Skip to main content

How to grow tomatoes indoors during the fall

As the growing season comes to an end, you may still experience the urge to grow juicy tomatoes in your garden. Growing tomatoes in the fall isn’t a mere pipe dream—you can definitely plant tomatoes indoors come autumn when it gets too cold outside. While keeping your plants healthy may be a challenge initially, it’s not an impossible endeavor. Ahead, we go through how to grow tomatoes indoors, breaking down all the tips and tricks you need up your sleeve when it comes to getting a successful harvest.

Orange tomatoes on a vine
Andrea Riezzo / Unsplash

How to pick tomatoes to grow indoors

When you’re picking out tomatoes to grow indoors, it’s best to go with smaller varieties. You’ll come across two different types of tomatoes: determinate (bush) and indeterminate (vine). Indeterminate tomatoes will more likely produce fruit throughout the season, but they may require more support and surface area. If you’re keen on finding a plant that’s more space efficient, a determinate one may be the way to grow. Indeterminate varieties include Tommy Toe, Red Robin, and Tiny Tim, among others. Determinate ones include Washington Cherry, Cherries Jubilee, and Gold Nugget.

How to start tomatoes indoors

Getting seedlings or more mature plants will be the easiest route for growing tomatoes, but these may not always be readily available as seeds, especially outside of the growing season. While grabbing seeds from a garden center will be easiest, you can even take some from tomatoes you might already have lying around the house!

Starting seeds is relatively straightforward. You can soak your seeds for a day to help better their chances of germinating, but this step isn’t always necessary. While biodegradable seed-starting pots can be helpful, you can also situate your seeds inside containers you have at home and cover them with coco coir or some other sterile seed-starting mix. (Remember to poke in some holes for drainage!) As long as you give your seeds bright light in addition to warmth and moist soil, they should germinate in five to ten days.

When your seedlings are three to four inches tall, it’s time to transplant them into a planter, preferably one that’s clay for water absorption and at least 12 inches deep for roots to grow. When potting your tomato plant, use a well-draining potting mix—garden soil will be too heavy for a container-bound plant.

Person holding tomatoes on plant
Image used with permission by copyright holder

How to care for tomatoes indoors

  • Watering and feeding: Whenever you water your tomatoes, make sure you water your soil all the way through. You’ll know that it’s time to water when the top inch of the soil feels dry to the touch. Since tomatoes are heavy feeders, mix an organic slow-release fertilizer into the potting mix.
  • Lighting: Tomato plants need at least eight hours of bright light a day. If your home doesn’t get that much light, supplement natural lighting with grow lights. With artificial lighting, situate your lamps no more than a handful of inches above your tomato plants. If you keep your lights too high, your plant may become leggy as it tries to stretch towards the light source. Side note: While you might not be able to get as much light inside, the advantage to growing tomatoes indoors during the autumn is that it’s warmer inside—tomatoes need temperatures of at least 65 degrees to flourish.
  • Supporting: Even indoors, tomato plants, especially the vining variety, may need extra support as they grow, or else they might flop over. Install a small trellis, stake, or cage to keep your plant upright.
  • Pollinating: One of the biggest challenges when tending tomatoes indoors is that you don’t have pollinators or wind to help distribute the pollen so fruit can grow. However, you can definitely work your way around this hurdle. One way is to use a fan to create a soft breeze. You can also gently shake your tomato stems to help distribute the pollen. And last but not least, you can use a cotton swab to spread the pollen around.
Cupped hands holding ripe and unripe cherry tomatoes
Image used with permission by copyright holder

How to know when it’s time to harvest your indoor tomatoes

Tomatoes develop fruit sometime between 60 and 80 days after you first start them. Ideally, tomatoes should be picked when they’re still slightly greenish. Even after you pluck them, tomatoes will continue to ripen off the vine and turn redder in color. The advantage is that if you pick them before they’re completely ripe, you won’t risk as much bruising. After harvesting tomatoes from an indeterminate variety, you can continue to care for your plant so that it keeps producing fruit.

While the thought of growing tomatoes indoors may seem like a daunting endeavor, it’s actually a feasible undertaking. By tending after tomatoes inside, you can keep a close eye on their growth and protect them from the elements come cold, wintry weather. After two to three months of hard work, you’ll be able to reap the literal fruits of your labor!

Editors' Recommendations

Stacey Nguyen
Stacey's work has appeared on sites such as POPSUGAR, HelloGiggles, Buzzfeed, The Balance, TripSavvy, and more. When she's…
Here’s how you can help indoor ferns thrive
From lighting to fertilizing, here's how to care for an indoor fern
Bird's nest fern growing in a white pot

Ferns are beautiful. They can add a touch of elegance to the shade, whimsy to the shadow, and softness to the dark and damp. Can they do the same for the shady corners of your house, though, or are they limited to just your outdoor garden? This is what you need to know to keep your indoor ferns flourishing.

Basic fern care
Ferns, in general, are fairly low maintenance compared to other plants. They really only need a few things, most of which are pretty simple and make a lot of sense when you consider their natural habitat.

Read more
A guide to growing rosemary indoors from seed to spice up your dishes
Tips for a delicious rosemary harvest
Potted rosemary plants on a table

Many herbs can grow indoors under the right conditions. Rosemary belongs to this lot. The easiest way to do it is to purchase existing seedlings and repot them at home, leaving them with room to grow. Because of that, many people don’t readily know how to grow rosemary from seed — at least indoors and in a way that will help the plant thrive.

Some of the most important questions to keep in mind when growing rosemary indoors from seed are: What kind of soil does rosemary like? How do I care for my indoor rosemary? By answering those queries, we’ll help you grow successful rosemary plants.

Read more
How to grow mint indoors with these 3 different methods
Whether you grow your mint from a full plant or cuttings, here's how to keep it healthy
Mint on windowsill

Mint is a phenomenal herb, useful for entrees, desserts, drinks, and even some home remedies. If you’re looking to add mint to your indoor kitchen garden, you may be wondering about the different methods you can use, and which one is right for you. Well, look no further! Let us show you how to grow mint indoors, and let us give you all the answers to all your minty fresh questions!

Basic mint care
Mint is a sturdy, hardy plant, and it is remarkably easy to care for. It is so hardy, in fact, that it has a habit of escaping gardens and growing where it shouldn’t! So, a primary part of mint care is keeping it in check and not allowing it to spread. However, this isn’t an issue for indoor mint unless you plan on using it in a combination planter (that is to say, planting it with other plants). In that case, you should usually be fine, but keep an eye on it to make sure it isn’t overtaking the other plants.

Read more