Comment cultiver et soigner les tomates en intérieur

De la plantation et

l’entretien des variétés anciennes

à la taille et

l’évitement des erreurs

, nous avons abordé de nombreux aspects de la culture des tomates (

Solanum lycopersicum

). Les pièges potentiels et les triomphes savoureux de la culture des tomates en font les aliments préférés du jardin tout au long de l’été. Mais que se passe-t-il lorsque vous voulez des tomates fraîches

pour votre soupe

en hiver ? Ou si vous n’avez pas accès à un espace extérieur pour vos conteneurs de tomates ?

Vous avez de la chance : transformez la saison de production de fruits par temps chaud en une aventure tout au long de l’année en remplaçant les tuteurs de tomates extérieurs par des jardins intérieurs. Bien que vous puissiez cultiver des tomates fraîches et savoureuses à l’intérieur tout au long de l’hiver, plusieurs conditions d’entretien doivent être respectées pour obtenir la meilleure récolte. Vos tomates d’intérieur ont toujours besoin de beaucoup de soleil et de chaleur, par exemple, et elles auront besoin de plus d’arrosage que les plantes grimpantes d’extérieur.

En tant que membre de la famille des morelles, les feuilles et les tiges des plants de tomates sont toxiques pour les personnes et les animaux domestiques, alors faites attention lorsque vous les cultivez à l’intérieur.

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Si vous manquez d’espace dans votre jardin ou si vous préférez cultiver des légumes à l’intérieur, où vous pouvez plus facilement contrôler les facteurs environnementaux comme la température et la lutte contre les parasites, lisez ce qui suit pour obtenir des conseils sur la culture des tomates à l’intérieur.

Attributs de la plante

Soins aux tomates

Pour que vos plants de tomates d’intérieur prospèrent, il est nécessaire de respecter des facteurs environnementaux spécifiques. Tout d’abord, ils ont besoin d’un bon éclairage, au moins six, et jusqu’à huit ou dix heures de lumière directe du soleil par jour. Ils auront également besoin de températures chaudes et humides, comme à l’extérieur.

Utilisez des plateaux de semis ou même une boîte à œufs vide remplie d’un mélange de plantation pour démarrer les plantes. Un terreau pour semis destiné à la plantation de légumes vous permettra d’éviter les problèmes fongiques et bactériens souvent associés à la terre végétale. Un système hydroponique, qui remplace la terre par un nutriment à base d’eau, peut également être une excellente stratégie pour cultiver des tomates à l’intérieur.

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Les systèmes d’arrosage automatique et les lampes LED intégrées peuvent faciliter les responsabilités des nouveaux jardiniers.

Si vous vous demandez quand démarrer les graines de tomates à l’intérieur (surtout si vous avez l’intention de les transplanter dans des jardins ou des conteneurs à l’extérieur), semez-les environ quatre à six semaines avant la date prévue de la dernière gelée de printemps dans votre région.

Lumière

Les tomates se développent en plein soleil

et ont besoin d’au moins six heures, voire plus, de lumière directe par jour. Lorsque vous cultivez des tomates en intérieur, vous devez placer votre plant de tomates dans une fenêtre ensoleillée pour qu’il ait de la chaleur ou investir dans une

lampe de culture LED

pour obtenir une source de lumière plus fiable.

Si vous utilisez une lampe de culture sans l’aide de la lumière naturelle, vous devrez placer vos tomates sous une lumière directe pendant environ 18 heures par jour (elles ont également besoin d’environ six heures d’obscurité). La lampe doit se trouver à une distance de 4 à 10 pouces du sommet de la plante, en fonction de la puissance et de la largeur du faisceau lumineux. En général, plus la puissance de l’ampoule est faible, plus la lampe doit être proche de la plante.

Sol

Use a pre-made soilless potting mix when growing tomatoes indoors. You can use a combination of vermiculite and peat moss and incorporate a 5-10-5 fertilizer with nitrogen, phosphorus, and potassium to add nutrients to the soil. Keep the soil moist but well-draining and slightly acidic with a pH between 5.8 and 6.8.

