For those of us who grow tomatoes in a greenhouse and outside in the garden, there is no competition – the greenhouse wins every time!
The patio is fine for growing bush varieties in large pots and hanging baskets or tall varieties up against a wall in grow bags, but to guarantee a successful crop each season, a greenhouse is the best place to grow tomatoes.
If you live in a short season area such as the UK, a greenhouse has the benefit of being able to start sowing earlier in the season.
This will enable you to still be picking tomatoes when plants that were grown outside have long finished.
In a greenhouse, tomato plants are out of the rain, also temperatures won’t drop so low at night.
The combination of wet leaves and cold temperatures for more than a day or two, will have a serious effect on a tomato plant’s health.
This is owing to blight and the many other fungal diseases waiting to strike plants that are both wet and cold.
When a tomato plant growing outside has wet leaves, it is unable to absorb water through its roots, therefore, the nutrients that the water carries, is not taken up by the plant.
It then goes hungry and is more vulnerable to diseases. In contrast, a plant grown in a greenhouse with dry leaves, will be able to absorb nutrients whenever it wishes and will grow at a more consistent rate.
Temperatures fluctuate less widely inside than those outside in the garden, so this will also aid steady growth and encourage pollination and flower set. Getting flowers to set fruit can be a real problem if it gets too cold at night.
A greenhouse also has the benefit of being able to shade tomatoes from direct sunlight.
This may seem rather strange – shielding plants from the sun! However, some tomato varieties, especially those that originate from cooler climates, such as many of the black varieties, prefer diffused sunlight on a hot summer’s day. So setting up a sheet of garden fleece, or using some other means of shading between the hot sun and seedlings, is easy.
The ability to control temperatures in a greenhouse enables optimum plant growth.
We all know that tomato plants like warm conditions, but warm conditions enable plants to feed regularly.
When temperatures are too low, nutrients are unable to be absorbed, so cold plants are also hungry plants – just like wet plants are hungry plants!
Of course, good ventilation is necessary to avoid high humidity and condensation.
Tomato plants need good air circulation and if doors are closed on a greenhouse full of tomato plants, they will soon use up the carbon dioxide in the air and their growth will slow down.
To sum up, the benefits of growing tomatoes in a greenhouse allow us to focus on actually growing the fruit, rather than just hoping that we will get a crop, and that our plants will make it through to the end of the season!