How to Grow Tomatoes From Seed in 7 Simple Steps

Growing tomatoes from seed can be more of a challenge than if you buy starts from a local nursery or farm. It takes a bit longer, and quite a bit can go wrong if you do things incorrectly. In this article, gardening expert and homesteader Merideth Corhs walks through each step you'll need to follow in order to successfully grow tomatoes from seed.

Growing Tomatos From Seed

Growing tomatoes is a must in my garden each year. I can somehow never seem to grow enough tomatoes – beefsteak, saucing, cherry, heirlooms – I want them all! Romas are my tried and true variety for making pasta sauce (I make and freeze enough in the summer to last a good chunk of the winter months), but I’ve also had great success with San Marzanos.

I always have at least 1-2 sprawling cherry tomato plants because I love that sweet, bursting bite in salads, on toast, and in eggs. And every year, even though I don’t think I have the room, I always find an extra pot or two for heirloom varieties. The colors, shapes, and flavors of those just can’t be beat. I love eating thick slices with a little salt and pepper and an accompaniment of fresh mozzarella.

The point is that tomatoes are iconic. And a whole new world will open up to you once you decide to grow tomatoes from seed. No longer are you at the whim of your local garden center. Instead, you can dream of exactly the type of tomato you want to eat, find seeds, and grow!

Picking The Right Tomato Type

Kinds of Tomatoes
Choose the varieties that you grow based on how you most enjoy your tomatoes.

Choosing the right tomato variety is all about identifying how you like to eat them. You can grow beefsteak varieties for slicing and sandwiches, saucing varieties like Romas and San Marzanos, or sweet cherry tomatoes that you pop off the vine right into your mouth! And with the prevalence of online seed retailers, the sky really is the limit.

Seed catalogs really opened up the world of seed starting. They contain a huge selection of tomato varieties including cherry, grape, plum, cocktail, beefsteak, paste, and heirlooms. You can find indeterminate or determinate varieties of each of those, and opt for fruits that range in colors from red, green, yellow, orange, purple, to striped!

The bottom line is that you should take a moment at the beginning to decide what you really want to grow. As I previously mentioned, my garden focuses on Romas (determinate), cherries (indeterminate), and a selection of heirlooms.

Burpee, Baker, and TomatoFest are great places to start looking at seeds, but there are a lot of options out there. Be sure to read reviews, and see how other gardeners have fared with the varieties you’re interested in.

What You’ll Need: Equipment List

Materials Needed
Make sure you have the materials and tools you need before you begin.

Growing tomatoes from seed is an incredibly fun and fairly easy process. It does require some equipment though. Let’s take a look at everything you need – from the must haves to the nice-to-haves – to grow your tomatoes from seed this year.

Equipment and Tools

  • Trowel. You will need a gardening trowel for filling small pots with soil and transplanting your seedlings outside when they’re ready. I like one that has a sharp point to it (we have lots of rocks in clay soil where I live), but any kind will do the job.
  • Gardening Gloves. Gloves are, of course, optional. But I strongly recommend them especially for extended time with your hands in the dirt. You’ll save yourself a lot of cleanup time, and there are very few things more annoying than trying to remove caked dirt from under your nails (male or female).
  • Seed Starter Trays. We’ll get into this in more detail below, but you will need some kind of seed starter tray for your seeds. This can range from plastic trays designed for this purpose, biodegradable pots, or homemade versions.
  • 3-4 Inch Transfer Pots. Once your seedlings have begun to grow, you’ll want to move them into a pot with more soil to encourage continued root system growth. There are a number of options for this, but you’ll want something that is made of flexible material to make later transplanting easier.
  • Plant Markers. If you grow more than a few plants, you’ll need a way to keep track of them! You can use something as simple as popsicle sticks to make colorful plastic markers that you can reuse each season.
  • Grow Lights (optional). Grow lights make seed starting incredibly easy. You have a one-time upfront purchase, but they can be used for many years to come. If you don’t have or don’t want to add grow lights to your system, you’ll need a very well-lit window or outdoor greenhouse. Seedlings can need 12-16 hours of light a day, so this is an important step.
  • Heating Mat (optional). Heating mats are 100% optional, but they make germination an absolute breeze. Outside of seed starting, I use my heating mats to help with bread dough rising. They’re a heavy use item in our house!
  • Fan (optional). Fans are a great addition to your indoor seed starting system. Young seedlings need to learn how to cope with outdoor conditions, and a light breeze from a fan does the job well.

