If you are looking for the perfect vegetable plant to grow on your patio or in the backyard, look no further than tomatoes. Most are easy to grow and offer a wide range of types and flavors.
Perhaps the easiest beginner tomato variety is the cherry tomato. In this article, I’ll provide a complete guide to growing cherry tomatoes in pots. By the end, you can look forward to having bountiful yields from just a single tomato plant on the porch!
We’ll cover everything you will need to know to grow a healthy container cherry tomato plant. From selecting a seed variety, to planting seeds indoors, using grow lights, fertilizing, transplanting outdoors and eventually harvesting fruits. Let’s get started growing cherry tomatoes!
In this article (skip ahead):
- When to plant seeds
- How to germinate seeds
- Using grow lights
- Tips for seedlings
- Transitioning outdoors
In the late winter, I like to make sure I have all of the supplies I will be needing for the growing season. It is nice to know that all the necessary supplies are already on hand for each growth stage.
This list will set you up for success when growing any tomato variety in a container. While some of the items are optional, like a grow light, each will help improve growth rates and the overall health of your tomato plants.
- Seed cell trays & humidity dome
- 3 inch pots
- 10-12 inch pots
- Seed starter mix
- Potting mix
- Grow light
- Spray bottle
If budget is your most important factor, you can get away without using a grow light or seed starter mix. These will help improve early growth rates and the long-term sturdiness of the plants. However, tomatoes will grow well enough in a South-facing window.
If you do not already have seeds, I recommend looking for the most suitable variety for your needs. There are many types of cherry tomatoes to choose from, so pick wisely!
Choosing a Variety
For cherry tomatoes grown in pots, you might want to consider whether to plant a determinate for an indeterminate variety. The type will usually be denoted on the seed packet or the description when purchasing online.
Determinate plants will reach a mature size, set flowers and products one large set of fruits all at once. The plants also tend to be smaller and require less pruning than indeterminate plants. This makes them well-suited for growing in containers.
Indeterminate tomatoes continue producing fruits on an ongoing basis until the weather becomes too cold. This makes them great for steady harvests and regular usage. However, they also grow taller and require more rigorous pruning and trellising.
Learn more about determinate vs indeterminate tomatoes here.
With all of the necessary supplies in hand, you can determine when to plant seeds indoors.
When to Plant Seeds Indoors
Timing is everything! Tomatoes require a pretty long growing season to produce ideal harvests, so it is important to start seeds indoors in early spring. This gives the plants a head-start and effectively elongates their lifespan by a few weeks.
In short, tomato seeds should be sown indoors 4-6 weeks prior to the last risk of frost. Once the weather warms up, tomato plants can be gradually introduced to the sunlight until they move outdoors permanently.
To give one example, here in Zone 6, our last frost date is around May 15th. I plant my tomato seeds indoors some time in the first 2 weeks of April. This allows enough time for the seeds to germinate and grow strong before hardening off.
How to Germinate Cherry Tomato Seeds
Tomato seeds require 3 basic elements for successful germination. These include moisture, warmth and oxygen. Thankfully, most of us have these things available at all times of the year.
Once you have determined when you will plant, the sowing process is easy! We recommend using a seed starter mix like this one on Amazon instead of regular potting mix. These do not contain nutrients, but rather a well-aerated medium that the young root systems will love.
How to plant tomato seeds:
- Pre-moisten seed starter mix. In a large container, like a bowl or bucket, pre-moisten enough seed starter mix to fill your seed cell trays. Mix the seed starter mix thoroughly so that it is evenly moist but not dripping wet. The amount required will depend on the number of plants you are growing. If it is just a few, you may only require a quart of soil or less.
- Fill seed cells and pack. Add the moistened starter mix to your seed cells and press down with your fingers. When you feel some resistance, stop compressing and add more of the mix to top off the cells.
- Plant 1-3 seeds per cell. Using a pen or pencil, make a small divot about 1/4″ deep in the center of each cell. To ensure that at least one of the seeds sprouts successfully, I like to plant 2-3 seeds per cell. If your supply is limited, you can take a risk and plant just one. Or, if multiple plants sprout, you can divide the seedlings later.
