Gardening Terminology: Strange Gardening & Botanical Words That Are Important For Gardeners


Learning About Gardening Can Be Confusing With All The New Gardening Words And Names To Remember. So I Asked Gardeners The Following Questions About Gardening Terminology and Wrote a Gardening Dictionary to Help Them Master The Words And Enjoy Their Gardening. It’s Not Made Easier By the Fact Some Of These Words Are Historical And Some Very New.

Which gardening terms confuse you?

What gardening terms are new to you?

What gardening terms do you want explaining?

This dictionary is a work in progress, I’m starting at the beginning with A .. and slowly working through the alphabet. It’ll take time so please bear with me and come back as I write each new instalment!




Gardening Terminology – A 

Abscission Layer

A layer of cells at the base of the petiole (leaf stem) where the leaf breaks away in autumn. Technically there are two layers of cells, in autumn the bottom one expands and breaks away from the top layer. It is believed that reduced sunlight and daylight hours leads to a reduction in photosynthesis and hence a reduction in chlorophyll production which then prompts abscission. in autumn.

Acid Soil

Soil can be acid, neutral or alkaline and is measured on a pH scale of 0-14 with 7 being neutral. Acid soils are technically in the pH 0-7 range. However the most acid soils rarely exceed pH3 and few plants can survive very acid conditions.

The plants that enjoy, and in some cases require acid soils include blueberries, heathers, rhododendrons, azaleas etc. For example, most rhododendron species prefer a pH of 4.5-6. Naturally occurring acid soils are found in bogs (hence peat is acidic), moorlands and coniferous forests.

Ericaceous composts are acid and used to grow acid loving plants.


A measure of land totalling 43560 square feet (UK measurements). If its square that’s about 209 feet on each side. There are 2.471 acres in a hectare. Land in the UK is still sold in acres.

To confuse matters even further, historically an acre was a furlong by a chain. Roughly speaking this is the size of a football pitch (which can be anything between 100-130 yards long and 50-100 yards wide .. even square according to the rules!).

Aerate / Aeration

Aerating consists of loosening the soil surface to encourage water and air penetration. It can be done by hoeing and other cultivation practices and is useful to prevent evaporation during hot weather.


Air is often forgotten as an essential for plant growth. In most plants air is taken in via the roots and soil or compost needs to be air permeable to allow for gaseous exchange at root level.

Air drainage

Hot air rises and cold air descends. Air drainage is when cold air flows down a slope. In cold weather this can lead to frost pockets ate the bottom of the slope, where the cold air lays in low spots.

Air layering

A form of plant propagation where the cutting is allowed to root into a growing substrate whilst still attached to the parent plant. Some form of damage to the bark, where rooting is required, induces quicker rooting. To prevent that substrate from drying out the stem and substrate is normally wrapped in plastic to retain moisture.

Alkaline soil

The opposite end of the pH scale to acid soils .. see above.


The onion family. There are hundreds of species within this family which includes onions, spring onions, garlic, shallots, etc

Alternate leaves

A plant leaf structure where the leaves appear alternately along the stem as opposed to opposite or in some other structured way


A plant that lives for up to a year. They can go from seed to mature seeding plant in no more than a year. Some weeds can actually achieve this in six weeks … it’s why they are so successful at being weeds!


The part of the flower that produces the pollen. It is on the upper part of the stamen.


A fungal disease affecting leaves and fruit


A small sucking insect that sucks the sap from plants. Aphid are parthenogenic and hence capable of virgin birth. Most adults don’t have wings but every so often a winged generation occurs and they fly to infest new plants. Aphid are unusual in the insect kingdom in that they give birth to live young and are not normally egg-laying. There are huge numbers of aphid species and they range n colour from green to pink and even black (often call the black army when infesting broad beans).

Apical dominance

The botanical term that describes the process whereby the main stem of a plant is dominant over the branches and side shoots and where branches are dominant over sub-branches. The process is controlled by plant hormones, auxins, produced in the growing tip. Thus the dominant plant growth is upwards towards better light where photosynthesis is maximised. Should the leading shoot be destroyed or damaged a secondary shoot will become dominant due to the lower auxin level. It then produces auxins to become dominant in its own right. 


A collection of trees and shrubs; often gathered together for scientific or educational purposes, or as in the case of some collectors to demonstrate wealth or intellectual prowess!

