Greenhouse Gardening - How to Grow Tomatoes?

Greenhouse Gardening - How to Grow Tomatoes?

March 14, 2017

 A tomato is a gardeners' cream of the crop. If you had tomatoes from a garden before, you cannot deny that store-bought ones cannot keep up with those from a garden. If you love them as much as we do, you may be wondering how to grow tomatoes in a greenhouse.

Tomato is a popular greenhouse crop that provides an excellent harvest. The tropical and humid condition of your greenhouse is ideal for planting tomatoes. With good lighting and proper temperature control in your greenhouse kit, you can easily have multiple harvests yearly. Note that proper handling of these greenhouse conditions facilitates two of the most important processes: successful pollination and disease prevention.

Is it a fruit or a vegetable?

The tomato is one of the top five most consumed fruits. Or vegetables? You might be wondering as well what could it be. Did you know that the U.S. Supreme Court ordained in 1893 that tomatoes are vegetables notwithstanding the botanical evidence that they are carefully considered as fruits?

However, according to the United States Department of Agriculture, tomatoes are considered fruits while nutritionists and the horticulture trade consider them as vegetables. The word “fruit” is used to represent sugary and fleshy while "vegetable" means that it doesn't have a very high fructose level. However, botanically speaking, a tomato is unquestionably a fruit. So technically a tomato is the fruit of a tomato plant, and it is used as a vegetable in culinary perspectives.

Choose the type of tomatoes you want to grow in your greenhouse

There are diverse varieties of tomatoes. They have its individual unique grown fruit, taste and culinary purpose. Let’s have a look at these:

Cherry tomatoes

Cherry tomatoes are the smallest and sweetest variety. They are ideal for salads and pasta recipes.

Planted Green and Red Cherry Tomatoes

Plum tomatoes

Plum tomatoes are fleshy usually have fewer seeds and excellent for appetizers, soups or sun-dried. They are larger than cherry tomatoes and have an oblong shape.

Beefsteak tomatoes

Beefsteak tomatoes are the heaviest weighing even more than 200g. These tomatoes have a lean texture which is perfect for grilling, packing and they are often used on sandwiches.

Cordon or indeterminate tomatoes

Indeterminate plants develop extensively and soaring above until you finally stop them. Their fruit is carried on the shoots coming off the chief stalk. Harvest extends over a sustained duration. Conveniently plant them in raised beds, grow bags, or transplant them into the garden when the soil temperature moves at least 55°F. Support them with tall stakes. This variety is the most popular and is developed as single stemmed plants with eliminated side shoots.

Bush or determinate tomatoes

Determinate plants develop reasonably compact bushes with smaller main stalks and they are just perfect for smaller spaces. This variety stops growing earlier than cordon. They are also called as a dwarf variety which is advisable in hanging baskets. They do not expect pruning.

Their fruit ripens all at the same time. They are best raised in huge pots, containers, raised beds, and grow bags. Use containers that can hold five gallons or more. The pots require sufficient drainage holes. Apply fresh potting soil that flows thoroughly. Stake them in advance. Container plants expect constant watering. Never prune side shoots, because these are your tomato's fruiting shoots.

Semi-determinate tomatoes

Semi indeterminate varieties are like bush tomatoes. They are grown as determinate but they just bear smaller plants.

How to set up your greenhouse for your tomatoes

The first step involves checking the temperature, selecting the right tomato variety, choosing a medium to grow the crop, and installing the recommended irrigation system.

  • Tomato plants provide better yields if day temperatures range from 70°F to 80°F and night temperatures from 60°F to 65°F respectively. This accurate warmth inside helps you grow tomatoes in a greenhouse with higher expected yields.
  • When selecting a variety, choose seeds that are marked as 'greenhouse varieties’ since these are tolerant of the conditions inside a greenhouse. Choose the letters VFNT and A after the name indicate that the type is resistant to diseases. If you are doubtful about what seeds to buy, then it may be wise to talk to local growers. Their wealth of information will easily lead you in the right direction.
  • Generally, tomatoes thrive in a well-draining medium such as a soilless medium, Rockwool slabs or perlite bags, vermiculite and sphagnum peat moss mixed in the ratio 1:1.
  • It is recommended to use a drip irrigation system because it provides a steady supply of water directly to the root system and you can also use it to automate the fertilizer application.
  • Keep moisture under 90% to prevent leaf mold. Regular ventilation brings fresh and dry air particularly when it is cold.

How to grow tomatoes in a greenhouse

  • You may use a soilless tray and seed nutrient solution. RSI Hydroponic Floating Seeding Trays will give you a high success rate of transplanting your tomatoes.
  • Get the tray ready by making it moist using water or nutrient solution. Water is appropriate for moisturizing soil while the nutrient solution is meant for a soilless tray.
  • Plain water is advisable until the mixture is quite wet enough to squeeze into a mass, with just a few drops when compressed.
  • Ensure you expose the trays to ample lighting. These grow lights will provide your seedlings all the light they require to thrive even in winter.
  • Dig a quarter of an inch hole inside every cell of your seeding tray. Shoot a single seed inside each hole. Coat carefully with your potting mix. Plant around 10 to 15% extra seeds that you intend on growing, so you can ditch the least vigorous seedlings.
  • The seeds normally sprout in one or two weeks.

