Can you grow tomatoes all year in a greenhouse?


commercial greenhouse of tomatoes

Tomatoes are picky plants that require full sun and heat to develop and fruit. These conditions are not ideal with the changing seasons. However, with a proper greenhouse, you can plant your favorite fruit any time around the year. This is because you can control the conditions of the greenhouse to favor the plant.

Tomatoes grown in a greenhouse are protected from the elements, such as cold and rain, which can cause fungal infections. Growing tomatoes in a greenhouse all year demands a lot of attention and money. All conditions, including pollination, must be managed.

This article will offer you insight into effectively growing tomatoes in your greenhouse during the different seasons.

Factors necessary for growing tomatoes in a greenhouse

Temperatures

For effective growth and productivity, the temperatures in the greenhouse need to be 70-80 F. (21-27 C.) during the day and night temperatures of 60-65 F. (15-18 C.).

Therefore, this will require cooling during the day or warming at night, depending on your climatic region and season.

Air circulation

The plant also requires effective air circulations, which are provided by proper spacing and exhaust fans. This factor is essential for the internal environment as it also helps keep the humidity levels constant. Fluctuating levels of humidity can favor the growth of fungus, bacteria, and viruses and destroy plants.

Spacing

As we just saw above, spacing is essential for the adequate circulation of air. Additionally, with proper spacing, light can reach all the plant leaves.

It would be best to plant tomatoes in paired rows 28-30 inches (71-76 cm.) apart. Also, the space from one pair to the next should be 36 inches (91 cm.)

Avoid crowding your tomato plants and ensure a distance of at least 24 inches or 61 cm between plants. If you plant them any closer, they will be competing for resources such as nutrients and water. This competition will lead to weak plants with light green leaves and low yields.

Watering

Tomatoes require well-drained soils to thrive. For this reason, as you water your plants, avoid getting the ground too wet.

Drip irrigation is an excellent watering choice as it ensures moderate and consistent eater supply directly to the plant roots.

Also, as you water, the plants aim at keeping the moisture content at levels under 90%. Moisture levels above this encourage the growth of molds which destroy the plants. This also goes hand in hand with the proper ventilation that we covered above.

To ensure these levels of moisture, avoid watering the plants unit the soil is dry. This also helps the gardener understand the amount of water your plants require. You can water the plants every day depending on how fast the water dries up.

Misting the plants is also helpful as it helps distribute the water evenly. At the same time, it helps with the problem of overwatering your plants. Additionally, it prevents soil from splashing on the tomato plant leaves. Always remember that wetting the tomato leaves and fruit attracts diseases.

The best watering time for your greenhouse tomatoes is in the morning. You should, however, avoid watering the plants two to three hours before sunset.

Too much water is harmful to the plants as it disrupts the supply of air under the soil, causing the root to rot. On the other hand, if you don’t supply enough water to your plants, they will wilt, flowers and fruit might drop, and the yield goes down.

Staking

Staking tomatoes is critical as it prevents the weak stems from collapsing. It also helps prevent the leaves and fruit from contact with soil and moisture, which causes infections, pest attacks, and rotting.

The process mainly involves supporting the plant and is best done during planting. Remember staking at later stages could harm the plant roots. As the plant grows, you should then tie its stalk to the support. The best practice involves tieing each half-foot of the plant.

Lighting

Plants need light to manufacture food. The light available during certain seasons of the year might not be adequate for tomato plants. This is one of the reasons people grow tomatoes in greenhouses during winter.

For this reason, if you are growing your tomatoes during winter, you need supplemental lighting throughout the season.

An excellent source of lighting for tomatoes in a gree house is the use of high-pressure sodium lights, which encourage flowering and fruiting.

Also, you need to use these lights between 16 to 18 hours a day for the best results. The light you use should also be of the recommended wattage for the area.

It would help if you also considered growing light as tomatoes require a lot of sunlight to grow. This kind of light is most appropriate during winter as it also helps increase the temperatures around the plants.

Location

Before you place your tomatoes in a greenhouse, first ensure that it is healthy. For this reason, you need to treat any diseases and pests you feel could threaten the health of the plants before growing them there.

The practice of crop rotation is essential in taking of these problems. Avoid planting tomatoes in the same spot every season. It encourages the growth of tomato virus, fungus, pests, and bacteria.

Plant companionship is also helpful. In this case, you need to plant your tomatoes close to plants that deter specific pests and diseases. Some excellent choices for tomato companionship include lavender and basil. The two plants will help deter whiteflies that commonly spread diseases and pests among tomato plants.

If you want more tips on growing tomatoes check out the video below where I take you through how to get mind-blowing results.

Choice of tomato variety

The tomato variety you choose should be suitable for the greenhouse. As you purchase, research the different types of tomatoes and choose a greenhouse breed that suits your needs.

Generally, there are two types of tomatoes: determinate and indeterminate.