Normally arboreta are found in parks or private gardens. Examples in the UK include the National Arboretum at Westonbirt which belongs to Forestry England and Sidmouth arboretum which is unusual in not being a single site in single ownership. Sidmouth Arboretum is a collection of trees and shrubs spread across the whole of the Sid Valley, in the ownership of a number of private individuals and public bodies and organisations.


The cultivation of trees and shrubs as individuals and small groups as opposed to forestry which is the planting, growing and harvesting trees en masse for timber. Arboriculturists work with both ornamental and edible crop bearing trees such as apples, cherries, etc.


A tool designed to take soil samples from various depths OR a tool that makes holes to enable the planting of bulbs, plugs, or container/module or pot grown plants. Augers that fit in hand drills are particularly easy to use and can make planting much quicker. (Please follow the safety instructions provided with your auger).


The leaf axil is the joint between the leaf and stem on a plant. This area is where shoots often emerge. An example would be tomatoes where the shoot coming from the axil is the side shoot.

Axillary bud

The bud produced in the leaf axil.

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Check out our How to Dig For Victory Group Feed below ….. or scroll down for B

How to Dig for Victory
How to Dig for Victory
Gardening Terminology

New or not to gardening, some of the terminology can be confusing. So today I’m looking at three words that can be used to describe every plant you’ll ever grow.


A plant that lives for up to a year. They can go from seed to mature seeding plant in no more than a year. Some weeds can actually achieve this in six weeks ... it’s why they are so successful at being weeds!


These are plants that take two years to go from seed to seeding adult. Lots of veg are biennials, eg lettuce, leeks, carrots, beetroot, but we tend to eat them in year one so never see them flower. It’s a pity we don’t see them as some are magnificent, leeks, for example, can be six feet high when flowering and have a huge head of flowers


Perennials are long lasting and may seed many times during their lifetime. Trees are a prime example, think how many acorns an oak will produce in a lifetime that spans centuries. So fruit trees, fruit bushes and even strawberries are perennial. But we aren’t limited to fruit. Perennial kale and asparagus have long lifetimes and keep producing fruit, leaves etc.
How to Dig for Victory
How to Dig for Victory
What Vegetable Seeds Can I Sow In June (or any other month) In The UK? Is a frequently asked question on How to Dig for Victory

Here’s the answer for June Sowing in the U.K. there are dozens of seeds that can be sown this month.
How to Dig for Victory
How to Dig for Victory
With queues in supermarkets, I wanted to create a group where we can discuss small scale home food production and waste avoidance. Not only because every lettuce or cabbage produced in our gardens and window boxes is one that doesn’t have to be queued for, but also because growing plants is great therapy in these troubled times.
This is a group for beginners and those with more experience to share experience, advice and ask questions.

Join over 900 people in the main group
How to Dig for Victory
How to Dig for Victory
Potatoes are very easy to grow. These are grown in a very large container though most are grown direct in the soil without a pot.
The reason these are in a container is that I started them very early in the season. They were planted in February and kept in the greenhouse until they were in leaf. Now they are outdoors and loving the weather here as it warms up a bit. Because frost would kill them I am still covering them with horticultural fleece at night.
More on potatoes later as there is plenty of time to grow them outdoors or in containers over the next few months in the U.K.
How to Dig for Victory
How to Dig for Victory
Gardening for Kids: Growing Micro Greens

Here’s a great way to quickly get children interested in, and eating, their own veg.

Grow micro greens on a windowsill.

All you need is a container with drainage, fill it with compost and sow seeds of crops like cress, mustard, broccoli, basil, spinach etc. Keep the compost moist.

Once the seedlings have a few leaves they can be snipped with scissors and tasted for flavour.

Ask the children why seeds are different shapes and sizes, what they might look and taste like, what they taste like etc.

Ask why the seeds need light, warmth and moisture. Is this the same for pets and people?

Put different pots in different places to see how temperature and light affect growth. Ask the children what they expect, let them draw what they expect.

What actually happens? Draw this.

Let the kids paint or draw on the pots before planting.

There are lots of variations on this seed sowing theme. What will you investigate with your kids?

You can share children’s pictures and results here.


Gardening Terminology – B

Bare Root

Plants such as fruit canes are sometimes sold as bare-root plants rather than in pots. They will have little or no soil around the roots and will be protected from drying out by being wrapped in paper or an alternative cover.