Water

Tomato plants growing indoors require more frequent watering than those grown outdoors. Use your hands to feel the soil to know when it’s

time to water

. Wait until the first inch or so is dry to water again. Keep the soil consistently moist, but well-drained. Provide plenty of air circulation and drainage holes—using a saucer under the tomato plant can help with drainage and prevent the roots from getting waterlogged.

Temperature And Humidity

Tomatoes love warm weather, so keep your plants in toasty temperatures—between 70° and 80° during the day. At night, temperatures can drop down to the mid-60s. Mimic sunny summer environments to help them thrive. Avoid placing plants near air vents. Shield them from cold drafts and excessive heat from furnace vents.

Keep tomatoes in an environment with slightly less humidity at night than during the day, which should be about 80 to 90 percent. In whichever room you plan to keep your tomato plants, you may want to invest in

a humidifier


and dehumidifier

to achieve these effects. Adding a mister or pebble tray of water can help, too.

Fertilizer

Once the plants begin to grow and emerge, you’ll need fertilizer.

Regular fertilization

helps tomato plants thrive since frequent watering depletes container plants of nutrients. You should fertilize the container of soil or potting mix before you add your tomato plant to prepare the environment. Then, use a weekly water-soluble or organic fertilizer for edible plants. Add a granular fertilizer every four to six weeks.

In general, tomatoes need a 10-10-10 fertilizer with nitrogen, phosphorus, and potassium. You should reduce how much nitrogen is in the fertilizer if you already have a good amount of it in the soil—too much nitrogen can cause abundant leafy green growth but not enough fruit. Many commercial fertilizers will also include calcium, which can help stave off blossom-end rot. You can also

use compost

as a fertilizer.

Types Of 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 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. Here are some popular smaller varieties:

• ‘Better Bush’: This variety bears medium-sized fruits on a compact plant. These tomatoes grow well upright and staked for support.
• ‘Candyland Red’: Candyland reds produce tiny, tasty, currant-type tomatoes, ideal for various foods.
• ‘Yellow Pear’: A heirloom tomato, yellow pears that bear large, bright, yellow, bite-sized, tangy fruits.
• ‘Roma’: This medium-sized variety looks like an elongated egg and does well in containers. It’s often used for canning after harvesting.
• ‘Tiny Tim’: A variety of cherry tomatoes, Tiny Tim plants only grow to about 12–18 inches tall, ideal for smaller spaces.

Pruning Tomatoes

Depending on the variety,

pruning tomato plants

is relatively simple. Determinate varieties need very little pruning. You must remove side shoots that grow off the main branch in indeterminate varieties,

like beefsteak

. The small stems do not produce fruit, so removing the excess stems will encourage the fruit-bearing branches to develop more than the foliage.

When pruning plants, cut dry plants early in the morning every few weeks. Continue to remove suckers as they emerge, using your fingers to pinch off suckers under 2 inches long. After staking the tomato plant, remove any excess foliage that touches the soil, as this makes the plant susceptible to infection.

Propagating Tomatoes

If your tomato plant is growing too big for its space or you want to grow more tomatoes, you can try propagation. Tomatoes can easily propagate using cuttings taken from seedlings. It’s best to do this earlier in the season. Here’s how:

1. Keep your tomatoes in a warm environment when making cuttings. Choose shoots with suckers on them that do not have buds.
2. Use sterile pruning shears to select a 6-to-8-inch selection.
3. Remove all leaves but the top set.
4. Place cuttings directly into clean water, or a container filled with damp soil, such as potting soil or vermiculite. Use your fingers or a pencil to create a hole a few inches deep in the soil.
5. Place the container with your cuttings in indirect light, gradually exposing it to light after around a week.
6. Cuttings growing in water should root in about a week but won’t be as strong as those growing in soil. Those growing in the soil should root in two weeks.