- Cover with 1/4″ soil. Cover the seeds with surrounding soil and lightly compress.
- Mist surface with water. To ensure the seeds are adequately moistened, spritz the surface of the soil several times until it is wet. This helps nestle the seed in its new home and initiate germination.
- Cover with humidity dome or similar. To keep things moist, use a humidity dome or similar to enclose your seed cell trays. Many trays come with a dome, but you can also just use a light fitting plastic baggie, plastic wrap, or a spare food container lid.
- Place in a warm place. Tomato seeds will sprout best in temperatures between 70-80°F (21-25°C). If your home is cooler than this, try placing the trays on top of the refrigerator for extra warmth. Light does not matter before the seeds sprout, so don’t worry if it is dimly lit!
- Fan out daily. Check in on the seeds daily to fan out the trays and provide fresh air. In ideal conditions, tomato seeds will sprout within 5-7 days. Once 50% of the seeds have sprouted, it is time to move them into the light!
When your cherry tomato seedlings sprout, remove the humidity dome and place the seed cell trays under grow lights. If you do not have a grow light, find the most sunny window available and turn the trays daily for even sun exposure.
Using Grow Lights for Tomatoes
Countless gardeners simply use a sunny window to grow their tomato seedlings indoors. While the plants will almost definitely survive, they will get off to a much better start if you use a grow light.
There are many levels of grow light options, from cheap clip-on lights to expensive professional units. If you just grow a few plants, I would recommend something inexpensive and unobtrusive, like this light from Amazon. But don’t expect it to last very long!
If you have dozens of tomatoes and other early-start plants (like peppers), you may wish to invest in a long-term light. I use the ViparSpectra Pro Series LED light, and it works wonderfully.
LEDs are great for their relatively low energy consumption, silent operation and durability. ViparSpectra lights are especially attractive for their water-resistant design, dimmer knob, and competitive pricing.
There are also more affordable fluorescent lights available. These lights are cheap, but they also tend to burn out quickly, requiring frequent bulb replacements. They also need to be placed much more closely to your seedlings than LED lights.
Note: If you use fluorescent lights, try to get one warm bulb and one cool bulb for best results.
Tips for Growing Seedlings
Once your tomatoes sprout, it is important to give theme everything they need. This includes light, water and nutrients.
- Bottom water. Pour water beneath your seed cell trays and allow the soil mix to wick up water. Once the surface of the soil is moist, pour out any excess water in the reservoir to avoid overwatering.
- Begin fertilizing at 1/2 strength after ~1 week. I like to use organic fertilizer for young plants to avoid the possibility of nutrient burn. Use something water soluble and apply it during watering. Once the plants are transplanted to larger pots, you can increase to full-strength fertilizer (more fertilizing info below).
- Keep plants around 15″ from LED lights. If you have a powerful LED (~100W), 15″ is usually recommended for tender young tomato plants. If you are using fluorescent bulbs, you should bring the plants much closer, around 3-4″ if possible.
- Provide 12-16 hours of daily light. Young seedlings will grow best with lots of daily light. I recommend providing 16 hours of light daily, and 8 hours of darkness.
- Provide a gentle breeze. I like to use a small oscillating fan to provide a gentle airflow. This provides fresh air, but can also strengthen the young stems early on.
Grow lights are not required, but are highly recommended for the best results. This is especially true if you are trying to grow lots of tomato plants.
Transplanting Cherry Tomatoes
After around 3-4 weeks of growth, your tomato seedlings will be ready to move out of their tiny seed cells and into slightly larger pots. This gradual increase in soil space is important for steady, fast growth rates.
You may also transplant directly into a large pot, but just know that this can cause stunted growth. I recommend first moving the plants into a 3″ pot (or similar size) and allowing an additional few weeks of growth there. Then, the plants will be the right size to move into pots.
Transplanting is essentially the same as planting seeds, but instead of a seed, you will move the seedlings (soil and all). The process requires preparing potting soil, filling the new pots, digging a hole to accommodate the seedling, and moving the plant.
