Tomatoes are a fabulous edible food crop to grow right here in the UK. Moreover, with shortages and skyrocketing prices at local food markets, it’s always a good idea to make sure you have your own stash of tomatoes at home. Today, let’s talk about the ideal temperatures for growing tomato plants.
Growing Tomatoes in a Temperate Climate
Here in the UK, we enjoy a temperate climate where summers are warm and often wet. Temperatures rarely rise above 32° C (89.6° F). In fact, summertime temperatures usually range between 9° to 18° C (48° – 64° F) but can spike up to 30°C (86° F) during a heatwave.
For this reason and depending upon where you live in the UK, it may be best to grow tomatoes within a greenhouse where day-to-day temperatures can be regulated. In the UK, we have RHS ratings that range from H6 through H2 (USDA hardiness zones 6b through 10a).
Generally, our growing season begins in late March or early April and potentially lasts through mid-November. Put another way, we have about 204 frost-free days to enjoy growing tomato plants, as well as other garden produce. With such a long growing season and with a little help from a greenhouse, we can grow most tomato plant varieties.
If you don’t have a dedicated greenhouse for growing fruits and vegetables, you may want to consider choosing hardier varieties depending upon your local climate and growing zone. Of course, starting seeds early and/or using a greenhouse can help extend the growing season even further, which is excellent for tomatoes of the indeterminate type. If using a greenhouse, interior temperatures should range between 15° to 29° C (60° – 85° F). Be sure to use a thermometer to continuously monitor temperatures.
To further protect your tomato seedlings, you can use garden cloches or terrariums when growing outside. Garden cloches come in all kinds of shapes and sizes and act as an individual greenhouse for each plant. They are useful in the garden because they protect your delicate seedlings on cooler days and nights. Just be sure to remove them during warm and sunny days.
Temperatures Tomato Plants Can Tolerate
Tomatoes love warm and sunny daytime weather with slightly cooler evening temperatures.
Daytime Temperature Tolerances
Seeds, sprouted seedlings, and mature tomato plants like daytime temperatures that range between 21° to 27° C (70° to 80° F). However, be careful not to make your grow room or greenhouse too hot. Avoid daytime temperatures above 32° to 35° C (90° – 95° F) as this can cause heat stress, and growth may suffer. Also note, once your seeds have sprouted above the soil, you can remove any heating mats you were using to facilitate tomato seed germination.
Nighttime Temperature Tolerances
Tomato plants do need a slightly cooler evening but be sure not to let overnight temperatures dip below 12° C (55° F), as they may suffer cold damage. Additionally, tomato seeds are not likely to germinate at temperatures below 10° C (50F).
The ideal range for tomato plants at night is between 15° to 18° C (60° – 65° F). The reason you want evening temperatures to be slightly cooler is that if temperatures remain too high, your seedlings will think that they are still beneath the soil. This, in turn, will cause your tomato seedlings to become leggy. Additionally, give your tomato seedlings about 9 hours of darkness every night if starting indoors.
Once your tomato plants are living outside, be sure to monitor nighttime temperatures. If you know that your area is going to dip below 12° C (55° F), be sure to cover your plants in order to prevent damage. Do this especially in early spring and as autumn approaches.
Conclusion
Growing tomato plants and eating their luscious fruits all summer long is a cherished luxury most anyone can enjoy. At Seed Parade we have an extensive array of tomato seeds, which are hand-selected for optimal growing here in the UK. So be sure to peruse our catalogue when planning your spring garden.
