Watering vegetables and fruit

The key to watering successfully is to water thoroughly but not too often. Avoid just regularly wetting the top centimetre or so.  

Dig down to a spade’s depth to see and feel if there is moisture in the soil. If the soil is dry, water thoroughly to the depth of the crop’s root zone. Bear in mind that soil type will determine how water is held in the soil. Use our soil types guide to discover what kind of soil you have and how it holds moisture.

Vegetables need varying amounts of water depending on their stage of growth, the type of plant and the type of soil. For a general guide, the following may help:

• Freshly sown seed and young vegetable plants need consistent moisture. Water the seed drill
  

  A miniature furrow typically 1–5cm deep, made with a stick, hoe or rake. It is used for planting seeds or bulbs, and ensures they are positioned at the correct depth and spacing.

  before sowing
• Once plants are established and putting on growth, to keep watering to a minimum, water when drought will affect the part of the plant that is to be harvested

Water seed drills before sowing to ensure moisture is at the depth where the seed needs it

The amount of water needed by the crop depends on which part of the plant is eaten. Ideally, crops like lettuce, potatoes and cauliflowers should never suffer drought stress, but where it is not possible to water them thoroughly, watering at the rosette stage for lettuces and cauliflowers, and when potato tubers are forming – just before flowering, gives good results for relatively little water.

Legumes

Broad beans and peas need plenty of water at flowering time for pods to set, and again two weeks after flowering begins. As young plants, avoid too much water as this can encourage leafy growth and reduce the yield. Runner beans need constant moisture for pods to set, whereas French beans are less sensitive to some dryness.

Climbing French beans require less water than runner beans

Stem vegetables

Celery, celeriac and Florence fennel need water during growth. Periods of drought stress are very damaging and should be avoided, as this can lead to bolting

When a vegetable plant starts flowering and forming seeds, often prematurely, making the crop unusable – salad leaves may turn bitter and root crops fail to swell. Adverse weather or changes in day length can cause bolting in a wide range of vegetables, including lettuces, onions, carrots and other root crops.

or poor-quality crops.

Cucurbits

Courgettes need constant moisture all the way through to harvest. Marrows, pumpkins and winter squash benefit from watering but, in practice, often produce reasonable yields from minimal watering. Trailing types need less water as their spreading habit conserves moisture and the stems root where they touch the ground.

Fruiting crops

Aubergines, sweetcorn and tomatoes all need watering thoroughly to aid establishment. They also benefit from consistent watering throughout the flowering and fruiting period.

Leafy crops

Cabbages, chard, lettuce and other leafy salad crops need water at every stage of growth. If water is especially short, make sure that you soak the ground around cabbages and lettuces when hearts begin to form.

Root crops

• Carrots, beetroot and parsnips require watering before the soil becomes dry, for example, if there are 14 days without rain
• Onions, shallots and leeks only need to be watered when they are establishing, and in very dry spells
• Potatoes benefit from being watered every 10–14 days once the tubers are marble size
• Radishes need to be watered every week in dry spells

Fruit trees

• Water young fruit trees during dry spells in the first three or four growing seasons after planting. If they become stressed, this can cause stunted growth, a weakened root system and a higher susceptibility to pests and diseases
• Established trees should only need watering during prolonged dry spells. Fruit trees that experience drought stress are likely to produce fewer and smaller fruits
• You will know if your apples suffered from drought if the fruits have bitter pit or watercore
• Reduce competition by keeping a vegetation‑free tree circle at least 1 m (3⅓ ft) in diameter around the trunk. Ideally, mulch
  

  Mulch is a layer of material, at least 5cm (2in) thick, applied to the soil surface in late autumn to late winter (Nov-Feb). It is used to provide frost protection, improve plant growth by adding nutrients or increasing organic matter content, reducing water loss from the soil, for decorative purposes and suppressing weeds. Examples include well-rotted garden compost and manure, chipped bark, gravel, grit and slate chippings.

  around the tree annually with organic matter such as homemade compost
  

  Can refer to either home-made garden compost or seed/potting compost:

  
  • Garden compost is a soil improver made from decomposed plant waste, usually in a compost bin or heap. It is added to soil to improve its fertility, structure and water-holding capacity. Seed or potting composts are used for growing seedlings or plants in containers - a wide range of commercially produced peat-free composts are available, made from a mix of various ingredients, such as loam, composted bark, coir and sand, although you can mix your own.

  
  

Soft fruit 

• Keep berries such as strawberries, blueberries and raspberries well-watered through flowering, fruit set, development and through to harvest
• Currants and gooseberries dislike dry conditions but are not as badly affected as strawberries, blueberries and raspberries
  

In containers

From spring through to autumn, check that the compost is still damp where the roots are. You may need to water every day in dry spells. See our guide to watering containers.

