Growing Tomatoes in Pots

Have you always wanted to grow your own vegetables but kill them every time you try? Follow my step by step guide and in no time you will see how easy it is to grow your own vegetables at home. I even made a free shopping list to bring to the store with you. What are you waiting for?

Juicy Red Tomatoes

Growing tomatoes in pots is a great way to maximize available space in your yard or on your balcony. The best part is you get to enjoy the benefits of growing your own produce. And it takes a lot less work than having a full garden in the long run.

A container garden simply refers to a garden where your plants are grown anywhere other than in the ground. The terms pot or container mean the same thing for my purposes today; something to contain soil and allow you to grow vegetables by yourself.

Why Should You Try Growing Tomatoes in Pots?

So why do this? Maybe you are like me and have maxed out your garden space but want to plant a few more potted tomato plants. Or perhaps you have never been able to keep even a simple house plant alive and want to try again because 2020 is the year of starting a garden.

Either way, growing tomatoes in pots is a great way to use any available space you have at home for growing your own produce. It is also fun to teach children where their food comes from.

Added bonus you get to enjoy fresh picked vegetables right out of the garden. Plus, once you have had a garden fresh tomato you will never go back to supermarket tomatoes again!

Let me walk you through the process step by step of how to start a container garden. I am doing this myself by growing tomatoes in pots this year, and will guide you through it. To do this there only a few materials you will need. You may even have some of these on hand at home already.

Selecting a Container for Growing Vegetables

You can grow vegetables like tomatoes in any type of container or pot, even something as simple as a five gallon bucket. An important factor is the typical weather in your area. In Chicago our spring weather can be wet and our summer weather can be hot.

A traditional raised bed garden can handle changing weather conditions. At most you may need to add a little mulch to help retain moisture when it gets really hot outside.

A container on the other hand will be a small self-contained garden so you need to help it adjust to the conditions. Important point: any container you use has to be able to drain at the bottom.

I made the mistake of using a pot with no drainage holes years ago. My container tomatoes ended up growing in swamp like conditions for periods of time. That did not end well.

When selecting a specific type of container there are a couple of considerations. Terra cotta pots are more porous meaning they will absorb water from the soil so you many need to water more frequently. Dark color pots will absorb and retain heat which could be too much for your little plants to handle in hot weather.

Avoid treated wood in any situation where you are growing plants to consume, whether for your garden or container. Otherwise essentially any container or plastic pots will do.

You can also get some fabric pots on Amazon for pretty cheap. At last check you could get five pots for just $20 which is a pretty good deal. I already had a few plastic pots laying around that I purchased earlier so I’ll be using these but I’d suggest giving the fabric pots a look as well.

Choose the Correct Container Size

Size matters for growing tomatoes in pots. Plants have a surprisingly large root system that can extend at least as far below ground as the plant does above it. At a minimum you will want a 12 inch diameter container, but bigger is better.

Look for 16 or even 20 inch diameter containers. The University of Illinois has a great guide to help you decide depending on which vegetable you plan to grow. I was actually surprised to see they recommended planting two pepper plants in a two gallon container.

12 in pots to plant tomatoes this year
This year I am growing vegetables in 12 inch pots

Best Soil For Growing Tomatoes in Pots

Many online sites recommend using potting soil or a potting mix for a container garden. Potting soil is composed of equal parts peat moss and perlite.

Perlite is the little white pellets in potting soil. These pellets hold moisture and help prevent the soil from compacting. Peat moss is essentially the bulk part of the potting soil mixture.

Potting soil is a simple and easy solution for growing tomatoes in pots or containers. In my experience potting soil alone is not great for a full growing season. Despite the name there is no soil in potting soil so there are no nutrients other than the fertilizer added by the manufacturer.

You will need to remember to fertilize quite often if you choose potting soil. Like weekly starting a few weeks after planting. Potting soil also dries out very quickly if you have not had rain in a few days. Build some better soil and reap the benefits later this summer.