Don’t think that if you’re offered a bundle of plants in a single pot they are necessarily pot-grown. They are often bare-root plants put in a pot to lengthen their shelf life. They weren’t grown as a clump of plants.

Bare root plants are best planted in the autumn when they are more likely to root and establish rather than in hot dry weather when they can dry out and die.


The bark of a tree or shrub is the hard outer layer that covers the roots, stems or trunk. Several other structures exist below the bark including cambium, phloem etc. The outer bark consists of dead tissue whilst the inner bark is living and includes the inner layers of the periderm.

Bark can be harvested for several purposes including as cork for the making of cork goods and as a bottle closure. Oak bark is used in the tanning process. Other barks produce spices, eg cinnamon bark, latex and poisons.

Bark is often visually attractive and many trees are grown for this reason. e.g cornus species.

Bark is also used as a ground cover in pathways and on beds as a mulch.


As in a blade of grass. Its the flattened green part of the leaf.


These are plants that take two years to go from seed to seeding adult. Lots of veg are biennials, eg lettuce, leeks, carrots, beetroot, but we tend to eat them in year one so never see them flower. It’s a pity we don’t see them as some are magnificent, leeks, for example, can be six feet high when flowering and have a huge head of flowers.

snails grazing on food crops can be controlled with nematodes - Gardening Terminology

Biological Control

The use of biological agents to reduce pests. E.g the parasitic Encarsia formosa wasp to control whitefly. Other examples include Bacillus thuringiensis to control caterpillars and nematodes to control slugs and snails.


Gardening Terminology -Bipinnate leaf structure
Bipinnate leaves

A leaf structure where the leaf is compound with a paired leaf of feather-like leaves. Each pair is also divided into pairs 


When a plant bolts it means it’s going to seed. This is exactly what we want if we harvest the seed or fruit. But not so desirable if we want the root or foliage. Premature bolting is often caused by water stress .. ie underwatering or overwatering.

Bone meal

A phosphorus-rich fertiliser made from finely ground up animal bones. Phosphorus promotes strong root systems and is part of a normal general-purpose fertilizer.


The scientific study of plants including their physiology, structure, ecology, genetics, classification and economic importance.


Botrytis cinerea is a fungus, often called grey mould or grey rot, that infects a wide range of fruit, veg and flowers. It tends to be more prevalent in wet or moist conditions and often infects plants that have been damaged in some way. Eg. tomatoes that split due to sudden increases in irrigation will frequently get botrytis. It is also very common on strawberries and grapes.

Botrytis is necrotrophic, ie it lives on dead plant material. In many cases infecting damaged plants and subsequently causing their death.


The modified leaves, often sitting below the flower, that are often mistaken for the flower. Examples include poinsettias and some dogwoods (Cornus species).


The cabbage and mustard family. The genera includes many species and cultivars. Eg Brussel sprouts, cauliflower, kale, turnip, kohlrabi, broccoli, calabrese, pak choi, swede, etc


No, not a media term! In this case, it means to broadcast seed, ie to spread seed widely by hand or with a machine.  A hand-operated machine called a seed fiddle can be used to sow seed.  I’ve used one myself to sow grass seed and it’s claimed that it can be used to sow wildflower seed. However, the problem with using it for mixed seed is that each seed has a different weight and therefore is broadcast a different distance. This means there is a tendency to get stripes in the field where the lighter seed hasn’t reached! The video shows a seed fiddle being used in Scotland, and the accent may need some careful listening if you are to understand it fully. 



Buds are undeveloped or embryonic shoots and what leaves, flowers and subsequent seeds or fruit will develop from.


An underground storage organ typical of the daffodil and lily families. It is effectively a self-contained bud, that can remain dormant when growing conditions aren’t good, that can be detached from the parent plant and will remain viable. It consists of a stem surrounded by fleshy scale leaves and flower. The embryonic flower is contained within the bud and will have formed between the time the plant last flowered and the time the bulb was finally formed. Blind bulbs have no flower embryo and are usually formed when the plant has been too dry after flowering or the foliage has been damaged before the bulb has been fully formed.

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Gardening Terminology – C


Chalky soils are largely calcium carbonate based and hence lime rich. They are very alkaline eg. pH of 7.1-8.0, they will often froth if mixed with a mild acid such as vinegar. Where this occurs it demonstrates the presence of free calcium carbonate.

