Growing nasturtiums in a school garden to support large white butterflies

Teach butterfly life cycles and food chains by supporting butterflies with food for their caterpillars.

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Large white butterfly caterpillars feeding on nasturtium leaves
Large white butterfly caterpillars feeding on nasturtium leaves

Quick facts

Learning objectives:
  • Understand the life cycle of a butterfly
  • Describe a simple food chain
  • Explain how growing nasturtiums in school grounds can help large white butterflies
Curriculum links:
  • Science: how animals obtain food from plants and other animals, food chains (identifying producers, predators and prey), insect life cycles
  • PSHE: how pupils can help look after their environment, how everyday choices can affect the environment

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Why grow plants for butterflies?

Growing nectar and pollen-rich flowers at school for moths and butterflies to feed on is a great way to help wildlife. By also providing food for their caterpillars, we can help them to grow into the adults that we love to see visiting the flowers in our school grounds.

Different types of caterpillars feed on different types of plants. Some types of caterpillars have a very narrow diet and will only eat one or two types of plant. For example, small tortoiseshell butterfly caterpillars mainly eat nettles.

Why are caterpillars important?

  • Caterpillars are an important part of food chains (see food chain diagram below). This is especially the case for birds, such as bluetits and robins, which feed them to their chicks
  • The butterflies and moths they become are pollinators, helping plants produce seeds that grow into new plants
Large white butterfly catterpillar as part of a food chain

Large white butterfly life cycle

The adult butterfly lays her yellow eggs on the leaves of the caterpillars’ food plants, such as nasturtiums. When the caterpillars hatch out of the eggs, they can start eating straight away.

As the days and weeks pass, the caterpillars eat more and more leaves, growing larger. As a caterpillar grows, its skin does not grow with it. To become larger, it must shed its skin. Large white butterflies shed their skin five times; after the fifth, they are fully grown.
Female large white butterfly laying eggs on a leaf
Large white butterfly caterpillars eating nasturtium leaves
Once it is fully grown, the caterpillar turns into a pupa. Depending on the time of year, it will remain as a pupa for between two weeks and eight months, as it changes into a butterfly. When it emerges from the pupa as an adult butterfly, it looks for nectar-rich flowers to feed on. The nectar gives it the energy it needs to fly, find a mate and produce eggs. Then the cycle begins again.

Large white butterfly pupa
Large white butterfly life cycle

How can you help large white butterfly caterpillars?

By growing nasturtium plants at your school, you can help feed the caterpillars of the large white butterfly, which feed on the leaves. Nasturtiums grow well in containers or in the ground. Find out how to grow them here.
Nasturtium plant, showing flowers and leaves
Large white butterfly adult
Please note: Although large white caterpillars prefer nasturtiums, they will also eat many kinds of cabbages. If you are growing cabbages at school, check their leaves regularly and gently move any large white butterfly caterpillars to your nasturtiums.

Reflection questions

  • Have you seen any butterflies or caterpillars in your school grounds recently?
  • Can you think of a place at school where you could grow nasturtiums for caterpillars?
Remind pupils to look from a distance and check with an adult before touching any caterpillars.

Key words

Mate When a female has partnered with a male to produce young.
Nectar Sweet liquid mainly produced by flowers to attract pollinators.
Pollen Dust-like grains produced by the male part of the flower.
Predator An animal that hunts, kills and eats other animals.
Primary consumer A living thing that can’t make its own food, so must eat plants to get the energy it needs.
Producer A living thing that makes its own food instead of eating other living things, for example green plants.
Secondary consumer An animal that eats a primary consumer.

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