Here we focus on those scientific concepts that are the hardest to explain to children. We break it down into what pupils need to know and outline the background science. Even though much of the background science does not need to be taught to primary aged children, it is useful for you as a teacher when addressing misconceptions and children’s challenging questions.

Please refer to your national curriculum documents when planning your sequence of work and ensure that you teach the correct knowledge for your year group.

What do children need to know about plants?

Pupils develop their understanding of plants gradually and it is important that the progression of knowledge is built on at each stage. Observing, handling, and growing their own plants is key to this development. It is also vital to make clear links to their learning in related topics: living things and their habitats, animals including humans, evolution and inheritance. We have included some ideas for how to teach plants in part two of this topic guide.

Key scientific concepts: Pupils need to...

1. Identify a variety of common plants and describe their basic structure, using their characteristics to group and classify them

2. Explore how plants vary in what they need to grow and develop healthily 

3. Describe the life cycles of plants

1. Identify a variety of common plants and describe their basic structure, using their characteristics to group and classify them

Pupils need to know: 

• That there is a huge variety of plants that can be identified by their characteristics

• The basic structure of common plants and the functions of each part (including leaves, flowers (blossom), petals, fruit, roots, bulb, seed, trunk, branches, stem)

• The difference between deciduous and evergreen trees

Background science

The word ‘plant’ encompasses a huge range of living organisms, including trees, shrubs, herbs, grasses, ferns, and mosses, that share certain key characteristics:

• They make their own food (converting the sun’s energy into food through photosynthesis)

• They are generally rooted in one place (although some can turn their leaves to face the sun or respond to touch)

Plants, like all living things, can be classified into broad groups and then divided into smaller and smaller groups. For example, plants can be split into those with seeds and those without seeds. Plants with seeds can then be divided into flowering or non-flowering plants. Seedless plants, which reproduce by spreading spores, can be split into those with roots, stems and leaves (e.g., ferns) and those without true roots, stems and leaves (e.g., mosses). 

Things to look for when using observation to classify plants are:

• Leaves: shape, size, colour, texture, arrangement on the stem etc.

• Flowers, berries and cones: colour, size, shape etc.

• Bark: texture, colour, roots, trunk shape, branch position and height

Deciduous trees (e.g., oak, beech, ash) shed their leaves every year when the weather turns colder and light levels drop. Evergreen trees (e.g., fir) keep their leaves all year. They need to be specially adapted to make sure that they survive the tough conditions of winter. They tend to be darker green so that they can make the most of the lower light levels. They tend to be stiff and waxy to protect themselves from drying out in the wind or being shrivelled by the cold. Some evergreens even contain special substances to stop their leaves from freezing. Evergreens also need to protect themselves from being eaten by hungry animals when there is not much other food around, so their leaves are tough, or prickly or do not taste very nice.

2. Plants vary in what they need to grow and develop healthily

Pupils need to know: 

• That most plants need water, air, nutrients, sunlight and enough space to grow and develop healthily 

• How each plant has different requirements in order to flourish

Background science

The five basic essentials for most plants are:

1. Light: Usually from the Sun, but plants can also grow in artificial light. Plants use light energy to make a type of sugar called glucose, which is their source of energy. Plants make glucose in a part of their leaf cells called the chloroplast. Each chloroplast contains a green pigment called chlorophyll, which allows the plant to absorb light energy

2. Air: Carbon dioxide from the air is combined with water during photosynthesis (using the light energy from the sun) in a chemical reaction to create glucose and water

3. Water: Plants need water for photosynthesis. Absorbed by the roots, water travels through a plant’s stems to the chloroplasts in the leaves. Water also helps move nutrients from the soil into the plant, as well as helping to keep the stems upright (by pressing against the plant’s cell wall, known as turgor pressure)

4. Nutrients: Substances (e.g., nitrogen, phosphorus and potassium) found in the soil help to nourish a plant. When dissolved in water, these nutrients get absorbed by a plant’s roots. If a plant can’t get the nutrients it needs from the soil, fertilizer can help. Fertilizer provides plants with essential nutrients and helps them grow faster

