How to grow a cress caterpillar

By Lisa Hendry

A fun food-based activity to keep kids entertained at home.

Create a colourful caterpillar, watch cress grow and eat the tasty results.

Follow our simple instructions to transform eggshells and cress seeds into a caterpillar.

There are hundreds of types of caterpillar in the UK to choose from. We've highlighted a selection of interesting ones for inspiration.

How long does cress take to grow?

Cress grows quickly. You should start to see your seeds sprouting within a few days and often in as little as 24 hours. After seven days, the cress will usually have grown at least three centimetres tall and be ready to harvest.

You will need:

eggshells, clean and dry
cress seeds - sometimes called salad or garden cress (Lepidium sativum)
craft supplies, such as non-toxic poster paint
water
cotton wool
salt dough or play dough

What to do

Pick which caterpillar you want to make. Check out the photos below for ideas.
Decorate the eggshells to match your chosen caterpillar's colours and patterns. Leave them to dry.
Roll some little balls of salt dough to make caterpillar legs. Attach four to the bottom of each eggshell.
Submerge some cotton wool in water and place a piece inside every eggshell.
Sprinkle a teaspoon of cress seeds onto each one.
Place your caterpillar in a warm, sunny spot.
Check it daily. If the cotton wool looks dry, add some water. After a few days the seeds will start to sprout. Your cress should be ready to harvest in about a week.
Harvest and wash your cress. Use it to make a tasty salad or sandwich.

Caterpillar inspiration

Caterpillars are the second stage in the lives of butterflies and moths.

There are 59 different types of butterfly in the UK and just under 2,500 types of moth.

Here's a selection of colourful British caterpillars with dramatic patterns to use as inspiration for decorating your eggshells:

A lime-green caterpillar with a mixture of black and orange dots and blobs around its body segments

Swallowtail butterfly caterpillar (Papilio machaon)

A yellow- and black-striped caterpillar, which has some hairs, on a plant with yellow flowers

Cinnabar moth caterpillar (Tyria jacobaeae)

A white caterpillar that has big yellow blobs and smaller black dots on each segment, plus some black hairs

Mullein moth caterpillar (Cucullia verbasci)

A yellow and pale green caterpillar with lots of irregular-shaped black blobs and white hairs, which is on a broccoli head

Large white or cabbage white butterfly caterpillar (Pieris brassicae)

Side view of a brownish caterpillar with two very noticeable eyespots and what looks like a little pointed black tail

Elephant hawkmoth caterpillar (Deilephila elpenor)

A vivid green caterpillar with about 12 segments that have multiple black-circled white bumps with hairs growing out of them

Emperor moth caterpillar (Saturnia pavonia)

A chunky looking yellow caterpillar that has a mixture of pale green areas, bluish-purple diagonal stripes with lots of tiny black dots, an additional black spot per segment and what looks like a little yellow tail

Death's-head hawkmoth (Acherontia atropos)

A black caterpillar with tiny white spots, lots of black spikes and four red prolegs visible

Peacock butterfly caterpillar (Aglais io)

A chunky green caterpillar that has a red face and two false eyes, a brown, white-bordered saddle and two long, black-and-white tails with red tips

Puss moth caterpillar (Cerura vinula)

A very hairy caterpillar with a greyish-blue face, two false eyes and orange, black, white and greyish-blue stripes along its body

Lackey moth caterpillar (Malacosoma neustria)

A dark-brown caterpillar with red spots and white dashes along its side, orange dots and more white dashes along its back and tufts of long brown hairs

Knot-grass moth caterpillar (Acronicta rumicis)

A dark-green caterpillar with thin yellow and broader dark-grey stripes along its body and a pinkish-brown head

Broom moth caterpillar (Ceramica pisi)

A black caterpillar with spiky hairs on its back and multiple orange, twisted stripes - much of its back looks like a white bird dropping

Comma butterfly caterpillar (Polygonia c-album)

A quite hairy grey caterpillar with a white stripe along its side under pairs of red dashes, a pale yellow stripe along its back and a tall black hump close to its head

Grey dagger moth caterpillar (Acronicta psi)

A dark green caterpillar with a pattern of small white and yellow-and-white blobs all over its body

Beautiful yellow underwing moth (Anarta myrtilli)

A black caterpillar with two orange stripes running down its back, multiple white patches either side and lots of very long hairs

Yellow-tail moth caterpillar (Euproctis similis)

A lime-green caterpillar with reddish-pink streaks along its side and a pink-and-bluish horn-like projection at its tail end

Lime hawkmoth (Mimas tiliae)

A grey caterpillar that has golden speckles and tufts of white hairs along its sides as well as being covered in brown hairs

Drinker moth caterpillar (Euthrix potatoria)

Colourful caterpillars

Many caterpillars are dull browns and greens, which helps them stay hidden on leaves and branches.

Others have gone for the opposite approach and are decorated with vivid colours and patterns. This is to warn predators such as birds that they taste bad or are dangerous to eat, or to at least fool the predators into believing this.

Some caterpillars even develop disguises that, combined with particular behaviour, startle predators. For example, the eyespots of the elephant hawkmoth caterpillar are thought to make it look like a more intimidating animal.

How many legs does a caterpillar have?

Like other insects, caterpillars have six proper legs. They are attached to the part of their body nearest their head. Caterpillars have additional stumpy body parts called prolegs towards the back of their body that help them move around. They use them to grip onto twigs, stems and other surfaces.

Different caterpillar species have different numbers of prolegs - between two and five pairs. So, caterpillars can look like they have up to 16 legs, although only six are true legs with joints like our knees and ankles.