6 Easy Steps on How to Grow Tomatoes Indoors

how to grow tomatoes indoors

Tomatoes are a staple in most gardens. Because they are easy to grow and they produce so much fruit, gardeners love to have tomatoes in their backyard gardens. However, when winter hits, and you want fresh tomatoes, you will have to resort to an indoor growing space for them if you want to enjoy them in the off-season. If you’re wondering how to grow tomatoes indoors, you absolutely can do it, but it will take the proper equipment, time, patience, and learning.

Can You Grow Tomatoes Indoors?  

When the question “Can you grow tomatoes indoors?” comes up, it’s a yes…for the person who is willing to put some effort into getting the crop going. Just know in advance that it isn’t the easiest thing to do. Tomatoes love the sun and will be harder to grow without it.

Also, many tomato varieties can grow to be ten feet tall so growing them indoors is a stretch in most homes. That’s where learning about more appropriate varieties can help.

how to grow tomatoes indoors

How to Grow Tomatoes Indoors

1 | Sunlight

Tomato plants are big-time sun lovers and require a lot of light in order for them to thrive. This is why it can be so difficult to grow tomatoes indoors. They typically enjoy 6-8 hours of sunlight each day. If you have a south-facing window, this will be your best bet for getting your tomato plant enough sun. If you do not have direct access to the sun, then you should place them under grow lights instead.

OR Artificial Lighting

Tomatoes can do well under artificial lighting, as long as the proper steps are taken. Tomato plants will grow best under a full spectrum light, which means that all colors of the rainbow are used.

During flowering and fruiting stages, the tomato plant will do best under mostly red lighting.

2 | Soil

Tomatoes require rich and well-draining soil for optimal growth. If you plan on purchasing potting soil, then be sure to get one that is specifically made for tomatoes.

3 | Watering

Tomatoes require watering on a daily basis, but how often you water them depends on the type of pot that you use. If your pot does not have good drainage then it is best to soak the entire soil once before watering again. On the other hand, if your pots do contain proper drainage then only wetting around the surface of the soil until it begins to feel moist is necessary.

4 | Fertilizer

Tomatoes require a slow-release fertilizer that is rich in nitrogen and potassium. Potted tomatoes will require more fertilizer than an inground plant, so keep that in mind when you purchase and use your fertilizer.

5 | Air Temperature

Tomatoes do best when the temperature is between 75 and 85 degrees Fahrenheit. If the temperature in your home falls outside of this range, then it is important to use a heater or air conditioner to keep them warm.

6 | Pruning

Tomatoes need to be pruned in order for them to produce the most fruit. Pruning involves removing the suckers and leaves that are not necessary. The best time to do this is when the plant is young. Pruning isn’t necessary but can help your tomato plant produce more fruit.

Best Tomato Varieties to Grow Indoors

The best tomatoes to grow indoors are those that are meant for container growing. This includes micro dwarf tomatoes, which produce cherry-sized tomatoes.

If you have a large space like a greenhouse, you can try several varieties, but for a small space like a window sill, the best variety for growing tomatoes indoors is micro dwarf tomatoes. 

Micro dwarfs are extremely small tomato plants. They grow in 6” to one-gallon pots and are great for window sills.

If you are unable to find micro dwarf tomato seeds, you can also buy heirloom or dwarf tomatoes. They will do just as well in small spaces.

The Tiny Tim Tomato Seeds are a great selection for dwarf tomato seeds.

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Keep in mind that many dwarf and micro dwarf tomato plants are determinate varieties. This means they will produce their crop in a short flush in a couple of weeks’ time. Then they are finished producing.

To get a continuous indoor tomato crop, you’ll need to start growing new plants every couple of weeks.

Some of the most widely grown micro dwarfs are listed below…

  • Tiny Tim
  • Yellow Canary
  • Red Robin
  • Orange Hat
  • Tiny Totem
  • Tumbling Tom Hybrid – Great for hanging baskets
  • Micro Tom – world’s shortest tomato
  • Micro Tina
  • Micro Gemma
  • Vilma
  • Groovy Tunes
  • Gold Pearl
  • Fat Frog
  • Ink Spot – purple colored fruit with a sweet and tangy taste
  • Jochalos – tastes super sweet and delicious

How to Care for Indoor Tomato Plants

Hand Pollinating Tomato Plants

One very important thing to consider when thinking about how to grow tomatoes in your house is pollination. When we grow fruiting plants outdoors, there are bees and other insects to pollinate them for us.

But indoors, you’ll need to do this job yourself. It’s not that difficult to hand pollinate, but it is super important.

A study posted on the USDA website says that “one-third of all food and beverages are made possible by pollination, mainly by honey bees.”

Here’s how to hand pollinate:

Once the flowers open on your tomato plant, swipe the end of a q-tip around inside the flower to help move the pollen around.

Make sure that you gently q-tip the entirety of the flower, to include all parts. This way, pollen can be collected and transferred, just like in nature.

Think about how insects crawl around inside flowers with their legs coated in pollen, so that it gets spread all around the inside of the flower, and you’ll have a good idea of what you’re trying to accomplish.

You’ll need to hand pollinate daily.