5. Space to grow: All living things need space. A plant’s roots need space so that they can spread out and absorb water and nutrients. Its leaves need space so that they access light. When plants grow too close together, they have to compete for these resources

Even though most plants require air, water, nutrients, sunlight and enough space to grow, there is variation in how much of each of them different plants need to flourish. This is, of course, related to the conditions in their natural habitat and how they have adapted to survive over time. For example, some cacti survive in harsh, dry desert climates because they have a thick fleshy stem that acts like a huge sponge to absorb lots of water when it does rain. Lichens can grow in all sorts of places as they don’t need soil to grow and can absorb water from different surfaces. Many types of fern are suited to shady conditions, using their large, dark green leaves to make the most of less sunlight.

It is also important to be aware when planting seeds and bulbs that, as they are planted in the ground, they receive no sunlight (only nutrients and water) so they must use energy stored in the bulb or seed.

3. Describe the life cycles of plants

Pupils need to know: 

• Seeds and bulbs grow into mature plants

• The life cycles of a range of plants, including pollination, seed formation and seed dispersal 

• The process of reproduction in some plants 

• That plants have evolved over time as a result of adaptation

Background science

Plants reproduce in different ways. Some reproduce asexually (i.e., the offspring only have one parent). Asexual reproduction produces plants that are genetically identical to the parent plant.

Methods of plant asexual reproduction include:

1. Spores: Found on non-seed-bearing plants (e.g., green algae, mosses and ferns) spores are reproductive cells that can develop into a new individual without fusing with another cell. A spore cell has everything it needs to grow into a plant, and under favourable conditions, the cell will divide and grow. They are transported to new areas by wind or rain

2. Bulbs and tubers: Underground food storage organs that store food and can grow and develop into new plants (e.g., onions, garlic, potatoes)

3. Plantlets/Runners: Plants develop miniature plantlets at the edge of their leaves, which eventually drop off and develop into plants (e.g., strawberry or spider plants)

4. Cuttings: If you take a cutting from a parent plant and replant it, it will be able to develop roots and grow into a mature plant

The remainder of plants reproduce sexually (i.e., offspring with parents from each sex) by releasing gametes (male and female reproductive cells - sperm and eggs). Sexual reproduction produces genetic variation in the offspring, which means that a species can adapt to environmental changes, giving them a survival advantage. Fossilised remains of plants provide us with information about extinct plants and adaptations over time. The Eden Project has created a guide to prehistoric plants. See the topic guides on evolution and inheritance for more information on this.

For plants that reproduce sexually, there are differences depending on their reproductive organs:

• Flowers: Flowers provide the mechanisms for sperm to find eggs, thus leading to fertilization and the development of seeds. The outermost parts of the flower which typically surround the rest of the flower are green structures called sepals. Inside of the sepals are the petals, which are typically colourful. Next are the stamens, each of which contains a filament topped by pollen-producing cells. The innermost part of the flower is the carpel, which contains the ovary (where the eggs are located). The pollen (the male part or sperm) from another flower must enter the ovary and fertilize the ovule in order for a seed to start developing

• Seeds: Seeds are dormant, storing energy which they use to grow into mature plants. Seeds can be dispersed (sent to new places) by wind, water or by animals, their barbs catching on animal’s fur or being eaten and dispersed through an animal's droppings. Seeds take many forms, sometimes being covered by the scales of cones or with a fleshy or hard fruit

In learning about the lifecycles of plants, it is important children learn about the interdependence of living things. Plants are a source of food and shelter for animals and animals produce waste, which decomposes to provide nutrients for plants. Through their experiences of growing plants, children develop an understanding of how plants form an essential part of the diets of many living things, including humans. Younger children can use this knowledge when constructing simple food chains and older children will need to be able to connect what they know to creating a balanced diet.

Ideas to try with your class 

Now you've got the tricky scientific concepts under your belt, try our ideas to help you explore plants with your class in a way they will understand in part two of this topic guide!

You can also take a look at the related topic guides for living things and their habitats, evolution, inheritance, animals including humans, light. 

Image credit: A flower bed including blue, pink and purple spring flowers by Capri23auto via Pixabay