Tomato seedlings planted in a healthy soil

  • Transplant them into small pots and then again into bigger pots when they attain a height between four to six inches. These raised beds can give your tomatoes the sufficient space they need.
  • Regularly apply nitrogen and potassium-rich fertilizer.
  • Remove offshoots weekly. Do not leave a piece behind that may die after.
  • It is best to use trellises or stakes for them to climb straight and spread out.
  • You may also need to use a mechanical pollinator on the tomato plants to help pollinate the flowers and prune the leaves when the plants begin to fruit. Check out more about the VegiBee Garden Rechargeable Pollinator here!
  • Guard them against the freezing temperature and intense winds which may destroy them.
  • Remember that even bigger species may bear less fruit if planted in smaller containers. Starting them near each other can reduce air circulation and promote disease.
  • Ensure that the calcium and pH levels are appropriate in the greenhouse before this last transplantation.
  • If the soil is acidic, you can combine about one teaspoon of hydrated lime per gallon of potting mixture.

You can choose to plant tomatoes in the greenhouse border for them to have a sufficient place to climb, get enough sunlight, and for them to get enough water most of the time. There will be lesser chances of getting diseases but they may not have enough water. So make sure to address this concern when planting in pots and bags.

Recommended Tomato Greenhouse: Arcus

Save your time and energy from moving your tomatoes in and out of the greenhouse just to get sufficient air and sunlight. With the Arcus, you can plant and raise them directly inside your greenhouse. Bees and other beneficial insects can visit and pollinate your plants anytime you want by opening the sidewalls.

3 Tier Arcus greenhouse with plants inside

Introducing the absolute ventilating greenhouse with no additional ventilation system needed. All you need to do is slide up the walls and feel the cool breeze. Polycarbonate walls offer stability, insulation, and UV-protection. Install it on almost all ground types. Enjoy the summer and feel secure in wintertime. Get more information about the Arcus Greenhouses here!

Pests and disease control

  • Remember to regularly ventilate your greenhouse in summer to deter pests and diseases.
  • Replace the soil before growing another batch of tomatoes to prevent pests and root diseases.
  • Maintain a moist soil but be mindful not to over-water since damp soil may promote damping-off disease and additional mold problems.
  • Do not install an overhead irrigation system because the leaves of tomato plants are susceptible to diseases.
  • Pruning the falling leaves to allow more sunlight to prevent grey mold fungus.

Those thick bunches of tiny aphids can be on the stems or brand new leaves of your tomatoes. It is not really a big deal if it is just a small number. Don’t be discouraged to mash them using your thumb because extensive infestations can deliberately damage or even destroy your crop. Take off the leaves where aphids are clustered, and throw these cut portions into the garbage bin and not on the soil. If it still persists, use the insecticidal detergent that uses organic materials.

Damping off is caused by some viruses. This disease is a tomato dilemma that concerns fragile, obviously healthful seedlings that quickly form a dark wound at the soil line, and suddenly wilt and rot. Cool, wet soil, overcrowding and overwatering can cause this contamination. Make sure to use clean potting soil, seed trays, and accessories to lessen the rate, prevent packed seedbeds, and control watering thoroughly throughout the first two weeks after germinating.

Fusarium wilt is caused by a soil borne fungus that aims tomatoes, potatoes, peppers, and eggplant. It usually creates no indications until the plants are ripened and green fruit starts to attain its grown size. At that time leaves on the side of your plant becomes yellow, and a sliced stalk will reveal brownish, smeared tissue. Crop rotation helps so the wilt parasites will lose its host and will die eventually in the affected ground where it lives. Cool and soggy situations favor this disease. Never spray water on leaves, particularly in cold weather.

Water your tomatoes properly

For a bountiful crop, make sure to water them regularly. Tomatoes are always craving for water. You can use tap water or rainwater from water butts.

Planted tomatoes that just got watered

Harvesting your tomatoes

The longer your tomatoes stay on its vine, the fuller and redder they mature. You can harvest anytime depending on how full and red you want them to be. Do not put them on a sunny spot to ripen because they may decompose even before they ripen. The best time of day to pick tomatoes is early in the morning.

How to properly store tomatoes

Tomatoes don’t freeze well so it is better eaten straight after picking. It ripens fast so don’t let it stay in your kitchen for more than a week. If you have too many tomatoes at once, you could preserve them.

If you are ready to start growing purchase your tomato seeds here.


Let us know your experience of planting and growing your own tomatoes. Leave us a comment below!

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