusting of soil. When you step back, the seedling looks the same as it did in the pot, but it’s just in a new home. There are two main reasons why planting seedlings in line with the soil surface works well for many crops.
First, keeping the plant’s leaves and stems above ground prevents them from rotting. If you’ve ever planted a cucumber seedling too deep, you know how quickly a previously healthy seedling can turn to mush. This planting depth also ensures that low-lying growth points remain above the soil surface and continue to grow.
With all this said, tomatoes are a bit different. Their stems are hardy, so they won’t rot when placed under the soil. Instead, they’ll grow more roots! And since tomato plants grow from the apical meristem present at the top of the plant, you don’t have to worry about staling plant growth by burying the bottom of the stem under the soil surface.
Deeper Plants Equal Stronger Roots
Planting tomatoes deep promotes robust root systems for healthier plants.
Now that you know tomato plants can survive being planted deeper than many other veggies, let’s explore why you’d want to plant your tomatoes deep in the ground. After all, just because you can do something it doesn’t mean you should!
When it comes to tomato transplanting depth, it’s all about the roots. When tomato stems come in contact with soil, they develop roots. That’s why you see poorly trellised tomato stems rooting into the soil. You can use this feature to help your tomato plants develop robust root systems.
Plants with larger root systems have an easier time taking up water and nutrients. Robust root systems also help tomatoes withstand drought, as they can reach water deep in the ground or a few feet away from the base of the plant. When tomatoes have access to the water and nutrients they need, they are better able to fight disease, complete photosynthesis, and produce new leaves and fruit. In short, they’re healthier.
Will Planting Tomatoes Deeper Stunt Their Growth?
Deeply planted tomato seedlings may seem shorter initially, but will result in stronger growth.
Many people are worried that planting tomatoes deep in the ground will result in smaller plants and minuscule harvests. And this is a reasonable thought! I admit it’s a bit concerning to watch the ground swallow up a previously 18-inch tall tomato seedling until it’s half its original size. But the truth is that the tomato isn’t stunted; it’s only disappeared so it can grow stronger.
In the first few weeks after planting, deeply planted seedlings often remain shorter than those you tucked just a few inches under the ground. But after a few weeks, the root systems on the deeply planted seedlings allow them to catch up to and overtake their shallow counterparts.
Tips for Planting Tomatoes Deep in the Ground
Use a full-size shovel for easy digging.
Even if you know you should plant your tomatoes deeply, it can be difficult to do so. If you’re in a rush, transplanting dozens of tomatoes, or dealing with compacted soil, it’s a lot easier to dig a six-inch hole than an 18-inch hole. Fortunately, there are some tips and tricks for making digging deep holes easier.
First, grab a shovel. Trowels are great for small holes, but full-size shovels make digging deep holes much easier. Not only does their deep blade make it easier to remove lots of soil at once, but steeping on the blade with your foot is an efficient and easy-on-the-body way to break through compacted soil.
If you’re planting lots of tomato seedlings, another option is to use a hand-held auger. Many small-scale farmers use a drill-powered auger bit to quickly dig uniform, deep holes.
Remove Leaves at or Below the Soil Surface
Trim or pinch off lower leaves before planting tomatoes.
Before you plant your tomato seedlings in the ground. When buried, these leaves won’t be able to complete photosynthesis and will be susceptible to rot. A sharp and sanitized pair of pruning shears makes it easy to trim the leaves where they connect to the stem, but you can also pinch off small leaves with your fingers.
You should also remove any leaves that will come into contact with the ground once your seedlings are planted. Leaves that touch the soil are susceptible to developing soil-bourne diseases like verticillium wilt and fusarium wilt.
Can You Bury a Tomato Plant Too Deep?
Plant tomatoes deeply, but avoid burying the top growth.
Yes, you can plant a tomato plant too deep! While deep planting encourages the plant to produce a healthy root system, it can also lead to issues with plant health and growth.
Since tomato plants produce new growth from the top of the plant, it’s essential to leave this portion of the plant above the ground. You should never bury the top two to three inches of your plant. I recommend leaving at least one set of true leaves above the ground to ensure that the plant has adequate tissue to photosynthesize.
Final Thoughts
When it comes to planting tomatoes, remember that deeper planting equals healthy plants! Burying half of the stem underground will allow the plant to develop a strong root system while leaving enough foliage above ground for continued photosynthesis and growth.