Chalky soils are highly visible. They appear to be white, or at least have small pieces of chalk in them.

Chalky soils are often shallow and overlie clay. The chalk itself will be free draining but the underlying clay will be wet and cold. This makes it a difficult soil to cultivate and grow crops in. Organic matter such us composts can be added to improve fertility but it decomposes quite rapidly.

Poor growth and chlorosis are common on chalky soils. This is due to plants not being able to absorb sufficient iron and manganese due to the alkaline conditions.


Chlorosis, and chlorotic growth, are characterised by yellowing of leaves due to the lack of chlorophyll. Although indicative of various adverse conditions such as poor light, pest and disease including viruses, poor nutrition, waterlogging, drought, low temperatures, incorrect pH or other cultural problems it is also natural in some cases. For example, young shoots are often chlorotic when they emerge from the seed, but green up quickly provided they get sufficient light.

Interveinal chlorosis is sometimes indicative of iron, manganese or magnesium deficiency. This isn’t necessarily indicative of low levels of these microelements in the soil or growing medium but is sometimes caused by the plant’s inability to mobilise them quickly enough. In the case of magnesium deficiency, this can be remedied bus foliar feed. For example, tomatoes sometimes run out of magnesium when at the 5-6 truss stage and can sometimes benefit from a foliar feed .. Epsom salts are the usual ingredient for this feed which is sprayed on the leaves in the early evening or other time when strong sunlight is absent.

A lack of nitrogen is also a possible cause of yellowing or reddening of leaves, especially older leaves. where the second indicator is a lack of plant vigour characterised by slow growth.

Leaves also go chlorotic in the autumn as the plant withdraws valuable nutrients from the leaves before shedding them.


A soil component. Clay soils are composed of very fine granules and colloidal substances. this means they go hard and crack when dry and become very sticky when wet. This makes them a cold soil that is slow to warm up in spring and can bake hard in summer. The fact they can bake hard is why some calls are used to make bricks.

Clay soils are rich in nutrients and can range in colour from white or dull grey to orange or dark brown.

Most soils contain some clay and a small amount is beneficial. However, when it predominates it is a difficult soil to cultivate and grow crops in.


From the French for bell, a form of plant protection, the origianl ones were glass and made in the shape of a bell.

Today the range of cloches is much wider with continous plastic covered hoops that form a mini tunnel being available in many garden centres.

Recycled plastic bottles are often used as a form of plant cloche by many gardeners.


Plants that are produced asexually either as seed or via stem or root cuttings are clones of the parent plant. This means they have exactly the same genetic composition ie they are genetically identical.

Clones occur naturally in some species and are used as a means to reproduce. In some cases, they shed branches or twigs that can then root nearby. In other cases, they form clonal colonies. Elm trees are an example of reproduction by clonal colonies via suckering.

Dandelions are an example of a plant that is capable of a plant that can produce asexual seeds via a process called apomixis.


Some plants naturally form clumps rather than individual plants. They tend to be perennials.

Clump-forming vegetables include shallots and chives.

Complete Fertiliser

A fertiliser that contains all three of the major or micronutrients essential for plant growth, namely nitrogen, phosphorus and potassium. (N, P, K). Complete fertilisers are often referred to as General Purpose fertilisers.


Compost is composed of organic material that has decomposed in a process called composting. Compost sold in garden centres have usually been composted on an industrial scale though it is easy to compost smaller amounts of organic matter on a garden scale.

Peat is also composed of organic material but is not normally referred to as compost. Indeed many composts are sold as peat-free composts due to the negative conservation issues attached to peat use.

Compost is nutrient-rich and if made well is free from pest, disease and weeds due to the high temperatures achieved during the composting process.

Composts include seed composts, ericaceous composts, loam-based compost, peat-based compost, organic compost, peat-free compost, leaf compost, potting composts, multi-purpose compost etc. All of these have slightly different purposes and makeup including pH and fertilizer levels

Compost is used as a soil conditioner, fertiliser and growing medium.


Unlike deciduous trees, coniferous trees keep their leaves during winter. This means they have to grow more secure roots to ensure they don’t blow over in storms. 