How To Grow Tomatoes From Seed

Tomatoes grow quickly from seeds, making them a

perfect garden plant

. Plant them six to eight weeks before you want to harvest. Here’s how:

1. Using a seed-starting tray, fill the container with damp potting soil and add two or three seeds in each section. Water deeply when sowing seeds.
2. Cover the entire container to preserve moisture. Place in a dark location, preferably around 70° to 80°.
3. Seeds will sprout within one to two weeks. After sprouting, move the container to a sunny location or use a grow light for artificial light.
4. Transplant seedlings after leaves appear. Ensure the new container has plenty of drainage holes.
5. Begin gradually exposing tomato plants to outdoor elements for a few hours daily. Prevent tomato plants from temperatures below 50°.
6. If preferred, transplant tomatoes to outdoor containers or a garden after two weeks of cold exposure. Add a layer of mulch around the roots if necessary to retain moisture.
7. Continue to water and fertilize tomato plants consistently. Prune branches that touch the ground to prevent diseases and remove fruit attacked by pests.

Potting And Repotting Tomatoes

Tomato plants prefer to keep their roots intact once established, so try to select containers large enough to accommodate the plant’s growth. If necessary, to repot plants, carefully dig around the root system and place the plant in the new container so a portion of the stem is below the soil line. Gently pack the soil around the base of the stem and water deeply when transferring. Fertilizing the plant at the time of planting can help add nutrients to the plant it may have lost during repotting.

Overwintering

Tomatoes growing indoors still need plenty of light during the winter season. While it is possible to grow these plants throughout the colder season, pay close attention to the water and fertilizer schedule so the depleted nutrients do not impact the plant’s growth. Using a grow light can help provide artificial light for the tomato plants growing indoors, but avoid placing the container near a furnace or heat vent.

Common Pests & Plant Diseases

Growing tomato plants indoors does not mean pests and diseases will not impact them. Aphids, whiteflies, spider mites, and

common pests

can infest the plant but are treatable if caught early. Spraying plants with water is often the most effective method of removing pests, but if the issue persists, there are ways to trap or handpick pests. If these methods are not solving the problem, consider using neem oil.

Some diseases that impact tomato plants growing indoors include rot, wilt, and blight from waterlogged roots. Maintaining proper care will help prevent these diseases from developing, including providing plenty of direct sunlight, drainage holes, and the correct amount of fertilizer.

Common Problems With Tomato Plants

Indoor tomatoes face many of the same problems as outdoor plants. While tomatoes need specific environmental ideals to thrive indoors, there’s usually an apparent fix for what ails them if your plant isn’t thriving indoors. For example, many of the issues facing tomatoes,

like cracking

, involve inconsistent watering, which is easily remedied. Keep an eye on things to ensure they get the care they need.

Curling Leaves

If your leaves start to wither and curl, this could be due to high temperatures, overwatering, and aggressive pruning. Check on the light and water they’re receiving. Adding fertilizer or amending the soil can also help.

No Fruit

Your tomato plant should flower a few weeks before it begins to fruit. 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. Adjust your system so your plant is getting the elements it needs

Leaves Turning Yellow

Tomato plants need many nutrients to thrive, especially container plants growing indoors. As indoor plants require more frequent watering, the soil nutrients often deplete faster than plants grown in an outdoor garden. To ensure healthy tomato plants and avoid

yellowing leaves

, use a fertilizer with iron, magnesium, and nitrogen. Yellowing leaves are also a sign of older plants, but if you are beginning your tomato plant’s growth, the lack of nutrients is probably the reason for the foliage discoloration.

Blossom-End Rot

If your plant isn’t getting enough calcium either in the soil or during watering, then it can develop

blossom-end rot

. This is when the end of the tomato opposite the stem develops black spots that are rotting. Remove these tomatoes, add a nitrate fertilizer to the soil, and water regularly.

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