Biting into a ripe, juicy tomato fresh from the garden is a sheer sensorial delight. Although tomatoes are warm-weather plants, they can be grown indoors throughout the year, where they will produce fruits through multiple seasons.
A tomato plant can live indoors for 2 to 5 years, where it is protected from frost. Tomatoes are not frost-tolerant and live for 6 to 8 months outside. However, you can keep your indoor plants alive for many years by controlling the temperature and providing them with adequate light.
It is not hard to grow tomato plants indoors and keep them alive and productive for several years. The key is to create the ideal growing conditions that mimic the light and temperatures found outside during summer. In this article, I will explain how you can keep tomato plants alive indoors and prolong the harvesting period.
How Do You Keep Tomato Plants Alive Indoors?
You can keep tomato plants alive indoors by providing them with natural or artificial light for at least eight hours daily. Tomato plants consistently need temperatures of at least 65° F (18.3° C) during the growing period. Water and fertilize regularly and keep pests at bay.
Here’s what you need to grow and keep your tomato plants alive indoors:
- Seed Starting Trays. It is not too hard to start seeds indoors. You must be mindful of providing the seeds with the right light and temperature conditions. You can also use egg cartons or plastic containers instead of seed starting trays.
- Sterile, Soilless Potting Mix. DO NOT use your garden soil because it can contain harmful pathogens that kill a young and tender tomato sapling. A clean, soilless potting mix is free of soil-borne pathogens and is light, fluffy, and well-draining.
- Heat Map. A heat map is not compulsory. It helps seeds germinate quicker in winter, but a sunny windowsill or the top of the refrigerator will suffice.
- Grow Light. Tomato is a warm-weather plant that needs 6-8 hours of sunlight to thrive. You must provide your indoor plants with ample warmth and light. You need to install grow lights that can keep temperatures at 75-80O F (23.9-26.7O C).
- A sunny spot in your home with southern exposure
- A Large Planter. Use an unglazed container to let the roots breathe. Ensure there are drainage holes at the bottom.
- Fertilizer or compost. Offering your tomato plants fertilizers and compost will ensure that it has all the nutrients it needs to grow healthily and quickly.
- Stakes. Stakes can support micro-dwarf varieties of tomatoes that do not grow more than a foot tall. You must use cages or trellises if your tomato plants grow to 10 feet (3.04 m).
Instead of growing from seeds, you can also grow tomato plants from seedlings you can buy at the garden center.
If you have tomato plants growing in your garden, you can snip a sucker or side shoot and root it in a glass of clean water or moist potting mix. If you are wondering, a sucker shoot is a vine growing between the main stem and a branch. It does not bear fruit if you leave it on the plant, so you can put it to good use and grow a plant from it.
Whether you grow tomatoes from seeds or buy seedlings, ensure that you learn about the variety. Some indeterminate varieties can grow more than 10 feet (3.04 m) tall.
If you don’t have space for large plants and the cages and trellises they need as they grow, you can buy seeds or seedlings of smaller varieties, such as Tiny Tim, Yellow Canary, Florida Petite, Red Robin, and Mohamed.
Below are the steps for growing and keeping tomato plants alive indoors:
1. Germinate the Seeds
Pour the soilless mix into the container where you will plant the seeds. Dampen the potting mix.
Sow the seeds about ¼ inches (0.63 cm) deep. Do not put more than three seeds in one hole of the seed starting tray or egg carton.
You can place the tray or the container on a heat map or on top of the refrigerator or radiator, where the seeds will receive warmth continuously. The seeds need temperatures between 65°F (18.3° C) and 85° F (29.4° C) to germinate.
You don’t have to provide light now. Just wait for the seeds to sprout.
The seeds will germinate within 1 to 2 weeks. Once they germinate, keep them under grow lights. You can also keep them on a sunny windowsill, but remember to give the container a quarter turn daily to prevent the seedlings from becoming leggy as they try to reach the light.
Tomato plants need at least eight hours of light to thrive.
2. Transplant the Seedlings
The seedlings will be ready for transplanting about a month after the seeds germinate. Transplant them to a larger pot, and use the same soilless potting mix to pack them in.
Ensure that you do not damage the tender roots of the seedlings when transplanting.
The seedlings might have fine hairy growth at the base of the stem. Plant the seedlings at this point because these fine hairs will become roots.
3. Provide Support for the Plants
Don’t wait for the plants to mature before staking them. If you try to drive in a stake when the plants are mature, you might damage the roots that have already spread.
You need to install a cage or a trellis for the indeterminate or vining varieties of tomatoes that can grow more than 10 feet (3.04 m) tall.
4. Water and Fertilize Regularly
Water the seedlings only when the soil feels dry to the touch. Poke your finger into the soil up to the first knuckle. If it feels dry, water the plant.
When growing tomatoes indoors, you have to do the work that wind and pollinators would have done had the plants been outside. Brush the flowers lightly to spread the pollen and speed up the fruiting process.
Fertilize the plants every two weeks and then weekly when small green tomatoes start to form. Feed every plant a quarter cup of an all-purpose fertilizer. Start feeding the plants with a high-potassium fertilizer when flowering starts.
Besides watering and fertilizing regularly, carry out the following tasks to keep your plants healthy and thriving:
- Turn the container 90 degrees daily to ensure every part of the plant receives sunlight.
- Turn on the grow lights on gray days.
- As the plants mature, transfer them to larger pots to give them space to grow.
- Do not prune determinate and micro-dwarf varieties of tomatoes.
- Prune the sucker shoots of indeterminate varieties.
5. Protect the Plants From Pests
Whether grown indoors or outdoors, tomato plants are vulnerable to pest attacks. Examine your plants minutely for signs of pest attacks. Do not forget to check the underside of the leaves.
Aphids and whiteflies are common tomato plant pests.
You can wipe the aphids off the plant or pick them up and kill them. You can also spray the affected areas with a solution of water and natural soap.
If these measures don’t eradicate the pests, prune the affected areas.
You can apply horticultural oil to get rid of whiteflies.
6. Harvest the Tomatoes Before They Ripen
It may sound counterintuitive, but harvesting the fruits before they ripen provides several benefits.
Harvesting tomatoes before they ripen reduces the chances of the fruit cracking. Insects are attracted to ripe fruits, so by picking the tomatoes early, you can keep away the bugs.
Harvest the tomatoes when they are ¾th ripe. At this stage, the top half of the fruit or the shoulder region is still green.
You can leave the fruits on the kitchen counter, and they will ripen within a few days. Ensure that the fruits are not touching one another when you lay them out on the counter.
How Long Will a Tomato Plant Produce Indoors?
A tomato plant will produce fruits indoors throughout the year if you provide it with the light, warmth, and water it needs. However, a determinate tomato variety will produce fruits once per harvest season.
You can prolong the harvesting season by sowing seeds every two weeks. If you have tomato plants growing outside, bring them indoors before the first frost strikes. You may not be able to keep the plant alive, but getting it indoors lets the fruits ripen.
Tomatoes have versatile uses in the kitchen. Although the plants die at the first instance of frost, it is encouraging to know that you can keep them alive indoors, where they will bear fruit.
Knowing how to grow tomatoes indoors lets you enjoy tomatoes in your favorite dishes throughout the year. Just keep in mind the following:
- Choose a variety that is conducive to growing indoors.
- Provide the plants with the warmth and light they need to thrive and fruit.
- Fertilize regularly.
- Protect the plants from pests.
- Harvest the fruits before they ripen.