A pot or other receptacle for growing plants

Controlled Release Fertiliser

A fertiliser that has been manufactured as a prill of in other form designed to release nutrients in response to temperature or moisture stimulus


Cordon grown fruit include tomatoes. The plant, in this case, is sideshooted to allow a single cordon to dominate the growth. Cordon systems are used in commercial horticulture as a form of vertical growing.


Cotyledons; of which there are two sorts, monocotyledons and dicotyledons, are used to refer to plant seed leaves. in a wider sense, they refer to the two groups of flowering plant types that are defined by the nature of their embryonic seed leaves.

Examples include grasses and cereals which are monocots and plants such as the Solanaceae and Cucurbitaceae .. the tomato, pepper and potato family and the cucumber, marrow, squash family which are dicots.


Corms are underground stems which are designed to produce leaves, roots, flowers and stems. Very few vegetables form corms, examples include eddoe and taro.

Cover crops

Cover crops are grown when main crops are not being grown. They decrease erosion and can be used to increase fertility when ploughed in. For example clover and other leguminous crops might be grown and dug in to increase fertility, especially nitrogen levels.

Cover crops may also be harvested for composting. this is of special interest when no-dig systems are employed.


Cultivar is short for cultivated variety and is commonly used to describe ornamental or decorative flowering plants.


A tool used to cultivate the soil

Cultivations – To Cultivate

Cultivations are the mechanical process of turning and or breaking the soil to produce a seedbed. The word is sometimes expanded to include intercrop/row cultivations that are used to weed between plant rows.

Cultivations break the soil crust allowing both soil aeration and improved drainage/water penetration.


One of a series of ways to propagate plants. In this case, propagation is achieved via root or stem cuttings. Sometimes a rooting hormone powder is used to speed the growth of roots from the stem. Stem cuttings include softwood, semi-hardwood and hardwood cuttings depending on the species, time of year etc.

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Gardening Terminology – D

Damping off

A fungal disorder whereby seedlings die due to the stem rotting off at soil level. Sometimes the seeds fail to germinate due to the same fungi. Prevention includes using sterile composts, good air circulation, clean water sources and ensuring the compost is not over watered. 


The process of removing dead flowers to encourage more flowering. Seed production produces hormones that discouraged more flowers. Hence if the flower heads are removed there is no seed produced and more flowers will usually follow. 


Deciduous trees and bushes are those that shed their leaves in autumn and do not regrow them until spring.  The process is determined by cells within the abscission layer of the leaf – see abscission layer.  This offers many benefits. Toxins that have built up in the lives are removed, the old leaves are then available for recycling back into the plant. In addition, the absence of leaves means that wind rock is reduced. If all the branches had a full contingent of leaves it would be badly affected by strong winds and storms and could be blown over.

Coniferous trees keep their leaves and need to anchor more strongly to the soil to ensure they are not blown over in storms. 

Dibber or Dibble stick 

Gardening Termnology - Dibber or dibble stick

A pointed stick or tool used to produce holes for plants. seeds or bulbs. 


A botanical term to describe plants that have male and female flowers on different plants. The female flowers are unable to be fertilised without a male plant being nearby to enable pollen transfer via insects, birds, wind or whatever mode is employed. 


Large clumps of perennials often benefit from being divided every 3-4 years in autumn or early spring. This entails splitting the clump into a number of plants each with roots, stems etc.  

Dormant / Dormancy 

Seed often exhibit dormancy at certain times of the year or until the right conditions are available. Eg. warmth, daylight etc. 

Plants also become dormant at certain times of the year e.g. after leaf fall in autumn. Though plants appear dormant it is often the case that they are producing root underground and cannot be said to be truly dormant. This is why autumn planting of bare root and pot-grown trees is often more successful, due to the fact they have made root over winter and have established. 


A straight narrow furrow in the soil or compost in which seeds are sown.

Sometimes used to denote the row in which plants can be transplanted.

See also Broadcast

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Gardening Terminology – E


Ericaceous refers to lime hating plants that therefore require an Acid Soil or compost. Hence we have ericaceous composts that have been designed for them.

Ericaceous plants include blueberries, heathers azalea, and rhododendron

Ericaceous Composts

Ericaceous Composts are designed with a high pH to grow ericaceous plants. Eg. camellias, azaleas, rhododendrons etc. This is particularly useful when growing in pots, planters and boxes and to a lesser extent in beds and borders. In the later care must be taken to ensure that the pH changes with rainwater incursion.


