Growing Tomatoes In Winter

Growing tomatoes in winter is often laughable unless you have a greenhouse, owing to the plant’s need for over 8 hours of sunlight daily. However, you do not need to make such a substantial investment just to enjoy freshly picked, flavorful tomatoes deep in the middle of the winter season. With a  few tomato cages, you can transform a few square feet of your indoor space into an indoor tomato growing space.

While tomatoes cannot survive outdoors during winter or cold weather, they will grow well indoors if you provide the optimal conditions. Let’s dive into how you can grow tomatoes in winter.

Can Tomatoes Grow In Winter?

Yes, tomatoes can grow in winter, but they require more care and attention than in summer. The biggest challenge is providing the plants with enough sunlight. Tomatoes need at least 6-8 hours of sunlight per day, and in the winter, the days are shorter, and the sun is less intense.

You can grow tomatoes in a greenhouse during winter as a greenhouse will trap the sun's heat and provide the plants with the sunlight they need, even in the winter. However, greenhouses can be expensive to build and maintain.

The next alternative is to grow tomatoes indoors under grow lights specially designed to give plants the light they need to grow and produce fruit. Remember that there are many grow light varieties in the market, so choose ones appropriate for tomatoes.

Can You Grow Tomatoes Outdoors During Winter?

Depending on the climate in your area, you can grow tomatoes outside if it does not get too cold or if you can harvest the fruits right before frost sets in. Tomatoes are not frost-tolerant, so they must be protected from freezing temperatures. If you live in an icy climate, you must grow your tomatoes in a raised bed or container. This will help to insulate the roots and protect them from the cold.

Why Grow Tomatoes in Winter?

Growing tomatoes in winter presents several advantages, primarily related to maintaining a fresh supply of this versatile fruit during the colder months. Tomatoes are a staple in many cuisines and offer many culinary possibilities. Here are the reasons why one might opt to grow tomatoes during the winter:

     1. Freshness and Quality

Growing tomatoes indoors during winter ensures a steady supply of fresh, high-quality tomatoes. Store-bought options may lack the same level of freshness and taste.

      2. Year-Round Availability

Cultivating tomatoes in winter allows you to enjoy this essential ingredient year-round, breaking free from seasonal limitations and ensuring a continuous supply for your culinary needs.

     3. Controlled Environment

Indoors or in a greenhouse, you can carefully control the growing conditions, including temperature, humidity, and light. This control ensures optimal growth and can lead to better yields and higher-quality produce.

     4. Extended Growing Season

Growing tomatoes in winter extends the typical growing season. By starting the plants early and providing the right conditions, you can enjoy tomatoes much earlier than outdoor-grown varieties in the spring.

     5. Personal Satisfaction

Gardening can be a rewarding and therapeutic hobby. Growing tomatoes in winter allows you to engage in this enjoyable activity throughout the year, contributing to your sense of accomplishment and well-being.

     6. Experimentation and Varieties

Winter gardening allows you to experiment with different tomato varieties that might not thrive in local outdoor conditions. This expands your horizons in terms of flavors, colors, and textures.

     7. Cost-Efficiency

While initial costs are associated with setting up an indoor or greenhouse system, growing your tomatoes can be cost-effective over time compared to consistently purchasing them from stores.

     8. Reduced Environmental Impact

Growing your tomatoes sustainably and organically reduces the environmental impact of commercial farming, such as transportation and packaging.

Challenges and solutions of growing tomatoes in winter

Sunlight and temperature

The biggest challenge of growing tomatoes in winter is providing enough sunlight. Tomatoes need at least 6-8 hours of sunlight per day, and in the winter, the days are shorter, and the sun is less intense.

If you are growing tomatoes indoors, you must provide them with supplemental lighting. Grow lights are specially designed to provide plants with the light they need to grow and produce fruit.

Another challenge is protecting the plants from frost. Tomatoes are not frost-tolerant, so they must be protected from freezing temperatures. You can do this by covering them with a row cover or cloche at night. Remember that tomatoes fruit between 50-95°F (10-35ºC), so you must have a thermometer nearby to keep track of the temperatures indoors.

Pests and diseases

Tomatoes are susceptible to various pests and diseases, which can be more challenging to control in the winter when the plants are indoors. Inspect your plants regularly for pests and diseases. If you find any pests or diseases, treat them immediately. If your area is prone to pests, you should consider getting a tomato cage with a pest barrier netting.

Pollination

Tomatoes need to be pollinated to produce fruit, an activity that’s otherwise carried out by the bees outdoors when the weather is warm enough for them to fly around and collect nectar and pollen. If you are growing tomatoes indoors, you may need to hand-pollinate them. To do this, gently brush the pollen from the male flowers onto the female flowers.

Watering and applying fertilizer

Tomatoes need to be watered regularly, but you have to be careful not to overwater them, which can lead to root rot. Fertilize your tomato plants every few weeks with a balanced fertilizer.

How to Grow Tomatoes In Winter

1.      Choose a determinate variety.

These varieties have a predetermined height and tend to stop growing once they reach a specific size. They are suitable for limited space and tend to produce fruit earlier, making them ideal for a winter growing season.

Opt for varieties with a relatively short "days to maturity" period. In the context of winter growing, quicker maturation allows you to harvest sooner and enjoy fresh tomatoes earlier in the season.

Here are some compact tomato varieties that produce fruit relatively quickly:

• Cherry tomatoes
• Early Girl tomatoes
• Patio tomatoes
• Tumbling Tom tomatoes
• Celebrity tomatoes
• Siberia tomatoes

2.      Start the tomato seeds indoors.

Starting tomato seeds indoors ensures a successful winter tomato-growing venture. It allows you to control the early stages of growth and provides a head start before transplanting the seedlings into your indoor garden or greenhouse.