- Prepare potting mix. With this transition, we’ll move the tomato plants into normal potting mix. You can use organic Fox Farm Happy Frog, or a generic brand from your local nursery. Anything that has a good mixture of organic material, water retention and drainage will work. Pre-moisten the soil evenly with water until it is moist but not dripping wet.
- Add soil to 3″ pots. Fill each pot with the prepared soil. Compress until you feel resistance, and then add more soil to top it off. Tip: Always label your pots before transplanting to keep organized!
- Create a hole in soil. Using your finger, open a hole in the soil that is large enough to accommodate the seedling cell plugs.
- Remove seedlings from seed cell trays. Use your thumb and fingers to gently squeeze the seedling cells from the outside. This will loosen the seedling’s soil and make it easier for it to be removed. Turn the trays sideways and gently slide the root ball from the seed cell.
- Transfer plant to 3″ pot. Plant the seedling slightly deeper than it was in the original seed cell, about 1/2″. Tomato stems will not rot when planted deeper, but instead will produce more roots for a sturdier plant. Cover with soil and compress lightly.
- Water thoroughly. Give the plant a thorough watering around the base of the stem and ensure the roots are moistened.
- Return to grow lights. Once the transition is done, move your cherry tomato plants back under grow lights (or back to the sunny window).
At this point, you should begin providing full-strength fertilizer to your tomato plants. They are strong enough at this age to handle the nutrient and will use them to grow faster.
Fertilizing Cherry Tomato Plants
Since tomato plants are so popular, there are specific fertilizer blends that are made for the plants. Tomatoes grow very fast and require lots of nutrition to produce at their best.
In this section, I will break down my fertilizing technique into two major growth stages: Early growth (from seedling to transplanting outdoors), and fruiting stage growth (when the plants are producing tomatoes).
Read more about the best fertilizers for tomatoes here.
Early Stage Fertilizer
During the early months, tomatoes require lots of nitrogen to grow healthy foliage, roots and stems. For this reason, I recommend picking a fertilizer that has a relatively large N number on the N-P-K rating.
Note: As stated before, very young tomato plants do not require as many nutrients. If you over-fertilize, the plants may burn or become severely stressed. For this reason, I recommend a gentle organic fertilizer, like this seaweed fertilizer, while the plants are in the seedling cells. This way, if you overfertilize, the plants will likely survive.
Once the plants are transplanted into 3″ pots (3-4 weeks old), then you can begin fertilizing at 100% strength (as the specific product recommends).
For example, this tomato fertilizer has 9% nitrogen, perfect for strong leafy growth. However, this number may be too high for the fruiting stage, potentially leading to a lack of flowers and fruits.
Fruiting Stage Fertilizer
Once the plants are hardened off to the outdoors, then you may wish to change your fertilizer regimen to reduce nitrogen. If you do not wish to change anything, the previously mentioned Miracle-Gro Organic is a great option for all-season fertilizer.
For a great fruiting stage fertilizer, look for high phosphorus and potassium levels, with a lower nitrogen percentage. Fox Farm’s Tiger Bloom is great for this, though it is not completely organic.
Follow the manufacturer’s recommended application rate through the season. If you have excessive flower/fruit drop, consider how much nitrogen you are applying and consider reducing.
Transitioning Plants Outdoors
Once the outdoor temperatures are consistently above 50°F, your tomato plants can live outdoors. However, transitioning the tender plants into full sun should be done gradually.
Hardening Off Tomatoes
To avoid sun scald on your cherry tomato plants, always move them outdoors gradually. This process involves moving the plants into a sunny location for increasing amounts of time each day.
Learn how to harden off tomatoes here.
I recommend starting with around 20-30 minutes of direct sunlight, then moving the plants back indoors or into shade. If the plants begin to wilt or droop, get them out of the sun and wait until tomorrow to try again.
Tip: You can begin hardening off the plants before the last date of frost if the daytime temperatures are warm enough. Just bring them back indoors overnight.
After 3-4 weeks of steadily increasing sun exposure, the plants should be able to hand full sun.