Soil erosion is caused by rain, wind, water flow and wind and can seriously deplete soils. Bare soils erode much faster than those with vegetation or other cover and hence many growers and farmers grow cover crops at certain times of year to decrease erosion.


A form of pruning trees and shrubs that produces lateral growth at teh expense of height. This makes fruit picking far easier. It also reduces competition between branches and increases air flow through the plant structure, often reducing diseases and improving ripening.

Etiolation & Etiolated

Gardening Terminology - Etiolation
An etiolated tomato plant

Etiolation is the technical word used when we say a plant is “drawn”. Etiolation in flowering plants happens when they are grown in poor, partial or complete absence of light. They respond with long, weak stems; smaller leaves due to longer internodes, and turn pale yellow in colour due to the lack of light (chlorosis). What we think is adequate light often isn’t enough for plants and they get very drawn in their search for better light.

Etiolation is the process of becoming etiolated.


The physical process by which liquid water returns to the air. It is speeded by higher temperatures and wind.

Evaporation is important in the process of transpiration.


Evergreen plants do exactly what their names suggest. They remain evergreen throughout the year, they do not shed their leaves. This is sometimes influenced by the climate and/or weather conditions.

Most, but not all, conifers are evergreen. Eg. the dawn redwood (Metasequoia glyptostroboides) is a deciduous conifer.


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Gardening Terminology – F


Plant food. Plants need a range of major, minor and trace nutrients to survive, grow and reproduce. The major ones are Nitrogen, Phosphates and Potassium that are usually represented as NPK. Minor and trace elements include magnesium, zinc, calcium, sulphur and iron.

Plant nutrients occur naturally in soils and composts but not always at a sufficiently high level to allow the required level of growth. Hence gardeners and growers need to add more fertiliser.

Where NoDig is employed the plant nutrients come from the compost added to the surface and this is generally done once or sometimes twice a year. In other cases fertiliser may need to be added before planting each crop. It is then sometimes topped up during the growth of the crop.

Fertiliser can be purchased as organic or inorganic (artificial) fertilizer and can be in liquid or solid form. In many cases it needs to be broken down in the soil by bacteria and dissolved in water before it is available to the plant.

Although the idea of being organic appeals to many people, the plants can’t tell the difference between organic and non-organic fertilisers as they are taken up by the plant in exactly the same way.

When growing commercially and now on a garden scale I’ve used Vitax Q4 as a granular base dressing fertiliser for general use and Tomorite as a liquid feed for tomatoes, peppers, courgettes, aubergines, cues etc.

I’m often asked about fertiliser. I use Vitax Q4 as a general purpose fertiliser. And Tomorite for tomatoes, cucumbers, aubergine, peppers and chillis.


Horticultural fleece is a thin, light woven material with high light transmission that can be used to cover crops. It reduces weather damage, keeping crops warmer and reduces pest damage by preventing access to butterflies, carrot fly etc.

Fleece comes on various weights, the heavier ones lasting longer. Fleece is permeable to air and rain.

To help prevent carrot fly you can cover the crop with fleece, which lets light, air and water in but keeps carrot fly out.


A plant’s leaves are it’s foliage.

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Gardening Terminology – G


The process where a seed starts to grow.

Green Manure

In conventional growing this is a crop grown to plough into the soil. In No Dig gardening the crop can be incorporated by smothering it under a black sheet or similar until it dies.

Green manures offer many benefits including the prevention of erosion, addition of organic matter, incorporation of nitrogen when leguminous crops such as clover are grown. In essence the aim is to increase soil fertility.

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Gardening Terminology – H

Hardening off

The process where plants become acclimatised to new conditions. It usually applies to plants grown indoors or under cover being moved outdoors but can also apply to plants being brought in from cold conditions to warm, dry conditions.

Hardening off is a slow process and best done in steps

Heavy soil

Heavy soils contain a lot of clay and are generally poorly drained and cold.


Though intensely studied humus is often ill defined. It is perhaps best defined as the amorphous product of degraded compost. Ie the dark spongy matter that is left when compost breaks down and no longer has a well defined composition. It includes animal, plant and microbial remains that have been mechanically degraded but retain their chemical composition.

Humus is an important part of soil organic matter and important as a moisture reservoir.

