18/04/2026
When the sun appears in spring you might be tempted to plant out tender plants, but beware of late frost and cool nights! Follow these steps to work out the safest planting time in your garden:
🌱 Frost can damage or kill your tender and half-hardy plants so you should plant them out after frost risk has passed and once the nights are reliably mild, at least above 7 °C.
🌱 Before planting outdoors, you'll need to acclimatise plants that have been raised indoors or in a heated greenhouse to harden them off. Over the course of 2-3 weeks, place them in a sheltered, dappled sunny spot, gradually increasing time outdoors in the daytime, but still bringing them in at night. This is essential for tender summer plants such as dahlias in pots, coleus, salvias, tomatoes, basil, peppers and French beans.
🌱 After hardening off, plant them out when the nights are consistently above 7 °C. Some common heat-loving edibles, including tomatoes, peppers, basil and cucurbits, do better if nights are above 10 °C.
🌱 If an unexpected chill is forecast, cover your plants with reused or biodegradable fleece. Use a double layer on the coldest nights.
Find out more on when to plant out tender plants:
https://www.rhs.org.uk/garden-jobs/when-to-plant-out-tender-plants-avoiding-late-frosts