Regular watering and sensible irrigation is essential to the development of any plant, it is crucial for healthy growth and successful fruiting. Water is drawn from the root of the plant and transported through its capillary system, transferring valuable nutrients collected from the soil and eventually released through the plant foliage by evaporation and transpiration. This water needs to be replaced in order to sustain steady growth. The moisture content of the soil or compost must be maintained for this to happen, taking into account losses due to surface run-off, drainage and evaporation.
Overwatering can cause problems with your plants, affecting their ability to process oxygen and carbon dioxide, and may suffer from root damage and fungal growth. Excess water also encourages slug and snail activity. Water requirements vary between plant species and will change during the different stages of plant development, gardeners will only know if demands are being met by checking beds regularly. The needs of outdoor plants are dictated by the weather with water availability being affected by wind, rain and temperature. Plants grown in polytunnels or greenhouses cannot rely on rainfall therefore a strict regime, adjusted throughout the growing season, needs to be in place to accommodate plant demand and temperature fluctuations. Steady or phased watering is important to prevent irregular growth, impaired fruit development or excess foliage.
A wide range of irrigation systems and equipment are available to ensure the varying needs of a vegetable garden are provided for, from rainwater harvesting to sprinklers and dripper hoses.
Hoses, Connectors and Nozzles. Hoses are vital in transporting water around the garden, from water butts and taps to beds and greenhouses. It is possible to build a complete irrigation network using sections of hose and incorporating timers, manifolds, drippers and soakers.
Sprays and Sprinklers. Lawns and larger beds can be watered by installing sprayers or sprinklers connected through a network of tubing. Spray systems deliver a fine mist whereas sprinklers cover a wider area with larger droplets which are less prone to evaporation.
Timer Systems. Mechanical or electrical timers can be used to control watering in a vegetable bed. This is ideal for periods when you are away from the garden but most systems will not take into account ambient temperature and changeable weather conditions.
Soaker Hoses. Polytunnels will require constant watering to maintain the correct environment for vegetable cultivation. Soaker hoses laid upon the surface of the soil and covered with shallow mulch can provide a steady, regulated water flow, compensating for temperature fluctuations. They are made from a continuous porous material and provide a constant delivery, best used in conjunction with a timer or manual intervention to prevent overwatering.
Drippers. Plastic tubing is buried into the soil with small emitters placed near the plant roots for direct, targeted watering. The water is efficiently used with this method, avoiding the risk of flooding and overwatering. The supply can be regulated to water the plants when only necessary. Like soaker hoses the dripper systems prevent foliage becoming wet which could lead to mildew and fungal problems.
Wicking and Capillary Watering. Using the natural phenomena of capillary action, wicking systems provide a self-watering supply. Capillary matting allows water to be drawn from a tray as and when the plant requires, avoiding problems with overwatering and water deprivation. Individual wicks can be linked to a hose supply to service each plant’s specific demands. This system works well with container gardens and with some adaptation it can be incorporated into larger beds.
Rainwater Harvesting. Rainwater is naturally soft, without any of the additives of mains water. It contains soluble nitrates, perfect for feeding growing vegetables and has a balanced pH of 6.5. It is a free resource, without any cost to the environment or your water supplier. Collect it from your roof guttering system using adapter kits and store in tanks or water butts covered to prevent the build up of algae.
Watering Can. This time honoured method provides the opportunity to engage with your garden at first hand and take advantage of the therapeutic benefits of pottering about. Hand watering is still the best method for feeding and for targeting individual plants that need special attention.
When watering always concentrate on the root of the plant, where absorption and nutrient uptake happens. Excess water on the plant foliage is unnecessary and will promote disease. Good mulch is crucial in retaining moisture, preventing evaporation and deterring wasteful water run-off. Always prevent the soil surface from drying out and developing a crust which will affect absorption.
There a few rules on when to water, it is generally dependent on weather, soil condition and plant demand. Regular inspections of your garden will give you a better idea of when and how to water, poke a finger into the bed and if comes out wet your soil is moist enough. You should always adjust your timers or watering regime to provide a regular, steady water supply while taking into consideration the prevalent conditions.