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Gardening Terminology – I

Integrated Pest Management (IPM)

IPM is widely used in agriculture and commercial horticulture, and can be employed in gardening as well. It uses a wide array of methods to combat pest and diseases including cultural practices, natural predators and parasites, pest/disease resistant varieties, pesticides (if all else fails), biological control and physical techniques such as fleece etc.

IPM is not organic but tries to minimise the use of pesticides wherever possible.

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Gardening Terminology – J

Gardening Terminology  – Back to Top

Gardening Terminology – K


The chemical symbol for Potash,a major plant nutrient and fertilizer component.

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Gardening Terminology – L

Land Classification

In the UK land is divided into five major classes, from class 1-5. Class one is the best land, very fertile, able to grow the best crops and is the most expensive. It is predominantly found in river valleys and in the predominantly vegetable growing areas of Lincolnshire. They are usually alluvial soils, predominantly silts. The other class one lands are peat-based. In both cases, they must be well-drained and not prone to flooding or they would not be regarded as class one.

Class 5 is very poor land, unfit for growing agricultural crops, often flood prone.

Class 3 land is subdivided into several subsets and is “average” land with various characteristics.


A propagation method where a low hanging branch or shoot is secured in the soil, whilst still attached to the parent plant, until it forms roots and is able to be detached from the parent plant.

Leaf compost or Leafmould

Leaves take a long time to compost but make an excellent rich compost that is dark and earthy. It i very moisture retentive and is an excellent addition to other composts where moisture retention needs to be improved.

To make leaf mould leaves should be collected in autumn and held in a compost bin constructed of chicken wire. Alternatively some people suggest you collect the leaves with a lawn mower as this shreds them, add them to a large plastic bag, wet them thoroughly, tie the bag neck , piece the bag for drainage and leave for two years.

I find both methods work. However teh former works quicker if you turn the leaves a few times to aerate the heap.


Loam is a mix of predominantly sand and a smaller quantity of clay particles along with other soil particles. The proportion of sand to clay subdivides loams into sandy loam, silty loam, sandy clay loam, silty clay loam and clay loam.

Loam-based Compost

Loam-based composts have a percentage of loam added to them. This makes them heavier, hence less likely for pots to blow over, and less likely exhibit rapid temperature fluctuations.

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Gardening Terminology – M


Minor plant nutrient. Where plants suffer a deficiency it can be remedied by a foliar feed containing epsom salts.


Organic material from the farmyard. The droppings of farm animals, normally mixed with straw of other bedding materials.

See also Green manure.


An organic layer of material that is spread over the surface of the soil, between the plants, to control weeds, hold in moisture and, in most cases, to improve fertility. Materials used include compost, spent mushroom compost, woodchip, straw, leaves, leaf mould, grass mowings, etc.

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Gardening Terminology – N


Nitrogen is a major plant nutrient required for growth, especially of green material such as stems and leaves. It occurs naturally in the air and at low levels is dissolved in rain. Leguminous crops produce nitrogen in association with nitrogen-fixing bacteria in root nodules. The nitrogen is available to the leguminous plant eg clovers, beans, peas etc. when it is growing and is released and made available to other plants when the leguminous plant dies.

No Dig Gardening

A gardening technique that involved no digging or ploughing of the soil. A mulch is added to the soil surface which suppresses weeds and feeds the soil and hence plants. Plants are sown direct or, preferably planted by using plant plugs/modules and a dibber.

No Dig has much to commend it, especially reduction in labour and effort to prepare the soil, and elimination/suppression of weeds.

In the first year many practitioners lay cardboard on the soil surface and then add mulch as this further inhibits weeds in the first season.

No Till Gardening

See No Dig Gardening

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Gardening Terminology – O


The organic gardening movement is exemplified in the UK by Garden Organic, the Coventry based charity previously known as the Henry Doubleday Research Association (HDRA).

Garden Organic and similar organisations believe that crops should be grown organically, without the use of pesticides, artificial fertilisers etc whilst embracing natural growing cycles to enhance growth and the environment.

Organic Compost

Because it is made from degraded organic matter people often think that all composts are organic. However the vegetable matter the compost was made from is rarely organic in the Soil Association sense of the word. In addition various chemicals maybe be added as fertilisers.

Soil Association certified organic composts are available from specialist producers.

Organic Matter

Organic matter is a carbon based material composed or the remains of plants and animals and their waste products.

