Tomatoes originally come from sunny South America. Accordingly, their claim for healthy thriving lies in warm temperatures. This limits the time for planting out. The following will reveal when the best time to plant tomatoes is outdoors, on the balcony and in greenhouses and what else to look out for when planting out.
If the tomato plant has spent the winter in a warm house or was cultivated there, it is necessary to slowly acclimate it to the colder outside temperatures before planting it out. The procedure is as follows:
- Start hardening/habituation about two to three weeks before planting out
- Place the plant in sunshine for two hours during the day in an open window (avoid drafts and direct sunlight)
- Alternatively, a sheltered location on the balcony can be chosen
- It can only be exposed outdoors by the hour for the acclimatization phase from the end of May (half-shady place).
- Slowly and evenly increase the duration of the fresh air supply
- About two weeks are enough for hardening
Tip: Hardening can be accelerated by putting a translucent film with air holes over it (avoid contact between the film and the leaves)
Best planting time for tomatoes in the greenhouse
If you own a greenhouse, you can look forward to an early date for planting. The ideal planting time for tomatoes here is mid to late April. The prerequisite is that the plants in question have been grown indoors at temperatures between 18 degrees Celsius and 24 degrees Celsius.
As a rule, greenhouses offer protection against frosty temperatures, even when unheated, so that the tomatoes are not damaged after planting. But the winters are getting colder and longer in Central Europe. Freezing temperatures in April could be possible. To ensure that planting out at this point does not pose a threat to the tomatoes, it is advisable to use natural heat as a precaution.
Mist for frost-free greenhouse
Manure, and horse manure in particular, provides a natural source of heat for tomatoes and ensures that unheated greenhouses remain frost-free even when outside temperatures are freezing. This is due to the fact that the (horse) manure develops heat during the decomposition phase and distributes it in the environment. In this way, hobby gardeners and self-sufficient save the costs of purchasing a plant heater and energy costs for operation.
A functioning “manure heater” in greenhouses is created as follows:
- Before planting the tomatoes, dig out the soil about 70 centimeters deep
- Lay out the manure in it and press firmly
- Compost is then laid out at a height of between 20 and 30 centimetres
- Finally, enough substrate is filled in so that the plant can be planted optimally
Best time to plant tomatoes outdoors
Wait until after the ice saints in mid-May before planting them out in the vegetable patch. Then there is no more ground frost to be expected, which can damage the plants immensely.
But cold winds can also occur in May, especially at night, and damage tomato plants that are sensitive to cold. Those who live in harsh areas should stretch a fleece or translucent film over them overnight. A foil tunnel has proven to be a very effective protection against the cold. Unexpectedly cold night temperatures are usually no longer to be expected by mid-June at the latest and the fleece or film can be removed. It is important that the leaves do not touch the foil.
Instructions fleece and foil tunnel
- Cut bendable tubing, such as electrical conduit, to a length that will reach over the plants and be clear of the plant height
- Three meter long pipes can be used to tunnel over two rows of tomatoes that are 75 centimeters wide next to each other
- Stick about 25 centimeters firmly into the ground on one side
- Bend over the plants and stick firmly into the ground on the other side
- Rohrab stand: about 1.5 meters
- Place foil with air holes or fleece over the arches
- Overlap the film/fleece generously in the front and rear areas so that the tunnel can be completely closed
- Use a sandbag or something similar to weigh down the film/fleece at each end of the arch as well as in the front and back
- At warmer temperatures, the film is raised to allow air exchange
- If the outside temperatures remain constantly higher, the tunnel can be dismantled (usually at the end of May)
Best planting time for tomatoes on the balcony
Normally, the planting of tomatoes on balconies as well as outdoors can begin from mid-May after the ice saints. However, depending on the weather, it is advisable to wait a little longer until the end of May/beginning of June. Planted in window boxes, pots or tubs, they require special attention when it comes to cold. The plants feel this much more strongly because the roots are not protected by a thick layer of soil, as is the case in the vegetable patch. Only a thin outer wall of the container and a little substrate separate colder temperatures from the roots.
If you still want to plant tomatoes on the balcony in mid-May, you should definitely use a so-called tomato hood. This consists of a weatherproof foil, which has air holes so that an exchange of oxygen can take place. In addition, spacers should be placed in the planter to keep the tomato cap away from the leaves.
Best conditions for planting out
The weather is not crucial for healthy, vigorous growth of tomatoes, although it is an important criterion. But other conditions also play a role in determining the best time to plant tomatoes. These include:
- Temperatures constantly above 13 degrees Celsius
- The plant has a height between 30 centimeters and 40 centimeters (is therefore more robust than small young plants)
- First umbels of flowers can be seen (plant is growing and roots can better establish themselves in the ground)
- Hardening should ideally be carried out for at least ten days, preferably 14 days
- Plant must not be dead