Red spider mites

A table displaying which months are best to sow, plant and harvest.
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Time to act
Time to act

Do Time to act in January

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Do Time to act in April

Do Time to act in May

Do Time to act in June

Do Time to act in July

Do Time to act in August

Do Time to act in September

Do Time to act in October

Do Time to act in November

Do Time to act in December

These tiny, sap-sucking pests may be only 0.5mm long but they can wreak havoc in a greenhouse or on houseplants indoors. For most of the year they are a pale green colour with two dark spots on their back; it’s only in autumn and winter that they turn orange-red. They thrive in hot, dry conditions so life in the greenhouse, or a centrally-heated home, suits them just fine. If the temperature stays above 12 celsius, they can breed all year round.



Leaves and stems of plants covered in fine webbing. The upper surface of the leaf is mottled, while mites and eggs can be seen with a magnifying glass on the undersides of leaves. The plant may die.

Find it on

houseplants, greenhouse plants, also outdoors on fuchsias, runner beans, busy lizzies, grape vines



Improve air circulation in the greenhouse and boost levels of humidity by misting plants with tepid water and standing bowls of water on the benches between plants. Damping down the floor of the greenhouse with water will also help. When daytime temperatures in the greenhouse hover steadily around 21 celsius, you can try releasing the predatory mite, Phytoseiulus persimilis on to your plants. Alternatively, use sprays containing, fatty acids or plant oils.