Transplanting Into Full-Sized Pots
Once tomatoes are around 6-8 weeks old they will be outgrowing a 3″ pot. At this time, the plants should be moved into their final home.
For cherry tomatoes, use a pot that is at least 3 gallons, but ideally 5 gallons or larger for the best yields. Use the exact same method for transplanting into your large pots that you used before (see steps here).
In terms of tomato plant spacing, for potted plants you can keep each plant about 24″ from one another. This allows enough room for the plants to get good airflow through the foliage.
How Much Sun do Tomatoes Need?
Tomatoes are happiest when grown in full-sun conditions. This means 8-12 hours of sunlight daily. However, cherry tomatoes will still produce fruits in partial shade.
Find the sunniest spot available for your potted tomato plant. You can even move the plants throughout the day to follow the sun and avoid shade.
During the hottest parts of the year, you may wish to provide some shade for the plants, as they can become heat stressed. Watch for wilting leaves, curling leaves or sun scald and move to shade to reduce temperatures in the afternoon.
Setting up a Trellis or Cage
Depending on the type of cherry tomato you are growing, you may need to use a trellis or a cage. Cages are easiest, and are best used for determinate varieties. Simply place the cage into a large pot of soil, wedging the stakes around the perimeter of the pot.
For indeterminate varieties, you may wish to use a trellis. A cage will still work, but a trellis is ideal for training a single stem tomato plant to grow tall.
Potted plants can be trellised with a long, sturdy stake. Simply secure the stake in the soil, compressing firmly to ensure it does not fall over. I like these lightweight stakes from Home Depot.
With the plants successfully transitioned outdoors, all that is left to do is care for the plants by watering, pruning and fertilizing regularly.
Pruning Cherry Tomatoes
Whether you are growing determinate or indeterminate cherry tomatoes, some pruning will be required throughout the growing season. Left unpruned, tomatoes may be far less productive than is possible.
Indeterminate plants require the most pruning. Pluck away any of the sucker shoots that develop, leaving a single, central stem on each plant. The stem will continue to grow taller throughout the season, producing more and more flower trusses as it grows. You should also bottom prune any leafy branches that touch the soil.
Determinate plants should only be bottom-pruned, meaning that lower leafy branches should be snipped away. Bottom pruning keeps the leaves out of the soil, preventing pathogens from getting into the plant. Sucker shoots should be left on the plants to allow for increased yields.
Watering Potted Tomato Plants
Tomatoes drink a lot of water, especially when it is hot. Tomato plants in pots sometimes require daily watering, especially when grown in smaller containers. This is just another reason to grow them in the largest pot you have.
There are two easy methods I use to know when my plants need water. One is to lift the pot and feel it’s weight. You will get a sense for how heavy a watered plant feels vs one that is thirsty.
Another is to simply feel the soil’s surface. Dig 2-3 inches into the soil and feel for moisture. If it is dry, the plant could likely use a drink.
Always water tomatoes at the base of the plant, just around the stem. Avoid watering over the plant’s leaves. Thoroughly soak the pot with water, allowing all the excess water to drain away from the soil.
Harvesting Cherry Tomatoes
After a month or two, your tomato plants should begin to produce flowers. With enough friendly insect pollinators visiting your plants, those flowers will become fruits!
With any tomato variety, I recommend plucking the tomatoes as soon as they are ready. Never allow ripe tomatoes to sit on the plant – this can lead to cracking tomatoes and eventually rot or mold.
Learn more about harvesting tomatoes here.
Indeterminate plants will produce on an ongoing basis, so you’ll likely have a handful of tomatoes each day. Determinates will give you one big harvest, and then not much thereafter, so be ready to use your tomatoes when they come!
What to Do With Cherry Tomatoes
Once your plants have given you some ripe fruits, you may wonder what you can do with all of your bounty. I know how overwhelming it can be to get pounds of tomatoes in a single day, so here are a few ideas.
I hope this article helped you with growing cherry tomatoes in pots. I love growing all sorts of tomato types in containers, the reward is well worth the effort. Leave any questions or suggestions below, thanks!