Materials

  • Seeds. Once you decide what kind of tomatoes you want to grow, you’ll have to buy seeds! You can get seeds from a host of places including your local nursery, garden centers, or online retailers.
  • Potting Mix. I have seen people use all kinds of soil for seed starting. You can certainly use whatever you’d like, but for best results, choose a sterile seed starting mix. These mixes are designed especially to help with germination and quick seedling growth, and do not have any soil contaminants that could affect your plant.
  • Water. You’ll be watering your seedlings regularly, so have a source of water close by.
  • Liquid Fertilizer (optional). Personally, I don’t use fertilizers on my young seedlings, but this is largely because the seed starting mix I use comes with the right mix of nutrients already. If you’re using a generic potting mix, you may want to consider this.

Growing Tomatoes From Seed

Time to Grow
Growing from seed does take some work, but having juicy, delicious homegrown tomatoes is worth the effort!

Now that we know what we need to get started, let’s dive right in! This section is set up by steps so you can logically see everything you need to do to successfully start tomato seeds this season.

We’ll talk about choosing the right seeds, preparing your seed starter system, planting seeds, caring for growing seedlings, hardening off your young plants, and finally planting them outside.

Step 1 – Choose Your Seeds

Select Seeds
Be sure to read reviews before selecting your seeds.

We touched on this earlier, but choosing the right seeds is a critical step that you don’t want to rush through. I get a number of seed catalogs each spring and I always feel like a kid in a candy store when they arrive. You’re presented with pages and pages of the most beautiful produce photos and you want to plant them all!

The first choice you have is the general type of tomato you want to eat this season. If this is your first year growing tomatoes, I recommend starting with a single variety (or maybe two if you just can’t help yourself). Having only a single kind of tomato plant will enable you to simplify the growing process and keep things as uncomplicated as possible.

Once you’ve decided what variety you want and have found the seed retailer of your preference, it’s time to choose the actual seeds! In your first season, I highly recommend going with a variety that is well reviewed.

Gardeners are really great about sharing their wins and their frustrations. If you see glowing reviews for a certain tomato plant, give it a try! Conversely, if there are a lot of reviews talking about poor germination rates, look elsewhere.

Some Top Choices

If you’re feeling a little overwhelmed by the sheer amount of tomato options, take a look at some of my favorites. I have grown a lot of varieties over the years, but these are all tried and true producers that provide incredibly flavorful (and pretty!) fruits.

Rosella Cherry Tomato
Rosella
This variety is great for eating right off the vine.

I have tried a number of cherry tomato plants over the years and this one is definitely at the top of my favorites list. The plant produces massive trusses of pink to purple cherry tomatoes.

They’re pretty tiny (which is what I like!) – only ½” across – contain very few seeds, and are perfect for fresh eating. Interestingly, because they are so dense, they actually do really well in sauces too. Sometimes I have way too many cherries at one time, so I’ll throw a bunch in a batch of pasta sauce!

Roma Tomato
Roma
This is a great variety for making pasta sauce!

This is my standby tomato for sauce-making. There are a number of kinds of Romas you can find, but I always stick with the heirloom variety. Since I use these for saucing, I prefer a determinate plant that is going to set the majority of its fruit at once.

San Marzano Tomato
San Marzano
Use this variety to make a flavorful sauce.

I often compliment my Romas with San Marzanos. They’re not quite as easy to grow, but the flavor of the tomatoes just can’t be beat. If you’ve bought canned San Marzanos at the store, you know what I’m talking about! If I run out of my own sauce during the winter, I always turn to the canned variety of this tomato to make marinara or chili.

Cherokee Purple Beefsteak
Cherokee
Enjoy the sweet flavor of these heirlooms fresh with a little sea salt and balsamic.

This has to be the coolest heirloom beefsteak I’ve grown. I tend to get a lot of cool tomatoes from our CSA, so I typically limit my own planting to 1-2 heirloom varieties.

This one is almost always on my list! An old Cherokee heirloom from before 1890, this tomato has a deep, dusky purple-pink color, has an incredibly sweet flavor, and produces very large fruit. It definitely seems to be a popular choice according to many online retailers!

