The nature of horticulture

Horticulture may be described as the practice of growing plants in a relatively intensive manner. This contrasts with agriculture, which, in most Western European countries, relies on a high level of machinery use over an extensive area of land, consequently involving few people in the production process. The boundary between the two is far from clear, especially when considering large-scale outdoor production. When vegetables, fruit and flowers are grown on a smaller scale, especially in gardens or market gardens, the difference is clearer cut and is characterized by a large labour input and the grower's use of technical manipulation of plant material. Protected culture is the more extreme form of this where the plants are grown under protective materials or in glasshouses.

There is a fundamental difference between production horticulture and service horticulture which is the development and upkeep of gardens and landscape for their amenity, cultural and recreational values. Increasingly horticulture can be seen to be involved with social well-being and welfare through the impact of plants for human physical and mental health. It encompasses environmental protection and conservation through large- and small-scale landscape design and management. The horticulturists involved will be engaged in plant selection, establishment and maintenance; many will be involved in aspects of garden planning such as surveying and design.

There may be some dispute about whether countryside management belongs within horticulture, dealing as it does with the upkeep and ecology of large semi-wild habitats. In a different way, the use of alternative materials to turf as seen on all-weather sports surfaces tests what is meant by the term horticulture.

This book concerns itself with the principles underlying the growing of plants in the following sectors of horticulture:

  • Outdoor production of vegetables, fruit and/or flowers (see p5).
  • Protected cropping, which enables plant material to be supplied outside its normal season and to ensure high quality, e.g. chrysanthemums, all the year round, tomatoes to a high specification over an extended season, and cucumbers from an area where the climate is not otherwise suitable. Plant propagation, providing seedlings and cuttings, serves outdoor growing as well as the glasshouse industry. Protected culture using low or walk-in polythene covered tunnels is increasingly important in the production of vegetables, salads, bedding plants and flowers.
  • Nursery stock is concerned with the production of soil- or container-grown shrubs and trees. Young stock of fruit may also be established by this sector for sale to fruit growers: soft fruit (strawberries, etc.), cane fruit (raspberries, etc.) and top fruit (apples, pears, etc.).
  • Landscaping, garden construction and maintenance that involve the skills of construction together with the development of planted areas (soft landscaping). Closely associated with this sector is grounds maintenance, the maintenance of trees and woodlands (arboriculture and tree surgery), specialist features within the garden such as walls and patios (hard landscaping) and the use of water (aquatic gardening).
  • Interior landscaping is the provision of semi-permanent plant arrangements inside conservatories, offices and many public buildings, and involves the skills of careful plant selection and maintenance.
  • Turf culture includes decorative lawns and sports surfaces for football, cricket, golf, etc.
  • Professional gardening covers the growing of plants in gardens including both public and private gardens and may reflect many aspects of the areas of horticulture described. It often embraces both the decorative and productive aspects of horticulture.
  • Garden centres provide plants for sale to the public, which involves handling plants, maintaining them and providing horticultural advice. A few have some production on site, but stock is usually bought in.

The plant

There is a feature common to all the above aspects of horticulture; the grower or gardener benefits from knowing about the factors that may increase or decrease the plant's growth and development. The main aim of this book is to provide an understanding of how these factors contribute to the ideal performance of the plant in particular circumstances. In most cases this will mean optimum growth, e.g. lettuce, where a fast turnover of the crop with once over harvesting that grades out well is required. However, the aim may equally be restricted growth, as in the production of dwarf chrysanthemum pot plants. The main factors to be considered are summarized in Figure 1.2, which shows where in this book each aspect is discussed.

In all growing it is essential to have a clear idea of what is required so that all factors can be addressed to achieve the aim. This is what makes market research so essential in commercial horticulture; once it is known what is required in the market place then the choice of crop, cultivar, fertilizer regime, etc., can be made to produce it accurately.

It must be stressed that the incorrect functioning of any one factor may result in undesirable plant performance. It should also be understood that factors such as the soil conditions, which affect the underground parts of the plant, are just as important as those such as light, which affect the aerial parts. The nature of soil is dealt with in Chapter 17. Increasingly, plants are grown in alternatives to soil such as peat, bark, composted waste and inert materials which are reviewed in Chapter 22.

To manage plants effectively it is important to have a clear idea of what a healthy plant is like at all stages of its life. The appearance of abnormalities can then be identified at the earliest opportunity and

Microclimate Chapter 2

Harmful substances Chapters 8, 15 and 16

Light Chapters 2 and 8

Soil orgs Chapters 14, 16 a

Chapters 14 an<

pH and Nu Chapters 20 ;

Chapters 15

Microclimate Chapter 2

Harmful substances Chapters 8, 15 and 16

Light Chapters 2 and 8

Soil orgs Chapters 14, 16 a

Chapters 14 an<

pH and Nu Chapters 20 ;

Chapters 15

Weeds

Chapters 13 and 16

Temperature Chapters 2, 8 and 16

Water

Chapters 2, 9 and 19

Growing media Chapters 17 and 22

Oxygen

Figure 1.2 The requirements of the plant for healthy growth and development m/ Chapters 8, 10, 12, 13 and 22 /■ Seeds Chapter 7

Weeds

Chapters 13 and 16

Temperature Chapters 2, 8 and 16

Water

Chapters 2, 9 and 19

Growing media Chapters 17 and 22

Oxygen

Figure 1.2 The requirements of the plant for healthy growth and development appropriate action taken. This is straightforward for most plants, but it is essential to be aware of those which have peculiarities such as those whose healthy leaves are not normally green (variegated, purple, etc., see p82), dwarf forms, or those with contorted stems e.g. Salix babylonica var. pekinensis 'tortuosa'. The unhealthiness of plants is usually caused by pests (see Chapter 14) or disease (see Chapter 15). It should be noted that physiological disorders account for many of the symptoms of unhealthy growth which includes nutrient deficiencies or imbalance (see p127). Toxics in the growing medium (such as uncomposted bark, see p388) or excess of a nutrient (see p370) can present problems. Damage may also be attributable to environmental conditions such as frost, high and low temperatures, high wind (especially if laden with salt), a lack or excess of light (see p113) or water (see p122). Further details are given in Chapter 15.

Weather plays an important part in horticulture generally. It is not surprising that those involved in growing plants have such a keen interest in weather forecasting because of the direct effect of temperature, water and light on the growth of plants. Many growers will also wish to know whether the conditions are suitable for working in. Climate is dealt with in Chapter 2, which also pays particular attention to the microclimate (the environment the plant actually experiences).

A single plant growing in isolation with no competition is as unusual in horticulture as it is in nature. However, specimen plants such as leeks, marrows and potatoes, lovingly reared by enthusiasts looking for prizes in local shows, grow to enormous sizes when freed from competition. In landscaping, specimen plants are placed away from the influence of others, so that they not only stand out and act as a focal point, but also can attain perfection of form. A pot plant such as a fuchsia is isolated in its container, but the influence of other plants, and the consequent effect on its growth, depend on spacing. Generally, plants are to be found in groups, or communities (see Chapter 3).

Homeowners Guide To Landscaping

Homeowners Guide To Landscaping

How would you like to save a ton of money and increase the value of your home by as much as thirty percent! If your homes landscape is designed properly it will be a source of enjoyment for your entire family, it will enhance your community and add to the resale value of your property. Landscape design involves much more than placing trees, shrubs and other plants on the property. It is an art which deals with conscious arrangement or organization of outdoor space for human satisfaction and enjoyment.

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