Mulching and Watering Vegetable Plants
Mulching and watering
Soil is a natural reservoir. The more thoroughly it is cultivated, and the more decayed organic material (called humus) it contains, the greater its capacity to store water.
Apart from surplus rainwater which drains away, soil loses moisture in two ways: by direct evaporation from the surface, and through the action of plants, which take up water in their roots and transpire it through their leaves.
In hot, dry spells the moisture content of soil needs to be supplemented by watering, but it can also be conserved by mulching — that is, by placing a barrier between moisture-holding soil and the air. A mulch can be a layer of peat, polythene, garden compost or well-rotted manure.
Frequent hoeing is also of benefit. Without hoeing, and especially if trodden and compacted when wet, the surface remains dark in colour and may feel moist during dry weather. This is because moisture is being drawn to the surface, where it will be lost by evaporation. Later, the surface will bake hard and crack, increasing the loss of moisture.
This is less likely to happen if you hoe regularly, leaving a fine, surface up to 1in (25 mm) deep.
The beneficial effect of hoeing can be increased by adding another moisture-retaining layer — peat, garden compost or manure — along both sides of rows of crops to a depth of 2-3in (50-75 mm) .
Mulch soft-fruit bushes and canes in April while the soil is still moist. Begin mulching annual crops of vegetables when they are a few inches high. If the ground is dry, water thoroughly before applying the mulch.
Mulches of organic material, such as manure or compost, are valuable because they ultimately add to the humus content of the soil. But black polythene makes an effective mulch for some crops —especially for strawberries and bush tomatoes, as it prevents the fruits resting on the soil.
Before laying polythene, ensure that the soil is moist and scatter slug pellets along each side of the row. Cover each edge of the polythene with soil to keep the sheets in position.
You can lay separate strips about 12in (305 mm) wide on each side of a row of plants, or cut slits in a broader sheet to match the positions of plants.
When using a hose or can, water the ground thoroughly, giving at least 5 gallons per square yard (23L per square metre). If you give too little, water will not reach the roots even though the top layer appears wet. If you continue to apply small amounts, the roots may be drawn up to the moist surface and will suffer even more if this dries out.
Some plants — for example, cucumbers, marrows, melons, pumpkins, runner beans and tomatoes are gross drinkers. They show distress very quickly if they do not have sufficient moisture.
Regular watering is essential during long, dry spells. Spasmodic watering can cause poor setting of the flowers of some crops and ripening fruits may split.
Water in the evening so that the plants get the benefit during the night. Water applied early on hot, sunny days will evaporate before it can reach the roots.