The determinate variety has more compact bushes and takes up less space. Additionally, they do better in large pots and require more frequent watering.

Another distinctive feature of these tomatoes is that they produce tiny fruits that ripen all at once, after which the plant dies.

Indeterminate tomato plants are more extensive and taller. They also require support to stay up. You will, therefore, need to provide staking or cages for the tomatoes.

Indeterminate tomatoes are also tastier and bigger. These tomatoes also require larger spacing to flouring and give a good yield. Additionally, they reproduce for longer.

Since indeterminate tomatoes are more extended, if you have a smaller space or smaller greenhouse, you might want to consider some smaller types called miniature or dwarf tomatoes.

Here are some excellent tomato choices for greenhouses: sweet million, gardeners delight, Cappricia, and Sungold. for potting, you can go for the sweet million variety.

These are no the only tomato varieties you can grow in greenhouses. Some outdoor tomatoes also do well in a greenhouse. If unsure, you can always seek help from specialists. You can also read the packaging and see if the tomato is suited for greenhouse farming. Greenhouse varieties are always indicated.

It is important to note that it will fail if a tomato variety is not suited to greenhouse conditions.

Soil Preparation

Tomatoes require well-fertilized soil to flourish. The use of compost provides an endless supply of nutrients to your plants. As you add the compost, remember that this is a greenhouse, and there will be rainfall.

The use of too much compost could destroy the plant roots. For this reason, find a balance by using the compost in moderation. Additionally, you can neutralize the maure by adding hay or leaves.

Ensure to mix in the compost with the existing soil effectively. This helps in spreading the manure evenly through the ground. Additionally, you also break the particles of the soil and manure. This is necessary for the growth of the plant roots.

Next, you need to dig the hole and add fertilizer. The best fertilizer choice for tomato plants is that with high levels of phosphorous. Other essential nutrients for tomatoes include magnesium, nitrogen, calcium, and potassium. Nevertheless, you should test the soil before adding the fertilizer.

Controlling Pests and diseases

tomatoes with blight

Tomatoes are prone to attacks by pests and diseases. Some common pests in tomatoes include whiteflies, aphids, nematodes, flat beetles, and cutworms. The most threatening of these pests are whiteflies and aphids.

Here are some measures to control pests:

Aphids

You need to get rid of infected leaves and take them away from the greenhouse to prevent the spread. Alternatively, you can use natural control methods such as the use of ladybugs. These insects will help keep your plants healthy by feeding on aphids and other pests. Also, it would help if you acted as soon as you noticed the pests’ signs because they spread fast. I wrote an article on how to get rid of aphids. You can read it here.

Cutworms

To prevent cutworms from attacking your plants, put cardboard cones around the seedlings.

Flea beetles

To contain this pest, you need to place sticky traps. As for the young plants, you can cover them.

Nematodes

Plant rotation is an effective solution to the problem, and you might need to sterilize the soil in areas with severe infections.

Whiteflies

These pests can be controlled through sticky traps. Another solution is the use of ladybugs. Always remember that pesticides are not good for edible plants and should come as a last resort. I wrote an article on how to get rid of whiteflies. You can read it here.

Damping-off

This is a tomato disease caused by viruses. The disease often affects young and fragile tomato plants. It leads to a black wound close to the soil line, after which the plant dies. It occurs from overwatering, overcrowding, and low temperatures. To prevent the virus, make sure the soil you use for potting is fresh and clean. You should also avoid frequent or overwatering your plants, especially within the first two weeks after germination.

Fusarium wilt

This is a common soil-borne fungus infection that affects tomatoes and other vegetables. It is only detected when the fruit starts to mature. The plant side leaves turn yellowish at this time, and when sliced, the stalk will appear brownish. To prevent the fungus, you can practice crop rotation with plants that do not support the virus. You should also avoid watering the leaves, more so in cold weather.

General ways of controlling pests and diseases:

  • Plucking weeds
  • Remove infected leaves to prevent the spread
  • Use of good fertilizers
  • Planting tobacco plants close by. However, if you are a smoker, always wash your hands before touching the plants.
  • Ensure the greenhouse is well ventilated, more so in summer
  • Avoid overwatering the soil and keep it just moist. Damp soil promotes damping-off disease and other problems such as mold.
  • Avoid using overhead irrigation as wetting the leaves of tomato plants can expose the plant to diseases.
  • Prune falling leaves to allow sunlight to reach all the plant leaves and prevent fungus-like grey molds.

Conclusion

If you seek to grow tomatoes all year round, then a greenhouse will make a perfect solution. Crop maintenance in a greenhouse is also costly. For this reason, you need to do thorough research to do it right and cut down on losses.

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Tony O'Neill

I am Tony O'Neill, A full-time firefighter, and professional gardener. I have spent most of my life gardening. From the age of 7 until the present day at 46. My goal is to use my love and knowledge of gardening to support you and to simplify the gardening process so you are more productive

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