Pro Tip

Look for organic, non-GMO seeds whenever possible. This isn’t necessary of course, but if you want to consider using the seeds from your plants next year, it’s a must. If you are at all eco-friendly, this is also pretty important.

Conventional seed production is one of the most chemically intensive types of agriculture. Since seed crops don’t fall into the food category, pesticide regulations are much more lax than they are with vegetable crops. Every time we purchase seeds through those conventional producers, we’re reinforcing the practice.

If your area is prone to certain diseases (or you have had trouble with certain diseases in the past), choose a hardy tomato variety. Some heirlooms have natural resistance, while others are bred to overcome them.

If you want all your tomatoes at once (for preserving or making sauce), choose a determinate variety. Indeterminate varieties will continue to bear fruit and grow all season.

Step 2 – Seed Starting Preparation

Prepare Starting System
Use one of the systems mapped out below, or mix and match to find what works best for you.

Before you can plant your seeds, you have to choose what type of seed starter system you’re going to use. And I do mean system… Seed starting is incredibly rewarding, but it does require some ‘stuff’ to make it work. Here are some questions you may want to ask yourself prior to getting started:

Questions To Ask

  • Do I want to start seeds for a small number of plants?
  • Do I want to start seeds for an entire vegetable garden?
  • Am I ‘kicking the tires’ on seed starting?
  • Or, do I know that I’m going to do this year after year?
  • Do I want to look at DIY options?
  • Do I want to invest some money in a done-for-me system?

Choosing how many plants you want to start will be your main consideration for choosing a way forward. Options range from a minimal DIY approach, seasonal indoor systems that you put away after planting, and permanent indoor solutions that are more like furniture.

If you’re planning to start only a few tomatoes this year, you’re probably better off with a DIY approach. But if your goal is to start a large number of tomatoes – or even an entire vegetable garden – from seed, you may need a more robust solution.

Let’s break it down into the done-for-you option that will require some upfront investment, followed by the DIY solution you can do with items already found in your home.

Both solutions will allow you to start tomato seeds this year, so it’s 100% about personal preference. The bottom line is that starting your plants from seed is really fun, so choose the option that gets you excited to plant!

Done-For-You Solution

Done For You Growing System
This system is a great option for long-term seed starting for your garden.

When I decided to start my own seeds, I knew I wanted an easy system that I could set up once and then roll with it again year after year. My goal was to grow enough vegetables in my home garden to replace what I purchased at the grocery store.

This required a fairly robust system that gave me enough room under my grow lights to accommodate both young seedlings and recently transplanted starts. I opted for the system I’ll outline here.

Lighting: Multi-Tier Grow Lights

I opted for a stackable grow light system that would allow me to add levels as I needed them. I started with a 2-tier system and have since grown it to 4. Stacking systems allow you to get what you need for the current season, and add more when you’re ready.

They are easily collapsible for off-season storage and are usually made with lightweight materials (think PVC or plastic). You can get really nice, decorative ones as well if you’re looking to keep grow lights going all year long. Check out Gardeners Supply Company or similar online retailers that specialize in grow kits.

If you’re going to purchase a system, look for one with adjustable grow lights. This will allow you to move the lights up or down depending on the height of your seedlings. Some systems will also come with an extender system for larger plants like tomatoes. I found this feature invaluable since I have to keep my tomatoes indoors until May in northern VA. If you live in a hotter climate, you will need to adjust your tomato strategy to grow earlier in the season.

Seed Starter Trays

My preference for seed trays are reusable plastic self-watering trays. I’m kind of a ‘lazy’ gardener and these solve the challenge of over- or under-watering my seedlings. All you do is fill the reservoir with water and the tray does the heavy lifting. Look for a tray that comes with a plastic dome. This is essential for seed germination where a ‘greenhouse’ environment is needed.

If you don’t like the idea of reusable plastic trays, you can look at biodegradable trays instead. My favorite are CowPots, which are made from composted cow manure sourced from a Vermont dairy farm.

They’re eco-friendly since they reuse waste material, and once you plant them, they’ll provide nutrients to your plants as they break down. You can buy these from any garden center or online retailer. We’ll talk about a few of the DIY seed starter options – eggshells, toilet paper rolls, etc – in the section below.