Make Your Own Container Garden Soil: Option 1

I use the same type of soil in containers that I use in my raised bed gardens; roughly equal parts of peat moss, compost, and perlite or vermiculite (same basic properties as perlite).

This is a great option if you are already adding to or amending your existing raised bed garden; you will likely have leftovers of all three anyway as each come in large one or two cubic foot bags. You can make little mini mixes for your separate containers.

As an added bonus, at the end of the season just empty the container soil back into your garden for easy clean up.

Make Your Own Container Garden Soil: Option 2

We call this pushing the easy button. Make your own mix with about 33% compost and 66% potting soil. 

Recall that potting soil is just peat moss and perlite, so this is about the same mixture as option #1. Going this route allows you to buy smaller quantities if you are only doing a container garden or do not need large amounts of soil.

I will be using option #2 myself for this example. My raised beds are already built for this year and I have some leftover compost at home. You can still dump this soil into your main garden at the end of the season if you have one.

Fertilizer for Container Vegetables

If you are someone who freely admits you do not have a green thumb I bet this is where you have gone wrong in the past. Any soil around your yard or in your garden naturally contains nutrients from broken down plants, leaves, worm casings, etc.

This soil probably still needs to be amended but it will have nutrients to feed your plants initially whereas potting soil is by definition soil free (I know it makes no intuitive sense) and thus nutrient free.

Even raised bed gardens need monthly infusions of fertilizer during the growing season. This helps you plants make it through the long summer and stay continuously fed.

All fertilizers will have a number on the front of the package like 10-10-10 or 5-10-5. You may also see this listed as N-P-K. Let’s briefly explore what each number or symbol means to help you select the best fertilizer for your container vegetables.

Nitrogen (N)

Nitrogen is the first number in the series and is represented by a “N” on the fertilizer label. It is a main component of chlorophyll, used by plants to produce energy from sunlight. Chlorophyll is what makes plants and your lawn green.

Nitrogen in fertilizer will help support plant growth and structure. If you are growing greens like lettuce in a container you will want a high nitrogen fertilizer, one where the N or first number is the highest.

Phosphorus (P)

Phosphorus is the second number in the series and is represented by a “P” on the fertilizer label. It is essential for flowering and root growth. So it makes sense that while lettuce (or your lawn) needs a high nitrogen fertilizer because you want to maximize the growth of the green leaves.

Flowering vegetables like peppers and tomatoes need phosphorus for optimal production and root health.

Potassium (K)

Potassium is the third and final number in the series and is represented by a “K” on the fertilizer label. It strengths a plants ability to fight off disease and plays a role in increasing crop yields. It also strengthens the root system and helps plants adapt to colder or dry weather.

What is the Best Fertilizer to Choose?

Regardless of which fertilizer you choose, look for an organic fertilizer. This type of fertilizer not only nourishes plants it also helps to enrich the soil at the same time.

Many synthetic fertilizers are just focused nutrients which are more easily absorbed but it’s like taking a multivitamin vs. eating whole foods. You want the nutrients in the whole package, not just in concentrated form.

If you want to get fancy with your fertilizers, apply a small amount (like ½ to 1 tablespoon) of higher nitrogen fertilizer to your container at the time of planting like Plant-Tone by Espoma. Every month after you have planted apply a lower nitrogen fertilizer like Garden-Tone for best results throughout the growing season.

Picture of garden tone fertilizer for your home garden or container garden

Basically you are following the same fertilizer schedule as you should use with an in-ground garden because you are using the same soil. You can also just apply the Garden-Tone fertilizer from the start if you want one product for the season.

Espoma also makes a specific fertilizer for tomatoes called Tomato-Tone that works really well, but the Garden-Tone will work on tomatoes too. Just remember less is more with fertilizer, over feeding will kill your plants.

Step by Step Instructions To Grow Tomatoes in Pots

Start by printing out this shopping list then head to the store. You will need the proper pots that have the ability to drain, one for each plant you plan to grow. You will need enough soil to fill each pot with a mix of compost and potting soil plus a bag of fertilizer. And of course the plants you want to grow!