Start by gathering all the supplies you need to set up a seedbed indoors. These include:

• Tomato seeds of your chosen variety
• Seed-starting trays or pots with drainage holes
• Sterile seed starting mix
• Grow lights or a sunny windowsill
• Watering can or spray bottle
• Plastic dome or clear plastic wrap

Next, you should mix the sterile seed starting mix with water until it is uniformly damp but not waterlogged, and use it to feel the seed starting trays or pots, leaving a little space at the top to avoid water overflow later on.

Plant the tomato seeds according to the recommended depth for your chosen variety. Typically, it's about 1/4 to 1/2 inch deep. Space the seeds adequately to allow room for growth. Remember to Label each tray or pot with the tomato variety and planting date. Cover the trays or pots with a plastic dome or clear plastic wrap to create a greenhouse-like environment that retains moisture and warmth.

3.      Provide the right conditions for germination.

Tomato seeds germinate best when the soil temperature is between 75-90°F. Any lower germination will be delayed. Use a heat mat or grow lights to maintain the proper temperature. The soil should be kept uniformly moist but not soaked for successful germination. The top layer can be allowed to dry out between waterings slightly. However, don't let the seeds dry out completely.

Once the seeds have germinated, remove the plastic wrap or humidity dome. Place the seedlings under grow lights if necessary. Tomatoes need at least 6-8 hours of sunlight per day.

4.      Transplant the seedlings

Once the seedlings have developed true leaves and are large enough to handle (usually when they are about 6 inches tall), transplant them into larger containers or individual pots. Take care not to disturb the roots.

5.      Provide adequate light

The indoor light might not be enough for a growing tomato plant, so you must get a grow light. When choosing a grow light for tomatoes, selecting one that produces the right spectrum of light is essential. Tomatoes need a full spectrum of light, including red and blue light. Red light is vital for flowering and fruiting, while blue light is critical for vegetative growth. LED lights are the most popular choice for indoor tomato growers because they are energy-efficient and produce a full spectrum of light.

6.      Watering the tomato plants

Tomatoes must be watered regularly, but be careful not to overwater them. Overwatering can lead to root rot and other problems.

The best way to water tomatoes is to water them deeply and infrequently. Water the plants until water runs out of the drainage holes in the bottom of the container. Allow the soil to dry out slightly between waterings.

You can check the soil moisture by sticking your finger into the soil up to the first knuckle. If the soil is moist, there is no need to water. If the soil is dry, it is time to water.

7.      Fertilizing indoor tomato plants

Tomatoes are heavy feeders, so they need a high nitrogen, phosphorus, and potassium fertilizer. You can use a balanced fertilizer that is specifically designed for tomatoes. Fertilize the plants every 2-3 weeks. Be careful not to over-fertilize your tomatoes. Over-fertilizing can lead to foliage burn and other problems.

8.      Hand-pollinating tomato plants

Hand-pollinating tomato plants is a simple process that can help to ensure a good fruit set. It is especially important to hand-pollinate tomato plants if you are growing them indoors, as there may not be any pollinators present.

You can also hand-pollinate tomato plants by shaking the plants gently. This will help to dislodge the pollen from the male flowering parts and onto the female flowering parts. Hand pollination is best conducted in the morning when the flowers are open and should be handled delicately to avoid damaging the flowers.

Overwintering Tomatoes Indoors

Overwintering tomato plants indoors is a great way to extend your growing season and enjoy fresh tomatoes all year. It is also an excellent way to save money on seeds or seedlings, as you can overwinter your plants and replant them next year.

To overwinter tomato plants indoors, follow these steps:

1. Choose healthy plants that are still producing fruit.
2. Cut back the plants by half.
3. Remove any diseased or damaged leaves.
4. Dig up the plants and carefully remove the root ball.
5. Transplant the plants into individual pots.
6. Place the pots in a bright location indoors.
7. Water the plants regularly, but be careful not to overwater them.
8. Fertilize the plants every few weeks with a balanced fertilizer.
9. Prune the plants regularly to remove any dead or diseased leaves.

Tips On How To Grow Healthy Tomatoes Indoors

Tomatoes prefer temperatures between 65 and 80 degrees Fahrenheit. They also prefer humidity levels between 50 and 70 percent. If the temperature or humidity is too high or too low, it can affect the growth and production of the plants.

Tomatoes are susceptible to a variety of pests and diseases. Inspect the plants regularly for pests and diseases. If you find any pests or diseases, treat them immediately.

Mulching is the application of a layer of material to the surface of the soil around plants. Mulching can be done indoors or outdoors, and it has several benefits, including:

• Retaining moisture in the soil
• Suppressing weeds
• Moderating soil temperature
• Improving soil structure
• Adding nutrients to the soil

Selecting a lightweight and well-draining material is essential when choosing a mulch for indoor tomatoes. You should also avoid using materials that contain chemicals or herbicides. There are a variety of materials that can be used for mulching indoor tomatoes, including:

• Straw
• Compost
• Peat moss
• Bark chips
• Coco coir
• Perlite
• Vermiculite

Tomatoes are ripe when they are red and firm. To harvest a tomato, cut it off with a sharp knife or garden pruning shears.

Conclusion

With some care and attention, you can grow healthy and productive tomato plants indoors, even during winter. Following these steps and providing appropriate care and attention to your seedlings will set a strong foundation for growing healthy and productive tomato plants indoors during winter. If you are looking for tomato cages, hydroponic containers, pH sensors, and other indoor growing supplies, check out our collection.

Written December 2023
By Susan Grey