Once you learn how to grow tomatoes from seeds, you'll look forward to growing them every summer!
You don't need a lot of space to grow tomatoes, either.
Whether you're growing in a backyard or balcony, these tips for growing tomatoes in pots and raised beds should help you out.
If you ask a gardener what their favourite vegetable to grow is, they're probably going to say tomatoes!
It's one of the most popular crops that people grow in their backyard gardens for a reason - homegrown tomatoes just taste better!
While most varieties of tomatoes are quite large and need a lot of space, there are options for anyone who's growing on a balcony or patio, too. I'll dive into those with you in a bit.
First, let's take a look at what tomatoes need to grow well.
🌿 Growing Requirements
Weather: Warm. Best grown in summer (but start them in Spring)
Sunlight: 6-8 hours of direct sunlight (full sun)
Water: Moderate. Water deeply a few times a week, but more often in hot weather.
Spacing: At least 30 cm (12 inches) in raised beds for most varieties. Follow seed packet or seedling label instructions.
Soil: Potting mix for vegetables (i.e. ProMix Organic). Best amended with compost and an organic all-purpose fertilizer.
Start Seeds Indoors or Direct Sow: Start indoors.
🤔 Choosing the Right Variety
Tomatoes are one of the most fun vegetables to grow from seed, because they are so many different kinds out there! This is one situation where there really is something for everyone.
I'll be honest with you, I hated tomatoes for most of my life. But I'll happily eat any of the ones that I grow in my backyard!
The sheer amount of options is a wonderful thing, but it can also be overwhelming when you're just starting out. So let's break down the options a bit.
What's the Difference Between Determinate and Indeterminate Tomatoes?
A determinate tomato plant is short in size, usually about 0.9-1.2 meters (3-4 feet). These stocky plants set all of their fruit at once, producing over a span of a week or two, and then they're done for the season.
An indeterminate tomato plant can get very tall, measuring anywhere from 1.82 cm - 3.0 meters (6-10 feet), although they can get bigger in certain situations. These plants will grow and produce fruit all summer until they are killed off by cold weather.
Tip: An easy way to remember the difference is that determinate tomatoes grow to a determined size!
Which Variety Should I Grow?
The first question you need to ask yourself is, what do you like to eat?
If you like the idea of snacking on ripe tomatoes whilst walking through your garden, plant cherry tomatoes.
If you're dreaming of plump juicy tomato slices to top on freshly grilled burger, maybe beefsteaks or slicers are for you.
Not sure where to start? Check out this list of my favourite tomato varieties!
Next, think about how much space you have available to plant in.
If you're planting in a raised bed, or in fabric grow bags, you can pretty much plant whatever you like.
If you're limited in space, or if you're growing on a balcony or patio, you'll want to look for seeds (or seedlings) that are labelled as "container friendly" or "dwarf"
One variety that works particularly well in very small containers is the Red Robin tomato, which you can purchase from West Coast Seeds.
Where to Plant Them
Tomatoes are native to South America, which is why they LOVE sunshine and warm weather. Unlike cold-hardy vegetables (like lettuce), tomatoes can easily be damaged by frost.
If you're planting tomatoes in your backyard, pick a spot that gets at least 6-8 hours of direct sun. Or as close to that as you can get.
Obviously tomatoes grown in a raised bed won't be able to be moved once planted. However, if you plant your tomatoes in a pot you can easily move it into a sunny area as needed.
🪴 Growing Tomatoes in a Pot
When it comes to tomatoes, size matters.
Most cherry tomatoes need a pot with about 30 cm (12") of depth to grow well.
If you choose to grow a larger variety of tomato (like a Roma), you'll want to go with at least 60 cm (24") of depth instead.
Basically, the larger the tomato, the more space it needs.
All tomatoes benefit from being planted deeply, so err on the side of the pot being too deep rather than too shallow.
Another thing to think about is the material that your pot is made of. For example, terra cotta looks really nice, but can dry out very quickly.
Fabric pots are a great option for large tomatoes, but for dwarf size plants plastic has worked better for me.