Free Shopping List

Step 1: Lay Out Everything, Fill the Pots

When you are ready to plant, lay everything out so you do not have to keep making trips to the garage or shed.

Items needed to plant tomatoes in pots

Now let’s fill those pots with soil. Since we are using option number 2 from above and creating our own garden soil mix, we need to do a little mixing before we are ready to plant. I like to keep old pots in my garage and they work well for tasks like this. Or simply use you garden trowel.

Mix two pots of potting soil for every one pot of compost until your pot is about 90% full. Then use a trowel or your hands and thoroughly mix the soil. They should look like this when you are done.

Mixing dirt to plant tomatoes

Step 2: Plant Your Tomatoes

Now make a small hole, large enough for the root ball, and drop your plant in. Fill in the hole and gently press down the new soil.

tomato plant ready to be planted in pot

Step 3: Water Your New Plants

Water in your new plant and you are done!

its this easy and now you are growing tomatoes in pots

Best Tomato Varieties to Grow

When I grow tomatoes I find I am overly ambitious in spring because the plants are so small. I have learned over the years not to grow too many plants; now I will grow one or two cherry tomato plants and one or two full sized tomato plants. At their peak you will be giving them to neighbors if you plant too many.

This year I am growing Arkansas Traveler tomatoes as my main large tomato plant. I grew this last year and they were quite prolific, I had a ton of medium sized juicy tomatoes all summer long.

Cherry tomatoes work particularly well in containers. I find they are more compact that full tomato plants and with regular fertilizer application remain productive all season long.

I choose Sweet Million and Sun Sugar cherry tomatoes to grow at home in 2020. The Sweet Million plant is pictured above in the pot and the Sun Sugar is in the ground.

Additionally I like to grow several varieties of mild and sweet peppers beyond just the traditional bell peppers both in the garden and in containers. Peppers I have enjoyed in the past and have already currently planted this year are Giant Marconi, Melrose, and of course Red, Orange, and Yellow Bell Peppers.

When to Grow Tomatoes in Pots?

As a rule of thumb I do not plant warm weather vegetables (cucumbers, peppers, tomatoes) until about May 15th unless we are having a warm spring. Then I may sneak them in earlier.

What’s nice about growing tomatoes in pots is that you can plant earlier if it is warm out at the beginning of May. This allows you to move them indoors if the temperature dips too low after you planted. Summer vegetables hate temperatures below 45 degrees.

Also, because of the short growing season in Illinois, I like to use vegetables plants from a garden center as opposed to starting seeds. You certainly can plant seeds and they may do well eventually. Using an established plant will give you at least a two or three week head start on harvesting produce.

How Often Should I Water My Tomato Plants in Pots?

You have to water container vegetables often, likely more often than anything growing in your garden as the container will run hotter and thus water will evaporate faster. Check the soil with your finger. If the top inch is dry then it’s time to water.

Try to water early in the morning so your plants can absorb that water and the leaves can dry during the day. Excess water at night can lead to mildew and rot. Admittedly it rains at night and gardens tend to survive so it’s not the end of the world if you forget. It is just optimal if you can time the water delivery to the morning hours.

Remember, Container Vegetables Need Lots of Sun

Last point. Most summer garden vegetables love the sun. This is probably one of the best parts of container gardening, you can squeeze a container or pot into almost any small space that gets a lot of sun.

A full six to eight hours is best for bell peppers and tomatoes. If you are not sure where your sunny spots are in your yard mid-May is a great time to go outside and assess. Check on a sunny day and assess every hour or so. Make a note of where your sunniest spots are and start to make a bit of room for your containers.

Have fun and let me know how it goes!

Author: Matt Knight RD, LDN

Matt works hard to share his knowledge of nutrition and help empower his clients to take control of their health with food choices that best support their specific health condition. Click here to learn more about Matt.

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