How to Transplant Your Tomatoes in 7 Easy Steps
Looking to transplant tomatoes in your garden but aren't quite sure where to start? Transplanting tomatoes propely can require some finesse, especially for new gardeners. In this article, gardening expert and homesteader Merideth Corhs walks through how to transplant tomatoes in your garden by following 7 simple steps!
Putting plants into the ground is probably one of the things I enjoy most about spring and early summer. I grow my tomatoes from seed so it’s somewhat of a relief to get the plethora of young seedlings out of my house and into the dirt!
Knowing how to correctly transplant your tomatoes will set your plant up for success and a bountiful harvest. Transplanting is so much more than digging a hole, plopping your plant inside, and hoping for the best.
Here are the 7 steps I use for transplanting my tomatoes each year. After a lot of years of trial and error, I have found these to be the most important actions and considerations you can take. But before we dive into those steps, first things first…
Timing is Everything
Every single year in my local gardening groups, I see people who eagerly plant their tomatoes when temperatures start to warm up. Invariably, after a week or two of temperatures in the 70s or low 80s, we have 3 weeks of temperatures in the 50s with heavy winds. The gardeners who were so full of joy are now a ball of stress as they see their young plants struggling in suboptimal conditions.
So although the general rule of thumb for planting warm season crops like tomatoes is to plant once you’re 2 weeks past your final frost date, there are some nuances to consider.
Tomatoes like to be outside once soil temperatures have warmed to 55-60 degrees. This usually happens when nighttime temperatures don’t fall below 60 and daytime temperatures are well into the upper 70s.
In my area, Mother’s Day is a key milestone for planting tomatoes outside even though we’re technically far past our frost date. If you’re not sure when to plant outside, I encourage you to join local gardening groups and ask! Gardeners are generally a friendly lot and are eager to share their wisdom, especially when it can save you from a lot of heartache.
Remember, young healthy transplants yield greater abundance compared to older, stressed transplants every time.
Transplanting Tomatoes in 7 Steps
Whether you have grown your tomatoes from seed or have purchased starts from your local nursery, these steps will ensure your young tomato plants survive transplanting and grow into beautiful productive plants!
Step 1: Harden Off Your Plants
Up until now, your tomato seedlings have lived in a very sheltered environment. Perfect indoor or greenhouse temperatures, ideal light exposure, and only the most gentle of breezes. This is a far cry from what your plants will experience outside. This is where hardening off comes into play.
Hardening off is a simple, but necessary process that allows your tomato seedlings to acclimatize to heat, wind, and sun. During this period, your young tomatoes will ‘grow up’ a bit. Their stems will thicken, leaves will reach out strongly, and roots grow more quickly. All of this helps the plant deal with temperature changes, strong gusts of wind, and direct sun without any problems.
The hardening off process should take a week or two. The longer you give your tomatoes to adjust, the healthier and stronger they’ll be when you finally plant outside.
Start by setting your tomato seedlings in a protected shady area for about an hour. The next day, put them in the same location, but for 2 hours. The day after that, you can let them experience a little bit of gentle morning sun. Gradually increase sun exposure and time outside each day. The idea is to introduce new things in manageable chunks that allow the plant to adjust in small ways each day.
A note on wind. It’s important to protect your young tomatoes from wind in the first week of hardening off. Too much wind too early will cause dramatic leaf curling. This can cause issues with growth since the leaves are not absorbing as much sun as they should.
After the first week outside, allow them to experience normal gentle wind currents, but move them immediately if you experience extreme wind gusts.
Step 2: Choose the Right Location
Where you ultimately plant your tomatoes makes a big impact on their health, vigor, and fruit production. Tomatoes are a little fussy when it comes to things like sun exposure, soil conditions, and room to grow. Before you think about transplanting your tomatoes this season, take the time to find the location where they will truly thrive.
The amount of fruit your tomatoes produce has a direct correlation with the amount of sun they receive. Each year I plant two cherry tomato plants in large containers on my deck. One plant gets maybe 20 minutes more sunlight than the other and the difference in production is HUGE!
Tomatoes need to be planted in an area that receives full sun, meaning at least 6 hours of direct sun each day. Ideally, they’d like 8-10 hours of sun for maximum fruit production. If you’re not sure how much sun your space receives, take a few days to actively measure it. Note when the sun first reaches a particular area, if it’s ever shaded by tall trees or other buildings, and when it leaves for the day.
While your tomatoes will be fine with western or eastern exposure, southern exposure is really the gold standard. Southern exposure provides yoru tomatoes with gentle morning and early afternoon sun while protecting the plant from the harshest afternoon rays.
Tomatoes are heavy feeders and require organically rich, fertile, well-draining soil to thrive. If you are planting your tomatoes in raised beds or containers, fill them with a rich, loamy, well-draining outdoor potting soil.
