Tomatoes grown indoors can produce fresh and delicious tomatoes. Instead of consuming supermarket-bought tomatoes that are less tasty, you can enjoy fresh, hand-picked tomatoes. Growing tomatoes indoors is also very useful if you live in an apartment building where it is not possible to grow vegetables outdoors.
Step
Part 1 of 3: Sowing Tomato Seeds
Step 1. Choose tomato varieties that can grow well indoors
Indeterminate tomato varieties (continue to grow without stopping) are ideal for growing indoors. Unlike determinate tomatoes (short-growing like shrubs), indeterminate tomatoes continue to grow and produce fruit throughout the season. If you are looking for a tomato variety that produces lots of fruit and ripens quickly, choose indeterminate tomatoes with plum or cherry varieties.
- Pure indeterminate tomatoes (heirloom), including Pink Ping Pong, Silvery Fir Tree, Tommy Toe, Siberian, and Yellow Pear.
- Hybrid indeterminate tomatoes (crosses) include Micro Tom, Patio, Orange Pixie Tomato, Small Fry, Tiny Tim, Red Robin, and Totem.
- These tomato plants do not have thick branches and will naturally grow upwards so you must provide a tomato tree support cage (tomato cage), trellis, or stakes.
Step 2. Plant the tomato seeds into the planting medium
Wet the planting medium or potting soil with water until it is damp. Fill the nursery container with soil or a mixture of planting media. Make one hole in the planting medium in each box with a depth of about 1/2 cm. Insert about 8 seeds into each hole using your fingers or tweezers. Cover the hole with soil or a moist growing mix.
- Sow tomato seeds about 10 to 12 months before you want to harvest them.
- If you don't have a nursery container, just use plastic cups or drink cans.
- If you are using an old container, clean the container using a bleach solution made of 1 part bleach and 10 parts water.
Step 3. Accelerate seed germination with consistent application of heat and water
Germination is the process of transferring seeds into seeds. Tomato seeds take 5 to 10 days to germinate. You can do several things to speed up the process and ensure its success.
- After planting, immediately cover the tomato seeds with a plastic sheet or other cover. This is to prevent the soil from drying out.
- Move the nursery container to a warm place. During germination, keep the soil temperature between 21°C to 26°C. If your room cannot be adjusted to a minimum temperature of 21°C, try purchasing a heat mat or placing the container in a sunny location.
- Every day, open the lid and water the seeds as needed.
Step 4. Move the germinated seeds to a sunny or well-lit area
Tomato seeds and plants need between 12 and 15 hours of light a day. Without sufficient light, tomato plants will be weak. As soon as the seeds germinate, remove the cover and take the seeds to a place where there is light. If your window faces east (for regions in Indonesia), place the nursery right in front of the window. If your window is not facing east, use a fluorescent light to illuminate the seeds.
- The artificial light source should be located a few centimeters from the seed shoots. As the plant grows, you will need to adjust the height of the lamp.
- If you are placing the plant on a windowsill or in front of a window, rotate the container as often as possible so that each side of the plant gets sunlight.
Part 2 of 3: Transferring and Cultivating Seedlings
Step 1. Transfer the tomato seedlings to a large pot
Once the seedling has one or two pairs of leaves, the plant will not fit in the nursery container. When this happens, move the seedlings into pots that are large enough to accommodate the adult plants. The ideal container is one with a capacity of 20 to 40 liters.
- Remove the seedlings from the nursery container without damaging the roots. Pinch the seedling with two fingers and place your palms on the soil. Turn the nursery container upside down and gently tap the bottom of the container until the seeds emerge from the container.
- Loosen the roots by "picking" the roots that are on the outside.
- Plant the seeds until they reach the fine hairs at the base of the plant. These fine hairs will become the roots later.
- After transplanting, flush the seeds with abundant water.
Step 2. Water the plant if the soil is dry
Once the seedlings are transplanted, you should water them regularly. Check the condition of the soil every day whether it is dry or not by sticking your finger into the soil. Water the plant when the soil is dry. If the top layer of soil is dry but the bottom is still damp, water the plant another time.
Plants that grow in soil that is allowed to dry will produce tomatoes with a rough underside
Step 3. Provide lighting that mimics day and night conditions
While tomato plants need lots of light, they also need darkness. When you use a lamp as a light source, imitate the natural setting at sunrise and sunset. Turn on the light in the morning. After 12 to 16 hours have passed, turn off the lights and allow the plant to rest in the dark.
You can use a timer to adjust the lights
Step 4. Fertilize the seeds
Indeterminate tomato varieties will continue to grow and produce fruit every season. In order for this cycle to continue to run optimally, you must provide adequate nutrition to the plant. Within two weeks of transplanting, fertilize the plant for the first time. After this initial feeding, continue to fertilize your plant every few weeks until the plant is mature.
- Use a fertilizer that contains a lot of phosphorus.
- Follow the directions given on the packaging.
Part 3 of 3: Pollinating, Tree Formation and Harvesting
Step 1. Shape your plant so that it continues to grow
Indeterminate tomato varieties require a support from a stake or trellis as a vine. It's entirely possible for you to "shape" your tomato plant so that it grows into a trellis, stake, or tomato cage. You can start forming tomato plants about a month after the seedlings are transplanted.
- If you are using a dowel or a trellis with one wire, start forming the main stem. Tie the stems to the support with twine at every 15 to 20 cm. Use a loose knot so the stem doesn't hurt. If sucker shoots appear (shoots that appear between the main stem and branches), prune the shoots with your fingers to the base.
- If you're using a cage or trellis with lots of wire, start forming the main stem. Tie the main stem to the support with twine at every 15 to 20 cm. Allow the first 3 or 4 stem buds to grow on the stem. Form these stem shoots in the same way. Tie the stem shoots to a trellis or cage every 15 to 20 cm as they grow. Prune any new stem shoots that appear.
Step 2. Help the pollination process
If tomatoes are grown outdoors, the vibrations of the plant created by birds, bees, and the wind will spread pollen to produce fruit. If you are growing tomatoes indoors, you will need to simulate this process. You can do this by:
- Point the fan at the plant to mimic the movement of the wind.
- Gently tap or shake the main stem of each plant with your fingers.
- Pollinate plants by hand using a brush or cotton bud.
Step 3. Harvest your tomatoes
Indeterminate tomatoes produce fruit within 60 to 80 days after planting. This plant will continue to produce fruit throughout the season. Ripe tomatoes can be identified if the fruit turns bright and red, yellow, or pink. Tomatoes will be slightly tender when massaged.
To pick tomatoes, hold the fruit near the stem, then twist the tomato until it comes loose
Tips
- Try placing an adhesive bug trap near indoor tomato plants. If you are not careful, insects that usually attack ornamental plants, such as whiteflies, aphids, and spider mites (spider mites) can damage tomato plants.
- You can water and fertilize indoor tomatoes in the same way as outdoor plants. However, unlike outdoor soil, potting soil usually doesn't dry out easily.
