Water, Water Everywhere
From seed germination to harvest, water is absolutely essential for plant growth. It is, however, an increasingly scarce and expensive resource, and gardeners have a duty to manage it carefully.
Up in the air
Water in the garden is subject to a dynamic cycle of loss and renewal. In plants, for example, it continuously evaporates from the surfaces of the leaves. Foraging roots, however, compensate for this loss by taking in soil water, which then works its way up to the leaves. And so it goes.
Soils are store houses of water that are continuously being depleted, not just by growing plants but also by evaporation directly into the air. Given this state of affairs, the soils would eventually run out if they weren’t periodically replenished by rainfall or irrigation water.
Evaporation is an on-going process that reaches its peak on a hot, sunny summer’s day when the soil is moist and the wind is blowing. To combat water losses, frugal gardeners must go on the offensive and initiate preemptive strikes before the plants suffer (see below).
Tactics for reducing soil losses
- Decrease the crop population so that there are fewer plants competing for the same amount of water
- Control weeds when they are young
- Locate the garden in a sheltered spot to protect it from the wind
- Establish wind breaks
- Work in green manures, compost and well-rotted manure to increase the soil’s water-holding capacity
- Mulch the soil to reduce evaporation from its surface
- Sub-soil or, in smaller gardens, deep dig the soil to increase the crop’s rooting depth
Controlling weeds when they are young in a Chinese cabbage var. Apex crop.
Using black plastic as a mulch to reduce water loss in a greenhouse.
Time to water
Given the uncertainty of the British weather, there will be times when there just isn’t enough rainfall, and even the thriftiest of gardeners will have to water. One of the most critical times for moisture is during crop establishment, and recently-sown seeds, newly-germinated seedlings and just-transplanted plants should never be allowed to dry out.
A critical time for consciencious watering is recently sown seeds and newly germinated seedlings. Above: sowing Chinese cabbage var. Apex seed and just emered Apex seedlings.
Transplants must be kept well watered. Above: a transplant of Mizuna var. Broadleaved, a bed of newly transplanted oriental leaves.
As a general rule, established plants should be watered heavily every once in a while rather than lightly all the time. Plants, however, are created differently and do not necessarily accept general rules. Leafy crops like spinach and cabbage, for example, respond to regular watering throughout their lives. In contrast, peas and beans prefer less water before they flower, and more in the flowering to pod-swelling stage of their development. Similarly, root crops need more water when their roots begin to swell.
Different vegetable types have different water requirements: above chard var. Bright lights – leafy vegetables respond to regular watering throughout its life; pea var Carouby de Mausanne – peas and beans need more water during hte flowering and pod-swelling stage.
Watering established plants with sprinklers is a hit-or-miss affair that can be wasteful and ineffective – water is often blown around a windy garden or evaporates even before it hits ground. In a drive for efficiency, water should always be applied to the soil just above the plants’ roots, where it can do the most good.
Using a sprinkler to water the garden or vegetables is quite wasteful.
In small gardens, watering cans and hoes pipes can be fitted with attachments that deliver water directly to the plants.
Using a hand-held hose pipe and a watering can to water crops.
A higher tech option for both small and large gardens is a drip irrigation system consisting of black plastic tubing fitted with miniature nozzles. Water slowly drips from the nozzles and goes straight into the soil. The nozzles can be placed next to the plants, and, to reduce water losses even more, the whole irrigation system can go under a mulch.
Using a drip irrigation system. Above: water droplets slowly dripping from the nozzles; a crop of French beans var. Cobra watered with a drip irriagation system.
A cucumber plant var. Passandra with a drip irrigation pipe under black plastic to reduce water loss.
Alternatively, porous hose pipes purportedly made from recycled tyres can be laid directly on the soil near the plants. Nozzles are not necessary since water oozes out of the entire length of the pipe.
Water oozes out of the entire length of seap hosepipes.
© Sea Spring Seeds