How To Grow Tomatoes Indoors

Keep your indoor tomato plants thriving with these top tips.  

We've covered lots of ground when it comes to growing tomatoes. From planting and tending heirloom varieties to pruning and avoiding mistakes, we've learned a lot about the potential pitfalls and eventual tasty triumphs of tomato growing. Those lessons usually happen outdoors, where our tomatoes grow staked in the sun.

However, we've been learning the benefits of growing tomatoes indoors. If you're currently without garden space or prefer to grow veggies indoors where you can more easily control environmental factors like temperature and pest control, read on for some tips on starting tomatoes indoors.

Cherry Tomatoes
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Meeting specific environmental factors is necessary to keep your indoor tomato plants thriving. First, they need good lighting, at least six and up to eight or ten hours of direct sunlight daily. You'll want to place your tomato plant in a sunny window for warmth, or you can invest in an LED grow lamp for a more reliable light source. Tomatoes love warm weather, so keeping your plants in toasty temperatures (70 degrees or higher) mimic sunny summer environments and will help them thrive.

Seeds, Soil, and Water

To start the plants, use seed trays or even an empty egg carton filled with planting mix. A seed-starting potting mix geared toward vegetable planting is more likely to help you avoid the fungal and bacterial issues often associated with topsoils. A hydroponic system can also be an excellent strategy for growing tomatoes indoors. Self-watering systems and built-in LED lamps can help ease responsibilities for new gardeners.

Once the plants begin to grow and emerge, you'll need fertilizer, plant stakes or a miniature trellis, and bigger pots or planters with drainage features to keep the roots from becoming soggy.

If you're wondering when to start tomato seeds indoors (and if you intend eventually to transplant them into gardens or containers outdoors), then sow them about four to six weeks before the anticipated date of your area's last spring frost.

Choosing Your Tomatoes

Your first instinct may be to find the tastiest tomatoes imaginable, but there are a few more things to consider when choosing which tomatoes to grow. For an indoor plant, your best bet will be to choose a compact variety that produces small fruits, like a cherry tomato or grape tomato. Hanging cultivars can also be suitable for small spaces. You can buy a starter kit, which will set you up for success, or you can find seeds at your local garden store.

Popular smaller varieties include Better Bush, Candyland Red, Celano, Early Wonder, Fantastico, Firefly, Jelly Bean, Matt's Wild Cherry, Midnight Snack, Patio Choice Yellow, Red Choice, Red Rocket, Red Torch, Terenzo, Tiny Tim, Toy Boy, Tumbling Tom, Valentine, and Yellow Pear.

Common Issues

If your tomatoes aren't thriving indoors, check on the light and water they're receiving. Adding fertilizer or amending the soil can also help. If flowers appear on your tomato plants but no fruits are developing, this could result from nighttime temperatures that are too low or too little water. If your leaves start to wither and curl, this could be due to high temperatures, overwatering, and aggressive pruning. While tomatoes need specific environmental ideals to thrive indoors, there's usually an apparent fix for what ails them. Keep an eye on things to ensure they get the care they need.

Enjoy Your Harvest

Get your tomatoes started, give them attention and plenty of light, and you'll enjoy the fruits of your labor. Once you've had your first harvest, try including your new tomatoes in a recipe.

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