No matter what kind of seed tray you choose, make sure that it’s well draining. If your tomato’s roots stay too wet, they will be more susceptible to diseases like ‘damping off’.

Seed Starting Mix

I highly recommend a sterile seed starting mix. Regular garden soil that hasn’t been sterilized can negatively impact the health of your young tomato plants by introducing harmful diseases or even seeds from other plants.

You can find sterilized potting soils, but they can be too heavy and dense for young seedlings. Seed starting mixes are very light and are designed for strong root development.

I really like the seed starting mix from Gardeners Supply, but I have also had great luck with pure coconut coir. This is an eco-friendly replacement for peat moss that gives your tomato seedlings a great starting environment. Coir is a bit pricier than other options, but the sustainability can’t be beat.

Plant Markers

If you grow more than a few plants each year, you’ll need a way to keep track of them. There are a lot of options out there so this one is 100% personal preference. You really just need something to write on that gives you a quick visual sign of what is growing in each tray. Options range from wooden popsicle sticks to colorful plastic markers. I prefer the plastic markers since they are reusable season to season.

Heat Mat

I have heard that some gardeners consider heat mats a vanity item, but I have found them to be invaluable for quick germination!

To germinate efficiently, soil needs to be kept around 68-85 degrees. When combined with a self-watering system, you have kind of the ideal solution. The heat mats warms the water in the reservoir so when it’s absorbed into the soil, it promotes the ideal temperature.

I also use my heat mat year round to help bread rise. My heat mats get pretty extensive use all year and are still going strong!

The DIY Solution

DIY Solution
This solution allows you to get creative and build your own unique process.

This solution will be perfect if you want to keep seed starting super simple and save money while doing it. If you search for DIY seed starting solutions, you’ll find some pretty creative options, like using egg cartons for seed starting!

People are really great about finding ways to reuse common household items or recycle things for garden use that would have normally been thrown away.

Lighting: South or West Facing Window

No matter how simple or complex your seed starting system is, light is a necessity. If you’re not using grow lights, you’ll need to position your seedlings in front of a well-lit southern facing window. A western facing window will do in a pinch, but it’s not ideal.

Seedlings need between 12-16 hours of light and you really can’t achieve that with western exposure. If your seedlings don’t get enough light, they will get leggy and fall over. Once this happens, it’s really difficult to recover and you usually have to start over.

If you don’t have good southern exposure but you don’t want to purchase a shelf grow light system, you can look at free standing grow lights. There are a number of options and price ranges out there that will help give your seedlings the amount of light they need.

Seed Starter ‘Trays’

There are a host of DIY seed starter tray options. If you do a search on this, you can find that people have successfully used eggshells, toilet paper rolls, egg cartons, wax-free paper cups, and even muffin pans!

Each of these has their pros and cons, so consider which option makes sense for your situation. My recommendation is to use one that easily allows you to transplant your seedlings into a 3-4” pot after they’ve grown enough. Most of the compostable options actually break down far before you’re ready to plant outside.

Whichever DIY solution you opt for, make sure to use plastic wrap over the tops while your seeds are germinating. This will produce the same greenhouse effect we mentioned earlier, but won’t require the purchase of plastic seed trays.

Seed Starter Mix

I still recommend purchasing a sterile seed starting mix or coconut coir for your seeds. This is not the place to skimp!

Plant Markers

You really can use anything you want to mark your plants. I have seen some cute craft ideas if you want to get kids involved. As long as you can tell what plant is in each container, you’re all set!

Step 3 – Planting Seeds

Planting Seeds
Plant two to three seeds in each seed trays.

Now that we’ve decided what kinds of tomatoes to plant, bought seeds, and set up our seed starting system, it’s finally time to plant our seeds! This is the part we’ve all been waiting for!

Seed starting mixes absorb a lot of water. Most bags will tell you to pour the bag into a container and moisten the entire thing prior to filling your seed trays. If you’re planting a lot of seeds at once, this is a very helpful step. If you’re only planting a few tomato seeds, just pour out as much as you think you need and wet it in a smaller container.

Fill the pre-moistened seed starting mix into each seed cell leaving roughly ½” of space between the top of the soil and the container. Compress it gently with your fingers and add a little more if needed.

