The extension of the growing season, protection against temperature and weather changes, and safe growing environment are the answers to why do tomatoes grow better in polytunnels. These three advantages make the polytunnel an ideal environment for growing tomatoes compared to the traditional style of field growing. However, you need to understand how each benefit works to connect with the factors to consider when growing polytunnel tomatoes.
3 Advantages Of Growing Tomatoes In Greenhouses
Greenhouse growing of tomatoes presents three advantages over field growing: extension of the growing season, protection against temperature and weather changes, and a safe growing environment. Polytunnel tomato farming has been rising since the mid-1990s. The explanation behind this is the increasing preference of customers to the quality of tomatoes raised under these three advantages.
If you think about it, protection against temperature, weather changes, and a safe growing environment will consistently yield quality tomatoes. You’re eliminating the variable conditions that can cause the tomatoes to be of a low standard. As a result, the demand for polytunnel tomatoes will be consistent as well.
Extension of the growing season
Tomatoes can be picky plants, so it’s typical for field growers to have a shorter growing season depending on their UK region. Using a polytunnel eliminates this drawback because you don’t have to stop growing your tomatoes once the summer months are over. Growing tomatoes in the polytunnel give you the advantage of extending your harvest season up until late autumn.
If you’re using a polytunnel for growing tomatoes, you are not limited with your growing and harvest season, even though your UK region has a short duration of summer months. This also allows you to get a second crop or even start sowing your tomatoes much earlier. If you think about it, this leaves you fewer possibilities for production problems regardless of the season.
Protection against temperature and weather changes
The consistent and controllable temperature and weather conditions inside the polytunnel favours the growth and production of high-quality tomatoes. Let us paint you a picture of a rainy day that lasts until the night. What will happen to your crops?
The open exposure of tomatoes in the rain will drench their leaves. And in some cases where the season is colder, the combination of wet leaves and a drop in temperature will undoubtedly be detrimental to your plants’ health. But how bad can it be, right?
For starters, the tomatoes will have a more challenging time absorbing nutrients. This makes them more vulnerable to diseases and other conditions. Therefore, growing tomatoes indoors will protect the plants from the inconsistencies of temperature and weather outside.
Now, you might be thinking, “but what if the polytunnel also limits my tomatoes from sunlight?” A polytunnel can be beneficial whether your tomato varieties thrive in warm or cool conditions. The structure retains the sun’s radiation for consistent heat, but you’ll also be protecting astonishing variants from harsh sunlight.
Safe growing environment
Besides the consistent and controllable temperature and weather, the polytunnel makes a safe growing environment ideal for tomatoes. Its structure will make it impossible for predators like birds, rodents, and large mammals to access the plants. The enclosed environment will also deter anyone from causing potential damages to your crops.
Raising tomatoes in an enclosed structure like the polytunnel can even be beneficial for you in another way. Keeping them indoors will also contain helpful insects such as ladybugs and praying mantids. In turn, the presence of these insects will help you keep troublesome pests at bay.
How Do You Grow Tomatoes In A Polytunnel Year-Round
You can grow tomatoes in a polytunnel year-round if you consider the tomato variety, season, location, temperature, feeding, and watering beforehand. It’s not enough that you have the directions on how to plant tomatoes in a greenhouse. That part is easy, but to growing them correctly, there are some significant considerations beforehand.
Using a polytunnel extends the growing season of tomatoes. However, failing to execute a plan according to these factors will give you a hard time achieving a year-round production. Let us take a look at how each element plays a role in growing polytunnel tomatoes year-round.
Tomato variety
Similar to when you’re growing tomatoes outdoors, you have to be knowledgeable in what varieties would be suitable in an indoor environment. It doesn’t sound effortless, but it’s as simple as choosing the seeds marked as polytunnel variants. They are so-called because they built to tolerate the conditions indoors instead of your usual UK garden varieties.
What are the polytunnel tomato varieties
For greenhouses, you want vine or cordon tomatoes. In particular, the most popular and widely-used tomato variety in the United Kingdom is called Trust. This is a Beefsteak-type tomato, and it makes an excellent polytunnel variant.
There are also Dutch hybrids called Match, Switch, and Blitz that are all worthy considerations for indoor growing. On the other hand, Marnero and Marhold are similar to Cherokee Purple and Striped Germans, respectively, if you want heirloom-like variants. These polytunnel tomato varieties are indeterminate, which means they can grow several meters long and produce over a long harvest season.
Once you’ve selected an indoor variety, you can also consider types that are resistant to diseases. Over the years, breeders and companies have created varieties that are less prone to diseases and disorders. A quick tip for finding these variants is to look for the letters V, F, N, T, and A after their names.
Season
The most significant advantage of growing polytunnel tomatoes is that it’s possible to grow them year-round. Depending on the location, you can have up to two tomato crops during the year as long as you maintain the conditions inside the greenhouse. This is in comparison to the limited growing season in field tomatoes, where frost is a concern.