About a month prior to planting, amend that soil with compost and gently dig it in. Amending your soil in this way will ensure your young tomato plants have all the nutrients they need to grow and ensure the soil is light and well aerated (this will prevent soil compaction).
If you’re planting directly in the ground, your amendments will depend on what type of soil you have. Sandy soil requires an abundance of organic material like compost, while clay soil needs help with drainage (coconut coir is an excellent choice for this since it improves airflow even when wet, and lightens clay).
Tomatoes also prefer soil that is slightly acidic – ideally with a pH between 5.5 and 7.5. It’s a good idea to test your soil before planting to see where things are. If you find your soil is too alkaline, add a soil acidifier at the same time as your compost.
Tomatoes really like their space. Although your seedling is small and adorable now, it will quickly grow into a large sprawling plant in no time.
Well spaced tomato plants will reward you with healthy, disease free foliage and delicious tomatoes. If you plant them too closely together, they can be more vulnerable to pests and disease.
Airflow is also really important to the overall health of your tomatoes. Densely planted tomatoes have an obvious problem with air circulation, which can lead to conditions that attract pests and disease.
As we talked about above in the soil section, we know that tomatoes are incredibly nutrient hungry (this is why you need to fertilize them consistently throughout the growing season). Too many tomato plants in a small area will create conditions where the plants are competing for limited resources. This can cause nutrient imbalances, stunted growth, and poor fruit production.
Lastly, your tomatoes need lots of sun! If they’re planted too closely together, some plants may actually wind up in partial shade conditions, which will impact growth, flower development, and fruit yield.
A good rule of thumb is to leave 30-46” between each seedling when transplanting outside.
Step 3: Gently Prune Your Seedlings
Just prior to transplanting your tomato seedlings, take a few minutes to gently prune and clean up the plant. I always trim off at least one set of leaves to allow me to bury the plant a little deeper in the ground. If your seedlings are a bit on the tall side, feel free to trim off 1-3 sets of leaves as long as you leave 2-3 sets intact above the soil line.
Although it goes against all your basic instincts, this is also a time to pinch off any flowers that may have formed on your young seedling. At this stage, your plant needs to put all its energy into overall growth, root expansion, and foliage generation. Your tomatoes will start to flower again in no time.
Step 4: Dig a Hole and Bury the Stem
You’ve done all the prep work to harden off your plants, prepared the ideal location, and amended the soil. It’s time to put your tomato seedlings in their final home!
Start by digging a hole about twice as large as the pot your tomatoes are currently in. Your starts are likely in flexible nursery pots at this stage, which makes transplanting pretty easy. Gently squeeze the sides of the pot to loosen the soil.
Tilt the pot sideways, gently grip the base of the stem and slide it out. You shouldn’t feel any resistance here; the plant should slide out quite easily. If you do feel resistance, stop. Try watering the soil to moisten it more and try again.
Some people grow tomato seedlings in biodegradable pots like CowPots. If you’ve done that, transplanting is a breeze. Just trim off any part of the pot above the soil line and you’re ready to go.
If you added good compost to your soil as we discussed earlier, you can probably skip this part. Good compost should provide your young plant the nutrients it needs to start its growth spurt. If you skipped that step, now is the time to add fertilizer.
Tomato fertilizer adds a particular balance of macronutrients like nitrogen, phosphorus, and potassium, and micronutrients like magnesium, calcium,and zinc.
Here’s a little cheat sheet on the macros you find in fertilizer:
Promotes foliage growth. Too much will lead to very bushy plants with little to no fruit.
Crucial for the growth and development of roots as well as fruit. Very important in both the initial stage of growth as well as the final stage of fruiting.
Helps the plant grow rapidly and produce flowers and fruit. Also important to efficient photosynthesis and tolerance for some diseases.
When transplanting, a balanced (10-10-10) slow release fertilizer is the ideal choice. As your young plant grows and starts to flower, a fertilizer higher in phosphorus and potassium (5-10-10) is recommended. This will help the plant produce more flowers and direct its energy into turning those flowers into fruit.
Tomatoes are pretty unique in the vegetable world because they can grow roots from any part of their stem that is buried underground. Transplanting is a really excellent opportunity to help a seedling that may look a bit tall or ‘scraggly’ grow into a healthy plant with a strong root system.
Since we already trimmed off the bottom sets of leaves, we can bury the plant much deeper than we could have had we not done this. Aim to bury half to ⅔ of the tomato stem into the ground. Your plant will look really small after all is said and done, but it will be much stronger and healthier as a result.
Once your tomato plant is as deep as you want it, cover the root ball with soil and gently press down with your fingers. It can be helpful to slightly mound the soil around the seedling to help with water runoff.