Place 2-3 tomato seeds on the top of the moist soil and sprinkle a light layer of seed starting mix over them. Tomato seeds are pretty small and if you plant them too deeply, you’ll never see them again. Your goal is to sow them about ¼” deep. Sprinkling a light layer directly over the seeds gets you right where you want to be.

Lightly mist the top of the soil with a spray bottle filled with clean water. You don’t want to pour water over the top of newly placed seeds since it can wash them away or force them too far under the soil.

Place your seed markers into each cell so you know what type of tomato (or other vegetables or herbs) is in each.

Pro Tips

  • Planting multiple seeds in each cell will give you a better chance of germination. Sometimes you’ll have a seed pack where not every seed germinates. By planting multiples, you reduce the risk of having an empty cell!
  • Start your seeds indoors about 6-8 weeks before the last expected frost date in your area.

Step 4 – Daily Care of Your Seedlings

Tomato seedlings need care and attention every day. You won’t need to spend a lot of time checking in, but it’s important to have eyes on them often in the beginning.

Watering

Water With Spray Bottle
Water with a spray bottle until your plants are more established.

Seedlings need consistently moist soil. I have found that self-watering seed trays make this job incredibly easy. All you need to do is keep the reservoir filled and the job is done!

If you are using a more traditional seed tray, you’ll need to check the moistness of your soil each day. Things tend to dry out more quickly under grow lights, so this is really important.

Water the soil once or twice a day with a spray bottle. When your starts are more established, you can move to a teapot or watering can with a small hole.

Light

Seedlings in Windowsill
If using natural light, be sure to rotate your seed tray often.

If you’re using grow lights, the only thing you have to pay attention to is their height. As your seedlings grow, you’ll want to raise the grow lights to keep them 2-3” above the plants. If the lights are too close, the young leaves can become burnt. However, if you keep them too high, your seedlings will become leggy and fall over.

If you’re using natural light, be sure to rotate your seed tray every day or so to prevent all your seedlings from heavily leaning in one direction. Plants always lean toward the light, so you can prevent a weird growth pattern by simply shifting the tray around.

Air Circulation

Fans for Air Circulation
Good circulation is vital for your growing plants.

Air circulation is really important for seedlings. It helps them develop strong stems and it also helps ward off certain fungal diseases. A small rotating fan can be a great benefit here.

Make sure it’s far enough away from your seedlings that they don’t experience too much wind. But close enough that you can see them gently moving. Start conservatively at first, but as your tomatoes grow, you can increase exposure to the fan.

Step 5 – Germination, Thinning and Transplanting

I have always found a lot of joy and childish amazement watching my seedlings grow. From the first tiny green sprout that makes its way out of the soil, to the development of a tomato’s first true leaves, the entire process fascinates me. We’re witness to an entire lifecycle of a living thing and that is a special circumstance indeed.

Germination

Germination
Once your seedlings emerge, remove the plastic covering and place under grow lights, or in natural light by the window.

Germination is the sprouting of a seed after a period of dormancy, precipitated by the absorption of water, the passage of time, warmth, oxygen, and light exposure. When you see it written out like that, the germination of a tomato seed seems pretty special. And I can assure you that you will be delighted when you first see that green sprout break free of the soil!

After you’ve planted your final tomato seeds, cover the trays with a plastic top (or plastic wrap) to create a greenhouse-like environment. I like to use a heating mat at this stage to help with germination, but as we mentioned earlier, this is an optional step.

If you do use a heating mat, place it directly under your seed tray. This will allow the water and the soil to maintain the ideal temperature for germination and successful seedling growth. Remember, we are shooting for a soil temperature of 68-85 degrees.

Light isn’t necessary at this stage, but it will be once your first seedlings emerge. Tomatoes will usually germinate within 5-10 days of planting if conditions are optimal.

Once the first seedling emerges in each tray, remove the plastic covering and turn on your grow lights (or place in your southern window location). Place your grow lights 2-3 inches above your starts so they don’t become leggy. If you’re using a window, you’ll note that the seedlings lean toward the light. You’ll need to rotate the tray every couple of days to correct for this.

Thinning

Thinning
Choose your healthiest seedling and clip the others at the soil line.