Since you want to grow your tomatoes in the polytunnel year-round, you need to plan on how you can plant on a two-crop rotation. Growing tomatoes in a field meant planting the seeds before the last frost of the year. But with polytunnel tomatoes, you can seed an autumn crop and a spring crop in early June and December, respectively.
Can you grow tomatoes in a polytunnel in winter
Yes, you can grow tomatoes in a polytunnel in winter because greenhouses can trap the heat from the sun’s radiation and keep it inside. However, be aware that the heat inside is only relative to how cold it is outside. Therefore, the heat retained by the polytunnel may not always be enough for growing tomatoes during winter.
To ensure your tomatoes are getting sufficient heat in the winter, you have to provide auxiliary heat in the greenhouse. It would help if you also considered adding the costs of supplemental lighting every winter to make up for the insufficient natural light in this season. Therefore, you can still experience an increase in yield on your polytunnel tomatoes in the winter as long as you provide sufficient heat and light.
Location
The location you choose also affects the year-round success of growing tomatoes in a greenhouse. You have two options on where you can grow polytunnel tomatoes: in the polytunnel borders and pots. Both have advantages and disadvantages, so the final decision depends on you.
Greenhouse borders
Growing tomatoes in a polytunnel border makes it possible for you to avoid water deficiency and magnesium problems. This is because the border stores water well, and the large volume of soil in it prevents fertiliser overdose. However, it can be tedious for some to prepare and maintain the border soil
Pots
Growing tomatoes in pots ensure you that the tomatoes will always have fresh compost each year. You can also use the compost you’ve used in these pots in the plot later on. But a drawback in using pots for tomatoes is that their small size shortens their nutrient and water retention capacity.
How long will a tomato plant live in a greenhouse
A tomato plant will live in a polytunnel for years as long as the conditions are ideal. The reason behind this indefinite lifespan is because polytunnel varieties of tomatoes are indeterminate, so they continuously produce flowers and fruits as they grow. Yourpolytunneltomatoes can reach up to 40 feet in length in 10 months.
Temperature
The ideal temperature to grow tomatoes is between 70°F and 80°F during the daytime. But what temperature should polytunnel at night? Nighttime temperatures between 60°F to 65°F is best to maintain adequate warmth inside.
Keeping these temperatures ranges from daytime to nighttime will help you grow tomatoes with a high yield. However, keep in mind that both excessively high and low temperatures can also cause problems. High temperatures can yield unmarketable tomatoes, while low temperatures can affect the quality of your fruits.
You can maintain the polytunnel temperature using shade cloths, evaporative cooling pads, heating furnaces, and exhaust fans. And while you’re at it at temperature maintenance, make sure you’re regularly ventilating. Keep the polytunnel humidity below 90% to prevent mould growth.
When can tomatoes go in the unheated greenhouse
You can plant tomatoes in your unheated polytunnel after the last frost date has passed. Using an unheated polytunnel excellent for extending the growing season of your tomatoes. However, it would help if you remembered that sowing in an unheated polytunnel with frost outside puts your tomato plants at risk.
When tomatoes go in an unheated greenhouse, it’s your job to make sure the internal temperature is still ideal. Besides putting the plants after the last frost date has passed in your UK region, add protection at night. This way, you’ll be confident that the polytunnel does do not get too cold.
Feeding
You’re now familiar with the polytunnel conditions ideal for growing tomatoes. But how often do you feed tomatoes in a greenhouse? Once you transplant the plants into their final pot, you can start fertilising.
Feed your growing tomatoes every one or two weeks with a nitrogen-rich liquid fertiliser. Then, switch to a tomato fertiliser once you see fruits. Follow the instructions of the fertiliser to know how often you should feed your plants.
If you’re using liquid fertiliser, you want to skip feeding twice during the tomato plant’s life cycle. This is because it can lead to the accumulation of salts, so you should give water to wash this excess. It’s also worth noting that if you saw a sick plant, do not feed it until it recovers.
Watering
Apolytunneltomato plant requires up to 3 quarts of water per day. Make sure you’re watering your plants at regular intervals, and it can be more often in a hotter climate. However, do note that tomato leaves are sensitive, so avoid using overhead irrigation for watering.
You’ll know that your plants are not getting enough water if your plant leaves are wilted and dark green. On the contrary, yellow leaves mean that you are overwatering your tomatoes. Make sure the soil of your plants is moist and not dry or soggy.
Bottom Line
Why do tomatoes grow better in greenhouses? Yes, and it’s because of the extension of the growing season, protection against temperature and weather changes, and safe growing environment that a polytunnel offers. All these advantages will help tomatoes thrive with a higher yield than the inconsistencies with the field growing.
The best reason it’s better to grow tomatoes in a polytunnel is that you’re not limited to the growing season. So how do you grow tomatoes in a polytunnel year-round? Consider the tomato variety, season, location, temperature, feeding, and watering, and plan accordingly.
You must understand each of these advantages and factors to grow tomatoes in a polytunnel efficiently. Like growing tomatoes in the fields, preparation for various scenarios beforehand will guarantee success in growing polytunnel tomatoes. It’s not a complicated process, but it requires effort and patience on your part.