Step 5: Start Mulching
Mulching is an often underrated element in gardening. I freely admit that it never occurred to me that I should mulch my garden in my early years. But, I have since learned that mulch is incredibly important to the health of your tomatoes.
Mulch helps keep the soil cool during excessive heat, helps the soil retain moisture (there won’t be as much evaporation on the surface during hot days), prevents water splash back (which can spread fungal disease), and discourages weeds.
You can use a lot of organic materials as mulch. Straw, grass clippings, wood chips, eggshells, and crushed up leaves are all things you can repurpose from your yard (if it hasn’t been treated with herbicide/pesticide). You can also use mulch purchased from your local nursery or garden center. Personally, I love to use coconut coir as mulch. You can purchase mulch blocks that just need a soak in water prior to use.
Aim to apply a layer 2-3” thick for maximum benefit. When you first transplant, this might seem like a lot of mulch in relation to the size of your plant. But as your plant grows, it will look better!
Step 6: Water Generously
Young seedlings need a lot of water in the beginning stages of their lives since their root system is still quite undeveloped. Properly watering your tomatoes at the time of transplant is one of your best tools to ensure your plant grows healthy and strong. Aim to water slowly and deeply once a day for the first two weeks. Unless you get a really good soaking rain overnight, plan to water each morning.
Check out this article on how to water your tomatoes for a full rundown of how often and how much to water your plants as they grow.
Step 7: Support Your Plants
You may not know this, but tomato plants will grow happily along the ground if you let them. Unfortunately, this can invite fungal diseases, give pests and rodents easy access to the fruit, and doesn’t encourage the plant to maximize fruit yield. So, gardeners have long trained their tomato plants to grow vertically by staking or caging.
Even though your tomato plants are quite small at the time of transplant, it’s a good idea to install both stakes and cages when you first put them in the ground. This ensures that you don’t disrupt the root structure or break any branches by installing them after the plant has grown.
There are a number of different tomato cages and stakes you can choose from and a lot will depend on the variety of tomato you have chosen to plant. Large indeterminate tomatoes will need a different level of support than bushing determinate varieties.
I tend to use both cages and stakes with all of my tomatoes, but this can be personal preference. If you do use stakes, plan to attach the tomato stem to the stake with a loose tie (nothing that will cut into the stem) above the first set of leaves.
Ensure this tie is nice and loose so that the growing stem doesn’t become restricted. The first tie at the time of transplant is really to help the young plant withstand too much wind.
Frequently Asked Questions
Can You Transplant Seedlings with Flowers?
Technically you can, but I highly recommend pinching off any flowers prior to planting in the ground. It may go against your instincts (early flowers mean early tomatoes!), but if a young plant is putting its energy into creating flowers and fruit, it’s not putting energy into growth. In fact, if it’s flowering at a young age, it’s already feeling stress and trying to produce new tomato plants.
Letting a tomato plant flower at this stage will stunt its growth and certainly limit the plant’s overall yield. So while it may be tempting to let those flowers bloom, help your tomatoes focus on growth – foliage and branch development – so you have more tomatoes than you know what to do with later in the season!
How Big Should The Plants Get Before Transplanting?
Your tomato plant should be about 3 times the height of its container when you transplant outside This will ensure roots have filled out the current space and there is enough stem to bury underground.
Why Should I Bury Half of My Tomato Plant?
Burying your tomato plants deeply into the soil helps them grow better and develop strong root systems. Most vegetable stems would simply roth with that much exposure to soil, but tomatoes have evolved to sprout roots instead. Planting your tomatoes deeply will help especially if you have tall, leggy seedlings.
How Many Times Can I Transplant Tomatoes?
A tomato plant can be repotted or transplanted 2-3 times prior to being planted outside in your garden. I grow my tomatoes from seed and typically transplant them twice prior to planting (although I have done it 3 times before when I started my seeds too early in the year). Each time you transplant, you have the opportunity to help your plant become healthier and develop a strong root system. Bury the stem each time and you won’t ever deal with leggy seedlings.
How Do I Transplant My Tomatoes Into a Pot?
Transplanting your tomatoes into a pot or container will look almost exactly the same as transplanting them into the ground or a raised bed. Really, the only difference is that you have the opportunity to move your pot into an area that receives the perfect amount of sun exposure!
For maximum fruit production, choose a pot that has at least an 18” diameter for determinate tomatoes and at least a 24” diameter for indeterminate tomatoes.
Now that your tomato plants are in the ground, it’s time to dig into the joys of gardening. Your tomatoes may be in their final home, but they still need a lot of attention from you. Focus on proper watering habits, look out for issues with pests and disease, and get ready to harvest your fruit early and often. Happy planting!