In order to care for indoor tomato plants, you’ll need to provide a good growing medium, a nice environment with enough warmth, light, moisture, and drainage.

RECAP:

Medium: Choose a good potting mix (no soil is included in potting mixes) for your seedling and plant it in a pot with holes for drainage.

Warmth: You should maintain a temperature of at least 70 degrees in order for the tomato plants to be able to produce a decent amount of fruit.

Light:  Tomatoes want eight hours of sun, so place it in a sunny window or if you’re growing tomatoes indoors under grow lights, you’ll need to run the lights 16 hours a day. But be sure not to run them 24 hours, since they also need 8 hours of rest, just like humans.

Moisture: As far as watering goes, keep your plant’s soil moist but not soaking wet. Think about how a wrung out sponge feels and aim for that.

Drainage: Your pot must have holes for drainage. If the roots sit in standing water they will rot and kill the plant.

Growing Tomatoes Indoors on a Windowsill

Your best bet for growing tomatoes on a windowsill is to select a tiny tomato that can stay in a tiny pot.

An excellent choice for windowsill tomato growing is Micro Tom dwarf tomatoes, which take 75-85 days to mature from seed and only grow to about eight inches tall.

All the dwarf tomato plant needs is a 4-6 inch wide pot.

You’ll be surprised at the number of cherry-sized tomatoes this little plant will produce, and it will be fun to grow.

One last tip, turn the tomato plant often when they are near a window so that they get sun on all sides.

Growing Tomatoes Indoors in Pots

There are a lot of options when it comes to the actual container you use when growing tomatoes indoors in pots.

Here are a few of the options:

1 | Felt Growing Bags

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2 | 5-gallon Buckets

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3 | Clay Pots

4 | Plastic pots

5 | Ceramic pots

6 | Tin Cans

7 | Plastic Soda Bottles

Truly, anything can be used as long as the pot has adequate drainage. Most containers will need a saucer of some sort under them.

However, it’s different when growing hydroponically. That requires a closed vessel so the liquid, which is the growing medium, stays inside.

Growing Tomatoes Indoors Hydroponically

One way to grow tomatoes indoors in pots is to use a hydroponic method. Hydroponic growing sounds complicated, but one man found a way to make hydroponics simple and accessible for everyone. His name is Dr. B.A. Kratky from the University of Hawaii.

His basic growing method is super simple. There are no pumps, wicks, or special equipment needed, or even electricity.

The only items you need are water, mason jars with sleeves or black paint, hydroponic nutrient powder, rock wool cubes, net cups, and seeds.

1 First, you insert your seed into a cube of rock wool and allow it to sit in a shallow pool of water till it forms a seedling (or small plant) in a few days.

2 Once there’s a seedling, place the rock wool cube and plant into a small plastic pot with holes (net cup).

3 Put the neoprene sleeves on the mason jars (or paint them black).

4 Fill the mason jar with water and growing nutrients. Then place the cup in position, resting on the mouth of a mason jar. The very bottom of the net cup and rock wool cube sits in the nutrient water.

5 Over time, the nutrient water level will go down and will need to be refilled. When refilling the jar with the nutrient water, you must leave 2-3 inches of air in the jar so you don’t drown the plant.

So now the net cup and tomato plant will not be touching the water at all, but will rather be connected to the water through the dangling roots, which will hang right through the air gap and into the liquid.

Leaving an air gap between the base of the net cup and the top of the water allows air roots to form. Air roots are the way the plants breathe and are very important. They are the reason you do not need a pump to bring air into the jar.

Growing Tomatoes Indoors with Artificial Light

If you’ve been wondering whether you can grow tomatoes indoors with artificial light, the answer is yes. You do need to learn about artificial lighting, in order to effectively use it to replace sunshine.

One thing to know is that while tomatoes need 8-9 hours of sunlight each day, they will need 16 hours of artificial light each day. Then they’ll need to have the lights off for 8 hours each day.

There are a couple of ways to create an indoor lighting setup. You can purchase an indoor growing system designed to make everything easy and worry-free, or you can set up your own space with grow lights.

Indoor Growing Systems:

Indoor growing systems are created by brilliant designers, who have all or most of the kinks already worked out. They make growing indoors relatively easy.

Let’s take a look at the best indoor growing systems:

1 | For a small to medium countertop systems, the Aerogarden takes the cake.

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2 | For an upright and very aesthetically pleasing garden, the Lettuce Grow is a great choice.

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3 | The Tower Garden is another upright garden that is top of the line.

DIY With Grow Lights:

If you are looking for a cheaper option than a growing system, another possibility is to buy garage lights and large metal shelving units to house your plants on.

T-5 bulbs are the best ones for indoor tomato growing. Also, plants need light from the cool blue spectrum to grow their leaves, and from the warm red spectrum to grow their fruit, so you’ll want to alternate the two bulbs in your fixtures.

Light temperatures are measured by kelvins, so look at the bulb labels and choose one -6700k for the cool side and one -2700k for the warm side. 

If you don’t want to bother with figuring out the lighting, you can always grab these grow lights and call it a day!

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Try growing tomatoes indoors. I think you’ll have a blast, not to mention the tasty treats you’ll eat during the winter when no one else has them.

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