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How to build a potato clock

You will need:

  • a digital clock
  • two potatoes
  • wire
  • zinc plate
  • copper plate

Buy the parts at an electronics shop.


  • Check all the wires are securely connected (see diagram).
  • Put one copper plate and one zinc plate into each potato. The plates need to be about two centimetres deep, and about two centimetres apart.
  • Set the time on your clock – it should now be working.

How does it work?
Potatoes are full of a mineral called phosphoric acid, which reacts differently with each of the metal plates (one copper and one zinc) in your potato. Phosphoric acid dissolves the zinc plate, freeing electrons, which react with the copper plate to form hydrogen gas.

The potato acts as a superhighway of electrons between the copper and zinc plates. This flow of electrons is the electrical current that makes your clock work.

Header education growing potatoes in a bucketGrowing potatoes in a bucket

You can grow your own potatoes in a bucket – they will take around 60-70 days and then they will be ready to be harvested.

Growing your potato

Plants need light, water, food, space, air and the correct temperature to grow really well.

Plants need light to grow, so put the potato plant somewhere in the light.

Potatoes need water to grow, but don’t water it too much or the potato will go mouldy. The soil should be damp so water every 3-4 days.

Potatoes need food to grow and this comes from the nutrients in the soil. Compost should contain everything your potato needs. If extra potato food is added make sure to read the instructions carefully.

The ideal temperature for growing potatoes is 10-15°C.

The more room the plant has the better so even though these instructions are for growing potatoes in a bucket, potatoes planted in the garden will give better results.

Note: Do not eat any of the growing potato plant – only the potatoes can be eaten.

Planting instructions

You will need:

  • a bucket
  • 1 seed potato
  • compost or soil

Make sure your seed potato is starting to sprout before planting. If there are no sprouts the potato may take ages to start to grow so place it on a windowsill until you see the sprouts coming through.

Make a drainage hole in the bottom of a bucket; an adult should do this. It can be done using a hammer and nail.

Place enough fresh dry topsoil in the bucket so it is about one third full.

Push in one seed potato per bucket and make sure it is covered with 1 cm soil.

Water the soil so it is damp; you will need about one cup of water. The soil should only be damp, not wet. The potato does not need much water until the top is growing.

Place the bucket in a warm and sunny spot. The plants will need sunshine, this can be indoors beside a window or outdoors. The plant will respond well to being outside in the sunshine but if you are growing them over winter they must come in at night to be protected from frosts. It is essential that the plant is not frosted.

Once the shoots appear keep the soil damp but not wet. If it does get over-watered put it in the sun without extra water until it is back to being damp. Over-watering will slow growth.

Once the tops start to die off the potatoes are ready to harvest. This will take around 60-70 days.

Inspire children to bake a potato

A practical guide to baking potatoes – how to impart skills and foster personal responsibility.

Our vision has a vision that every New Zealand child will have the skill to bake a potato.

We believe if ‘a child can bake a potato – they can make a meal.

This programme is based on the philosophy that ‘if you give a man a fish, you feed him for lunch. If you teach a man to fish, you feed him for a lifetime.’ By teaching a child to bake a potato, they will have a skill to feed themselves for their lifetime.

This is a practical and achievable way to encourage simple, healthy food choices and for children to know that ‘a full tummy is only one potato away’.

With your support we can make a difference.

Keep it simple

The purpose of this strategy is to take a potato and turn it into a complete meal with maximum taste and nutrition with a minimum of fuss and expense. We want to give children a positive potato experience that will motivate and inspire them to bake a potato often.

This strategy is a fantastic opportunity to establish good eating habits by encouraging the consumption of a food which is:

  • easy to prepare
  • nutritious
  • readily available
  • economically attainable
  • popular and tasty
  • locally grown
  • environmentally sustainable
  • an integral part of our culture.

Get support

Involve grandparents, older neighbours or friends of the children, many of whom may have time to support the children. You may be surprised with their enthusiasm and passion. Older adults were bought up on potatoes and it is a very tangible and positive thing that they can do with these children. has great resources to inspire them. We want to keep the Kiwi potato eating tradition alive because it brings so many benefits to all.

Look for helpful resources in our Resources section.

Resources in Maori and Samoan

Some of our free resources are available in English, Maori and Samoan. Look for them in our Resources section.

The take-home messages

  • ‘I can bake a potato, so I can make a meal.’
  • ‘When I am hungry I can bake a potato and fill my tummy.’
  • ‘I know potatoes taste fantastic.’
  • ‘Potatoes are great for me because they have lots of fibre, vitamin C and they give me energy without fat. They will fill me up.’
  • ‘Potatoes are good for the planet – they are really efficient plants and use much less water than other crops.’
  • ‘Potatoes give me more nutrition per unit of land, water and money than any other major staple crop.’