Growing Tomatoes from Seeds
If you live in a cold climate, it is essential to start your seeds indoors if you want to grow your tomatoes from seeds.
Otherwise, the cold fall weather will arrive before you have a chance to harvest anything! You'll want to start your tomato seeds about 6-8 weeks before your last frost date.
While growing tomatoes from seeds isn't necessarily difficult, you do need a few pieces of equipment to ensure your success.
First, I strongly recommend that you invest in a grow light.
Tomato seedlings need a lot of light as they're growing, or they become "leggy" (which just means they're overly tall and weak). In my experience, a sunny window just doesn't provide enough light for tomato seedlings to grow into strong plants.
Secondly, a heat mat can really improve your germination rates. I start my seeds in a cold basement, so having a heat mat under my seed starting trays is essential for me.
A humidity dome also helps, and is less expensive than the mat.
For the sake of not making this article too long, please check out my blog post on how to start seeds for detailed instruction on seed starting!
You will need to raise your baby tomato plants indoors until the risk of frost outside as passed, and overnight temperatures are consistently warm (about 15°C/59°F).
Since the plants will be indoors for a long time, you will need to "pot them up" into bigger containers until they are ready to go into their permanent home.
I do not recommend planting tomato seeds directly into the ground unless you live in a warm climate with a long growing season (more than 90 days).
👩🏽🌾 How to Plant Tomato Seedlings
Once you've grown your tomato plant into a seedling, you'll need to harden it off and then, eventually, plant it outdoors.
(Even folks who don't want to grow tomatoes from seeds will need to learn how to plant a seedling!)
A seedling (sometimes called a transplant) is simply a baby plant that you grow yourself, or buy from a garden centre or nursery.
Some people like to start their tomatoes from seedlings, because it saves you all the work of having to start and nurture the plant from seeds.
The downside of buying seedlings is that they can be more expensive, and there are less varieties available, compared to growing from seed.
Once your tomato plant is hardened off, and the outdoor temperatures are warm enough, you can plant your tomato seedling into its forever home.
Here's how to plant a tomato seedling, whether you grew it yourself or bought it:
- Dig a deep hole in the soil large enough for the width of your seedling or add container soil to the pot that you will be using. You're going to plant 1 tomato per container, or per square foot in a raised bed.
- Add a handful of worm castings to your container or the section of the raised bed that you will be planting in.
- Add an all-purpose fertilizer to the soil according to package instructions. Mix well.
- Trim off the bottom leaves from the stem of your tomato, so you can plant it deeply.
- Remove your seedlings from its container, and place into the hole. Fill soil back into the hole and press it down around the plant with your hands.
- Water the plant well to help the roots establish.
💩 Which Fertilizer to Use
I grow all of my edible plants in ProMix Organic potting mix, which already has some plant food built into it.
Additionally, I like to add Gaia Green all-purpose fertilizer to the soil, as well as a handful of Gaia Green worm castings (a.k.a. worm poop).
For large vegetables, like tomatoes, that are "heavy feeders" (meaning they need a lot of nutrients from the soil), it's also a good idea to add a bagged compost.
I know a lot of us don't have the space to make our own compost, so buying a pre-made option is our best bet.
💦 How to Water
Watering tomatoes at the base of the plant (at the root) is a best practice, but I don't get too hung up on not letting the leaves get wet.
If you keep your under canopy area clear, and cover your soil with a layer of mulch, you're probably not going to have to worry too much about diseases that are spread by watering overhead.
Also, tomatoes require consistent watering to maintain their flavour and shape.
Big fluctuations in moisture levels can cause your tomatoes to crack. Also, poor watering can lead to blossom end rot, where the tomato literally begins to rot from the blossom end of the fruit.
Water your tomato seedlings daily until established, and then water deeply a few times a week.
When the plants are flowering, or if the temperatures are very hot, you should water daily (or even twice a day) to avoid letting the plant dry out.
Tip: Adding straw mulch around your tomato plants, and watering at the base of the plant, can protect them from soil-borne diseases.
✂️ How to Prune a Tomato Plant
Remember how we talked about determinate and indeterminate tomatoes earlier?
When it comes to pruning, you don't really need to prune the determinate plants very much.