The organic matter in soils is derived from degraded plant and animal material plus microorganisms. Organic matter is desirable as it retains moisture and essential plant nutrients.

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Gardening Terminology – P


Partially decomposed vegetable matter produced in bogs, fens and other acidic wet environments.

Until recently peat was commonly dug, dried and sold as a compost for growing plants. Digging peat destroys rare habitats and is now largely stopped after environmentalists highlighted the problem.

Peat soils are farmed in areas such as the Fens of England and are extremely productive.

Some soils have a mix of peat in their composition, usually where a thin layer of peat has been mixed with other soil types as they have been farmed over centuries.

Peat-based Compost

Peat-based compost is less common these days due to environmental concerns. At one stage it was the most common compost available to commercial and amateur growers.

Peat-free Compost

Peat-free compost is available from many sources as are reduced peat mixtures. Peat free was problematic when first introduced as it suffered poor drainage and variable quality. That is now largely a thing of the past.

If the pack doesn’t specifically say peat free it is highly likely to contain some peat.


Perennials are long-lasting and may seed many times during their lifetime. Trees are a prime example, think how many acorns an oak will produce in a lifetime that spans centuries. So fruit trees, fruit bushes and even strawberries are perennial. But we aren’t limited to fruit. Perennial kale and asparagus have long lifetimes and keep producing fruit, leaves etc.

Phosphorus / Phosphates

Phosphorus is a major plant nutrient that normally occurs as a phosphate. It is essential for healthy plant growth including the production of oils, starch and strong root systems.


Aerial roots that are used to obtain oxygen from the air when underground roots become waterlogged. Frequently found on mangroves, banyans there are sometimes apparent on schleffera, ficus benjamina and rarely on brassicas and tomatoes.


Potassium is one of the three major plant nutrients and has a role in producing flowers and fruit, fight off disease, produce proteins and aid in photosynthesis

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Gardening Terminology – Q

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Gardening Terminology – R

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Gardening Terminology – S


Sand is one of the coarser constituents of the soil and those soils with more than 85% of material calssified as sand are referred to as sandy soils.

Sand is derived from rocks that have been broken down by rain, frost, wind etc. Sands composition depends on the rock from which it is derived but is largely silica-based. However, the second most common constituent of sand is calcium carbonate, which is typical of those sands derived from corals and seashells.

Seed Compost

Seed compost is produced for the sole purpose of germinating and growing on seedlings. It is usually open and free draining with a pH around neutral. Other than lower levels of nutrients the compost can contain peat or be peat-free.


Silt, an important soil constituent, is the granular non-organic material that is sized between sand and clay.


Soil is a complex mixture of rock particles ranging in size from sand to clay; minerals, stones, organic matter, chalk, peat, gases, liquids, humus, soil organisms and empty spaces, that is found on the surface of the planet.

Soil is normally recognised as having four distinct functions:-

  • A growing medium for plants of all descriptions.
  • A medium which retains gases, such as CO2, in various forms and hence modifies the earth’s atmosphere.
  • A habitat for soil organisms
  • The filtration, purification, storage and supply of water.

The study of soil in its natural environment is called pedology and there is a range of soil types defined below.

Soil types

Soil is generally classified into loams, clays, silts, sands, peats and chalks.

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Gardening Terminology – T


To grow and survive plants rely on water moving from roots to the other parts of the plant. Transpiration is the process of water movement and subsequent evaporation of water from the plant parts designed for this.

Only a small amount of water taken up by the roots is used for metabolism and growth, the remainder is voided through the stomata and evaporates.

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Gardening Terminology – U


A botanical word meaning a cluster of flowers where the stalks spring from a common centre, are of similar length and result in a flat or slightly convex surface. An example would be the carrot flower.

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Gardening Terminology – V

Vertical Growing

Vertical growing is where the plants grow, or are arranged, vetically.

At a basic level this includes cordon and espalier fruit such as tomatoes, cucumbers and runner beans to apples and pears.

Vertical growing also includes where a series of pots or containers are stacked above one another in a vertical plane. Eg using pot holders affixed to a wall.

Vertical growing can also include green walls etc. This is usually achieved using hydroponics.

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Gardening Terminology – W

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Gardening Terminology – X

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Gardening Terminology – Y

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Gardening Terminology – Z

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