Thinning seedlings is a bit of an emotional exercise, but it’s really important to the overall health and continued growth of your tomatoes. Remember when we planted 2-3 seeds in each seed cell?

If more than one of those seeds germinated, it’s time to choose the healthiest one and cull the others.  It sounds brutal, but if you don’t do it, there won’t be enough room for strong root growth and you’ll end up with a runty tomato seedlings that will never produce fruit.

You can start to thin your tomato seedlings once they have 2 sets of leaves. Choose the best looking seedling, and clip the others off right at the soil line with a sharp pair of scissors. Do not try to pull seedlings from the soil since that can disrupt the root system of the plant you will be keeping.

Transplanting

Transplanting Seedlings
Repot the seedlings in nursery pots to allow for healthy root growth.

Once your tomato seedling has 2-3 sets of true leaves (these are the actual leaves of the plant, not the cotyledon leaves the seedling first produces) you can think about transplanting them to a 3”-4” nursery pot. The first true leaf should arrive about 10-14 days after germination. Subsequent leaves follow shortly thereafter.

Repotting is important to encourage continued growth of your tomato seedlings. If you leave them in small seed cells, the plant would struggle to survive outdoor planting; the root system just wouldn’t be developed enough.

I like to repot my tomato starts in flexible 3”-4” nursery pots. These are made from flexible plastic that allows for easy release of the tomato plant when you’re ready to plant outside. It’s also just the right size for your young seedling to grow without feeling overwhelmed by too much space. If you want to grow specifically in pots long term, tomatoes need bigger pots as the season heats up.

Transplanting From Plastic Seed Tray

If you have chosen plastic seed trays or another non-biodegradable DIY solution, you need to remove the seedlings to place them in their new home. I use a spoon for this task, but you can also purchase a tool called a widger that is designed for transplanting seedlings.

Either way, gently push the spoon down one side of the cell all the way to the bottom. Pull up the spoon that is now cupping the tomato root system and gently place into the new pot. Hold the seedling by the soil and not the stem; otherwise you risk breaking the young stem from its roots.

Transplanting From Biodegradable Seed Tray

If you opted for a biodegradable seed tray like small CowPots or peat pots, your job is a little easier. Cut the cells apart from one another and then cut off the top part of the pot above the soil line. You will then bury the entire cell into your 3”-4” nursery pot.

Bury the Stem!

Bury Stem
Keep about two inches of stem above the soil line and bury the rest.

Tomatoes are unique because the plant can grow roots from any part of its stem that is buried underground. This is really helpful knowledge with seed starting, because invariably, some of your seedlings will seem leggy. When you transplant, you get to help the plant fix this.

First, remove any lower leaves on the stem, but ensure you leave at least 2 sets of leaves at the top. Fill your nursery pots with enough moist soil (I also use seed starting mix for this step) that the seedling will still have 2 inches of stem above the soil line when filled.

Place the seedling in the pot and fill in with more soil. Gently press down the newly added soil to ensure the seedling is stable and then water gently but thoroughly.

After you’ve finished transplanting, place your seedlings back under the grow lights (or by your southern exposure window) and continue your daily care habits.

Step 6 – Hardening Off

Hardening Off
Slowly begin to expose your seedlings to their new outdoor environment over a one to two week period.

So far, your tomato seedlings have lived in a very sheltered environment. Perfect temperatures, ideal light exposure, gentle breezes… This is a far cry from what your plants will experience in the great outdoors. 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 is important to protect your young tomatoes from wind in the first week of hardening off. After that, allow them to experience normal gentle wind currents, but move them if you’re experiencing extreme wind gusts.

Once you have hardened off your plants for 1-2 weeks, you can plant them in their final location and look forward to an abundance of fruit!

Step 7 – Planting Outside

Transplanting in Garden
Be sure to plant your seedlings outdoors after the last frost for your area.

We’re in the endgame now! You’ve done all the hard work to grow young tomato plants from seed and now you’re ready to put them outside in your garden. So when is the right time to do this?

The short answer is that you can plant your tomatoes outside once they have been hardened off and you are two weeks past the last frost date of your area.

With that said, every area has its quirks. Where I live in northern VA, we experience volatile springs. We may have a week or two of temperatures in the 70s or low 80s, but then have another 3 weeks of temperatures in the 50s. Because of this, gardeners in my area wait until Mother’s Day to plant tomatoes and other warm weather crops even though we’re technically far past our frost date.