Watering plants is time consuming but with a little planning, you can water less and enjoy more time picking and eating your produce.  

No-dig gardening  

A no-dig approach can significantly reduce how often plants need watering. Digging soil exposes moist layers to air, allowing water to evaporate more quickly. It can also break up soil structure and the beneficial soil life that help plants access water.

• No-dig helps retain moisture by restricting soil disturbance to hoeing
  

  Hoes are multi-purpose tools for weeding (especially between rows of veg), loosening the soil surface, making seed drills, earthing up plants, and more. There are various types with different shaped blades. Hoeing to remove weeds is best done on a warm, dry day, so you slice easily through weed stems just below the surface.

  , planting and harvesting
• Undisturbed soils allow roots and soil organisms to form stable networks that improve water uptake
• Adding organic matter to the surface, rather than digging it in, protects soil structure and reduces water loss
• After mulching the soil, you can sow or plant directly into the mulch
  

  Mulch is a layer of material, at least 5cm (2in) thick, applied to the soil surface in late autumn to late winter (Nov-Feb). It is used to provide frost protection, improve plant growth by adding nutrients or increasing organic matter content, reducing water loss from the soil, for decorative purposes and suppressing weeds. Examples include well-rotted garden compost and manure, chipped bark, gravel, grit and slate chippings.

Other techniques to reduce water use:

• To create new fruit and veg growing areas, add plenty of organic matter. Garden compost, well-rotted manure and green waste
  

  Plant-based waste that is suitable for composting, such as dead leaves, clippings from pruning or grass mowing and discarded annuals. Many local councils have green waste recycling schemes if home composting isn't an option.

  compost
  

  Can refer to either home-made garden compost or seed/potting compost:

  
  • Garden compost is a soil improver made from decomposed plant waste, usually in a compost bin or heap. It is added to soil to improve its fertility, structure and water-holding capacity. Seed or potting composts are used for growing seedlings or plants in containers - a wide range of commercially produced peat-free composts are available, made from a mix of various ingredients, such as loam, composted bark, coir and sand, although you can mix your own.

  are all useful
• When planting fruit trees or shrubs, if your soil is poor, mix a bucketful of organic matter into the soil you remove from the planting hole and use this to backfill after planting. This minimises soil disturbance and helps the plant get off to a strong start
• Mulch under crops after watering or rainfall with a 5–7.5cm (2–3in) layer of organic matter. Mulching will improve your soil, help to retain moisture and suppress weeds
• Keep vegetable-growing areas free of weeds. A surprising amount of moisture can be taken from the soil by weeds
• Plant through a layer of biodegradable
  

  Anything that can be decomposed by fungi, bacteria and micro-organisms, so it doesn’t persist indefinitely in the environment. Biodegradable plastics are usually made from plants, such as bamboo, rather than fossil fuels. Ideally, products that claim to be biodegradable should break down quickly and leave nothing harmful behind. However, they may need specific conditions in order to biodegrade successfully or may produce greenhouse gases such as methane in the process.

  fabric, such as jute or hessian matting, to conserve water and control weeds. Onions, garlic and leeks generally do not cope well with competition from weeds. If you grow potatoes this way, they do not need earthing up
  

  Mounding soil up around plants, usually specific vegetable crops. With potato plants, it protects early shoots from frost and ensures new tubers aren’t exposed to light, which can make them green and poisonous. With tall or top-heavy plants such as brassicas, it helps to prevent windrock, which can loosen the roots. Leeks and celery are earthed up to blanch the stems.

• If you plan to set up irrigation, such as leaky pipes or drip lines, place it underneath the fabric
• On very dry soils, plant transplants a little lower than the surrounding soil so that water collects in the ‘puddle’ and sinks in
• Collect rainwater in water butts to reduce the need to use mains water. For more information, see our guide to collecting, storing and reusing water

• The growth of the plant will increase, but not necessarily the edible portion. For example, peas watered before flowering make more leafy growth but not proportionally more pods
• Blossom end rot can affect tomatoes and related crops, such as aubergines and peppers, when watering has been inconsistent
• Too much water can cause root vegetables such as carrots to split
• Overwatering can exacerbate slug and snail problems and encourage rotting of roots and lower sections of stems

Be aware that you need to have a double check valve on all outside taps to meet water regulations. The valve is designed to prevent any contamination flowing back into the mains supply.

For permanent, automated garden irrigation systems connected to the mains, a break tank providing an air gap is often a regulatory necessity to ensure the safety of the public water supply.