How to Grow Tomatoes Indoors

Tomatoes are very popular and can be used in seasonal dishes all year long. But, unfortunately, they can't be grown outdoors all year long. Depending on where you live, the cold winter will kill off any tomato plants you have growing in your garden. Thankfully, you can grow tomato plants indoor all year round!

There are several techniques you can implement into your indoor gardening that will ensure yummy, juicy tomatoes all year long.

5 Minutes to Better Tomatoes

Free report shows how to increase your yield

Plant a Type of Tomato that Will Actually Grow

To grow tomato plants, you can just buy regular tomato seeds from the store. You can plant any tomato you want, though we have some really cool ideas for which ones to plant. Plant them 1/4 inch deep in six-inch deep pots. Keep the soil a little moist and put the pot in a warm location -- the top of the fridge is a good place. Start a new pot of seeds every two weeks for a constant supply of plants over the winter and also into the early spring months.

You will have the most success at growing indoor tomatoes if you choose varieties that are known for performing better indoors. Smaller, upright varieties are usually perfect. You can also purchase the hanging cultivars that will create arching plants. Here are a few things to keep in mind when shopping for seeds:

  • "Determinate" varieties will grow for a short period of time, and then all the tomatoes will ripen at once. After this, the plant can stop producing. These kind of seeds are easier to grow in a container because they don't require staking.
  • "Indeterminate" seeds continue to grow and produce fruit indefinitely and are much more likely to supply you with tomatoes throughout a long winter. However, they do require more care.
  • Plants that produce smaller tomatoes, like cherry or grape tomatoes, are almost always easier to grow and more productive than the larger "slicing" kinds of tomatoes.

5 Minutes to Better Tomatoes

FREE science-based report shows how to increase your tomato yield this season.

You Won't Eat If They Don't Get Light and Heat

The first issue is sunlight. Tomato plants need full sun and at least eight hours of light per day to produce any fruit. They also need warmth, so the indoor temperature should be 65 degrees Fahrenheit or more. It's a good idea to use unglazed pots that will breathe, with good drainage holes (and a pan underneath to catch excess water unless you want a mess). There are very small and portable greenhouse kits for use in a sunroom or other indoor environment that can help keep the plants contained and warm enough. 

If you want to have tomatoes literally all year long, it might be a good idea to grow your indoor tomatoes in successive batches. If you start new seeds every two weeks, you will always have tomatoes.

This winter-grown plant is taller than you...check it out (less than 2 minute video):

Once germination begins to occur every five to 10 days, you can move the pots to a brightly lit location, like on a windowsill or under a window. However, make sure the window isn't drafty and the interior temperature is still 65 degrees Fahrenheit or more. The most difficult part about growing tomatoes indoors is managing the temperature in your home.

In the winter, temperatures will still be very cool in your home, even if you have the heat on. Tomato plants are very sensitive and can still be affected by the slightest draft. Their growth can be stunted if they are in a cold climate, so be very careful with this. Flowering will be aided by warmer temperatures and the best growth occurs in temperatures from 75 to 85 degrees Fahrenheit. That's difficult (and expensive) to achieve during the winter, which is why it's a good idea to get an i´╗┐´╗┐nexpensive portable greenhouse to help you keep the plants warm. You can transplant the tomato plants into bigger pots when seedlings are at least three inches tall.

Turn your tomato plants frequently so that each side gets adequate sun, and both flower and fruit production is even. Stake the plant as needed to prevent the fruit from dragging and breaking the limbs of the plant. Indoor tomato plants will produce the same amount of fruit as outdoor tomato plants.

Don't Forget to Pollinate

Another problem with growing tomato plants indoors is the absence of pollinating insects. So, hand-pollinating is a good idea. All you have to do is tap the stems lightly when flowers bloom to spread the pollen. You can also use a Q-tip and put it into each flower to speed things up.

Fertilize Regularly - Plants Gotta Eat Too

It's easy to forget to fertilize plants, whether you're planting them outdoors or indoors. But, don't forget to do this, especially with tomato plants. If you're planting indoors, then the tomatoes will need all the nourishment they can get.

It's also important to choose a natural fertilizer. Harsh chemicals will be bad for you, the plants, and also the other people in your home. Harsh chemicals are also bad for pets, and can be life-threatening if consumed. Be careful with your choice of fertilizer, and keep it natural. Natural fertilizer might not make your tomatoes grow to a huge size, but they will help them to grow and will make them healthy for you. 

The fertilizer that I consider the gold standard for growing indoor tomatoes is called Tomato-tone. It's been around for a long time, it's organic, all-natural and university tested to produce big, plump tomatoes. It also comes in a bag size that is very manageable for indoor use.

As with growing any kind of plant indoors, you will probably have to experiment with location and lighting in order to get the best results. With time and care, you will be able to get those yummy tomatoes that you've been craving!

For a lot more great gardening tips, see our guide on 31 Ways to Make You an Organic Gardening Guru.

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