If you’re unsure when to plant in your area, join a local gardening group and ask! Local gardeners are more than happy to help, especially when it may save you from a lot of heartache!

Just remember that tomatoes like to be outside once nighttime temperatures are above 60 degrees. If you plant them too early, they will not grow well.

Let’s Plant

Stake Your Plants
Stake each plant and water deeply after planting.

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. If you haven’t amended your soil at all, this is the time to do it. Add tomato fertilizer (designed for early growth) and some good organic compost to the soil.

If you used flexible nursery pots for the previous stage, gently squeeze the sides 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 from the pot. If you do, try watering the soil to moisten it more and try again.

If you used biodegradable pots, you’ll plant the entire thing into the ground. The only thing you’ll need to do is trim off any part of the pot above the soil line so it doesn’t stick out (just like you did with the first transplanting).

This final transplant is another opportunity to help the tomato grow strong roots. Remember, tomatoes will grow roots from any portion of the stem that is buried underground. I always trim off at least one set of leaves to allow me to bury the plant a little deeper in the ground. Feel free to trim off 1-3 sets of leaves as long as you leave 2-3 sets of leaves above ground.

Once the plant is as deep as you want it, cover the root ball with soil and gently press down with your fingers. Add mulch around the base of the plant to help it retain moisture and the water deeply. This is the time to stake your plants as well. Place your tomato cage carefully around the plant and press the tynes into the soil. This will allow you to stake your tomatoes without affecting the root system.

It’s a good rule of thumb to keep your newly transplanted tomatoes well watered for the first week after planting. This will help the plant settle in and encourage root expansion into the new soil.

Frequently Asked Questions

How Long Does it Take to Grow Tomatoes From Seed?

Growing tomatoes from seed takes about 6-10 weeks (depending on the variety) from sowing to transplanting outdoors. Starting seeds too early in the year can result in leggy or overgrown seedlings. Starting too late can result in having a later harvest. Aim to plant your tomato seedlings outside no sooner than 2 weeks after your last expected frost.

Should I Soak Tomato Seeds Before Planting?

Tomato seeds don’t need to be pre-soaked before planting. But if you’ve had a hard time germinating certain varieties in the past, its worth a try. If you choose to do so, soak the seeds in warm water the night before planting to soften the hull and help the sprout break through.

Why Have My Tomato Seeds Not Germinated?

Tomato seeds need a goldilocks environment to sprout. The soil needs to be between 68-85 degrees and kept at a consistent level of moisture.

Moisture is easy to correct for (and visually see), but if your soil is too cold, none of the other factors will matter. If you have done everything right but your seeds still haven’t germinated, look at the age of the seeds. Older seeds have a much lower germination rate.

How Many Tomato Seeds Should I Put in One Hole?

When planting tomatoes from seed, you should always aim to plant 2-3 seeds per seed cell. This will give you some backups in case you don’t achieve 100% germination.

Do Tomatoes Need Sunlight to Germinate?

Nope! Tomato seeds don’t need sunlight to germinate, but they do need the right soil temperature! As soon as you see a single sprout pop out of the soil, move the entire seed tray under the grow lights or near a southern facing window.

Should You Cover Seeds When Germinating?

Yes! Covering your seed trays with a plastic dome (or even plastic wrap) will speed up the germination process. The plastic dome creates a greenhouse environment that keeps the seeds happily moist. Remove the dome as soon as you see the first sprout break through the soil.

Should You Water Seeds Right After Planting?

Yes! Seedlings need to be kept in consistently moist soil until they are more established. Young plants have not developed an extensive root system yet so they need to be continually supplied by you.

On the other hand, be sure that your seedlings are planted in well draining soil so the roots aren’t sitting in water. This can cause a variety of diseases that will kill your seedlings before they ever make it outside.

Final Thoughts

As you can see from the length of this article, growing tomatoes from seed requires some equipment and preparation. Know that you will make some mistakes in your first season. You will lose some plants. You will get frustrated.

But despite all that, you will feel so elated when you harvest the first tomato off a plant that you grew from seed! I promise that no fruit will have ever tasted sweeter. So roll up your sleeves, have fun, and get planting!

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