You need to know how much you must water your plants and the right way to irrigate them, or you’ll waste water and have poor results with your vegetables, especially carrots. These need a good weekly soaking rather than light irrigations, which make them short and stumpy.
Rushing through the vegetable garden with a handheld hosepipe after work and giving the plants a quick watering isn’t the way to irrigate. There will be puddles and compacting, and not enough water will get under the surface of the soil.
The right way to water is to aim for the root zone. Most roots are found at a depth of 25cm to 30cm. The rule of thumb is to apply 25mm to 30mm of water to wet down to this depth, with more needed for clay and less for sand. In other words, 1mm of water will wet about 1cm of soil.
To see if the soil is receiving the right amount of water, dig down with a spade to a depth of about 25cm.
You’ll be surprised to see how dry the soil is, especially if you’ve been using a handheld hose!
Another good general rule is to water weekly, although you might have to water more often, depending on the amount of foliage. And watch out for those dry spells that can occur even during the rainy season. Also, gardeners in winter rainfall areas of the country should take extra precautions with their plants during the heat of summer.
- Always make sure the vegetable garden is moist at the beginning of the day when you’re in the middle of a heat wave.
- Avoid watering with a sprinkler on a windy day – you’ll lose about 40% of the water.
- The best time to water is early morning or late afternoon. Most of the water will evaporate if you water during the heat of the day.
- Sensitive crops like lettuce can (if wilted) suffer shock when irrigated during the heat of a very hot day.
- Give vegetables like potatoes (which have a restricted root system and a high consumption) additional water with a hose along the row rather than irrigating the whole area unnecessarily.