Here’s how to plant tomatoes in a greenhouse

Tomatoes need warmth and are sensitive to rain - so they produce the greatest yields in greenhouses. We show you here how to lay the foundations for a good harvest when planting seedlings.

Apr 09, 2021 02:26 pm
readtime icon 6 Minutes
Tomatoes

A film covering with good ventilation provides tomatoes with the perfect climate and is the best protection against the dreaded brown rot

What would the summer be without home-grown tomatoes? The number of delicious varieties is larger than for any other type of vegetable: red, yellow, striped, round or oval, cherry-sized or nearly weighing a pound. It’s best to choose a variety according to the intended purpose. Seedless, elongated Roma tomatoes are particularly delicious in pasta sauces, thick, fleshy tomatoes are used for grilling, plum-shaped mini tomatoes are best enjoyed as a snacking vegetable between meals. Tiny wild tomatoes are an eye-catcher on any vegetable platter, and yellow or orange-colored cocktail and cherry tomatoes look highly appetizing next to fresh, green herbs.

Plant in greenhouses from mid-April

The earliest planting period in the greenhouse is mid-April. Loosen the earth as deeply as possible beforehand and then work in compost. Depending on pre-cultivation and soil condition, 0.53 to 0.79 gallons per 10.76 square feet is enough. Where fungal diseases are problematic, for example in regions with heavy new potato cultivation, follow up by pouring stinging nettle liquid manure or dusting rock flour and marine algae over the soil. A tomato house is recommended even in warmer locations. Even a simple, self-built film cover provides enough protection against the wind and rain, making the plants less susceptible to the dreaded brown rot.

Tomato house
A tomato house is even recommended in warmer locations. Even a simple, home-made film cover provides sufficient protection against the wind and rain

There is no guarantee; in years with high infestation rates, an infection cannot be avoided even in a closed greenhouse. However, the disease generally progresses much more slowly in a greenhouse. An infection occurs if the leaves are dripping wet for more than several hours. First aid measures: Cut off and dispose of the lower leaves up to 15.79 inches above the soil. You can prevent any other diseases by regularly changing the plant bed. Although this is often not possible in smaller gardens or in the greenhouse. Tip: In this case, plant varieties such as ‘Hamlet’ or ‘Flavance’ that have the necessary resistance against soil fungus and root pests.

Guiding tomatoes upwards on cords

Stake tomatoes require a stable scaffold. Spiral metal rods at least 5.91 feet tall which plants can be easily guided up clockwise are particularly practical. On the other hand, cultivation on cords has proven itself successful in greenhouses or under film covers. These are simply secured to the roof struts and the stem base of the respective plant. Then simply wind the growing central shoot around the cord bit by bit.

Step-by-step: The correct way to plant tomatoes
Positioning the plants
Photo:MSG/Folkert Siemens
Positioning the plants
Positioning the plants
Photo:MSG/Folkert Siemens
01
Positioning the plants

The young plants are initially positioned with generous distances, including the pot.

Digging out the planting hole
Photo:MSG/Folkert Siemens
Digging out a planting hole for tomatoes
Digging out the planting hole
Photo:MSG/Folkert Siemens
02
Digging out a planting hole for tomatoes

Leave 23.62 to 27.56 inches in the row, and at least 31.5 inches space between rows. The ground should be loosened deeply and any weeds removed beforehand. Then simply rake in 1.32 gallons of mature compost per 10.76 square feet. You can dig out the first planting hole with a hand shovel. It should be about the depth of the pot ball plus 1.97 inches.

Remove cotyledons
Photo:MSG/Folkert Siemens
Remove cotyledons
Remove cotyledons
Photo:MSG/Folkert Siemens
03
Remove cotyledons

Pinch off the tomato cotyledons with your fingernails before planting. These will die anyway and are potential gateways for fungal diseases.

Removing the earth ball
Photo:MSG/Folkert Siemens
Unpotting tomatoes
Removing the earth ball
Photo:MSG/Folkert Siemens
04
Unpotting tomatoes

Now it’s time to unpot the tomatoes. If the soil is very dry, you should firstly submerge the balls including the pots in a water bucket once again.

Setting the tomatoes
Photo:MSG/Folkert Siemens
Planting the tomatoes
Setting the tomatoes
Photo:MSG/Folkert Siemens
05
Planting the tomatoes

The tomatoes should be planted deeply enough that the lower 1.97 inches of the stem are covered with soil. This has two advantages: The plants will stand more securely and form additional roots above the ball.

Push down the soil
Photo:MSG/Folkert Siemens
Push down the soil
Push down the soil
Photo:MSG/Folkert Siemens
06
Push down the soil

Carefully push down the plant bed soil down around the stem with finger tips.

Watering saplings
Photo:MSG/Folkert Siemens
Watering saplings
Watering saplings
Photo:MSG/Folkert Siemens
07
Watering saplings

Water each sapling thoroughly and ensure that the foliage does not get wet. You should also label the varieties with stick labels.

Attaching a cord
Photo:MSG/Folkert Siemens
Attaching a cord
Attaching a cord
Photo:MSG/Folkert Siemens
08
Attaching a cord

The tomatoes need to be supported to prevent them from falling over under the weight of the tomatoes. Cultivation on a cord is a proven method under a film cover: Fix a sufficient length of new, plastic cord over each tomato plant to a strut of your film cover or greenhouse roof.

Tie the cord to the stem
Photo:MSG/Folkert Siemens
Tie the cord to the stem
Tie the cord to the stem
Photo:MSG/Folkert Siemens
09
Tie the cord to the stem

The other end of the cord is laid around the stem and carefully knotted in a loose loop close to the soil. Wind the new growth around the cord about once a week to provide it with support.

Finished saplings
Photo:MSG/Folkert Siemens
Finished saplings
Finished saplings
Photo:MSG/Folkert Siemens
10
Finished saplings

Now all the freshly planted tomato saplings have to do is grow.