However, indeterminate plants can get out of hand quickly if you don't stay on top of your pruning.
Pruning the Under Canopy
The first thing to do, once your tomato plant has gained some height, is prune off the bottom branches along the stem.
You can do this on both determinate and indeterminate plants (but I remove less from the determinate plants)
This technique increases the air flow around the plant, which helps prevent diseases. Also, since no branches will be touching the soil, you're less likely to encounter soil-borne diseases.
Start by taking a few branches off at a time as the plant grow.
For determinate tomato plants, I like to just remove any branches that are touching the soil, leaving about 6 inches of space clear above the soil.
For an indeterminate tomato plant, I like to have about 30 centimetres (12 inches) of bare stem at the bottom of the plant.
Removing Suckers from the Elbows
Next, and only for indeterminate tomatoes, you'll want to remove any "suckers" in the "elbows".
What does that mean?
Basically, the suckers are shoots that develop in between two branches. You can find them by looking for a shoot that is growing at a 45 degree angle in between two other branches that make a v-shape (or an "elbow").
(Watch my YouTube video above to see an example of what I'm talking about)
Unlike regular sun leaves, suckers turn into fruit-producing branches. This means that they pull energy from the plant to create flowers and fruit.
Having a few suckers on your plant will give you many tomatoes. However, some people like to remove almost all of them in order to get larger tomatoes.
I generally prefer to have more smaller tomatoes than just a few large ones, so I leave quite a few suckers on my indeterminate tomato plants. I do take some of them off though, in an attempt to keep the plants tidier.
🔪 How to Harvest
It's usually a good idea to harvest your tomatoes before they are completely ripe.
This might sound counterintuitive, but if you allow all of your tomatoes to ripen on the vine before you harvest them, there's a good chance that they will become overripe before you get to them.
Overripe fruits will get mushy and fall off the vines, which is not only a shame, but can also attract pests (like mice).
Instead, it's recommended to wait for the tomatoes to turn from green to their final colour (which depends on the variety). Then start checking the firmness of the tomatoes.
Tomatoes are very hard at first, and will begin to soften as they ripen.
When your tomatoes have good colour, and have a little bit of "give" when you (gently!) squeeze them, you can harvest them.
Smaller tomatoes tend to ripen more quickly than large ones. Grape and cherry tomatoes should be harvested as soon as they have turned colour, or they are likely to crack and fall off the plant.
Be careful not to remove large tomatoes until they have a good amount of colour and at least slight give, or they will not fully ripen on your counter before they start to spoil.
(At least, that's been my experience)
Tip: Sungold tomatoes should be allowed to ripen on the vine for best flavour.
🍅 How to Prepare and Store
To harvest a tomato, gently twist and pull the tomato off the stem.
If you're worried about damaging other fruit that is not quite ready to be harvested yet, you can cut the tomatoes off with garden shears instead.
When tomatoes are ripe, they should come off the stem very easily.
Store unripe tomatoes upside down on your counter top. While it might look weird, this technique held to retain the tomatoes moisture as it ripens, and can help prevent molding.
Do not put unripe tomatoes in your fridge - they will not continue to ripen.
Some people also don't like to put ripe tomatoes in their fridge, claiming that it can alter their flavour and texture.
However, ripe tomatoes can spoil quickly at room temperature.
If you need an extra day or two before you'll be able to enjoy your tomato, stick it in the fridge. Just be sure to give it some time to come back to room temperature before you slice into it.
🙋🏽 Frequently Asked Questions
Smaller tomatoes, like cherry tomatoes, can usually be harvested about 60 days after planting. Larger varieties will take about 90 days.
Tomato plants thrive on warm weather, nutrient-rich soil, and consistent watering. Regular pruning will keep your tomato plants tidy, and can help prevent diseases.
If you live in a cold climate, you need to start your tomato seeds indoors 6-8 weeks before your last frost date. This is usually in March or April, depending on your plant hardiness zone.
If you would rather plant a seedling from the garden centre, you can plant them in the ground when the threat of frost has passed, and your night temperatures are consistently warm. This is usually in June or July, again depending on your planting zone.