OK, I’ll admit it, I’m a bit of a data nerd. Since so much gardening advice is based not on systematically tested ideas, but on received wisdom, I find that doing a little measuring and recording can often reveal some surprising results. One of the easiest methods I’ve found is to determine how much time I’ve spent doing various indoor and outdoor gardening tasks and noting how they stack up. While I was pretty sure that watering would be better in terms of time investment in the growing season, even I was surprised that 70% of my time spent in the garden was dedicated exclusively to holding a hose. If you’re anything like me, finding ways to water will not only save you a huge amount of time, but it will cut down on your bills and help the planet too.
Perhaps the most direct and sustainable way to reduce water use is to ditch container growing in favor of soil. The large relative surface area to volume ratio of pots means that they will not only dry out much faster than open ground, but will also be subject to wider temperature fluctuations, which can further exacerbate water loss. This is especially the case in containers with porous surfaces, such as fiber-coated hanging baskets or unglazed terracotta, and the smaller the pot, the thirstier your plants will be.
A second way to help conserve vital moisture around the root zone of your plants is to add an insulating layer of mulch. Open a large bag of bark chips, leaf mold or other organic material, spread it in a thick layer on top of the soil between the plants and it will work to not only seal in water but help cool their roots . As it breaks down, it will add further nutrients, food for friendly soil microbes and water-holding spongy fibers, all of which conspire to create the ideal conditions for plant growth.
After all, one of the best ways to reduce your need to water isn’t about keeping it moist, it’s about knowing when and how to water in the first place. First, ditch this little and often approach you hear about so often. Light topical applications will only moisten the surface, which on hot days can evaporate before reaching the plant’s roots. However, giving everything a very good soaking semi-frequently allows the water to penetrate much deeper, where it not only gets where it needs to go, but will create a reservoir for the plants to draw from. Studies have shown that this technique also encourages plants to develop deeper roots, which makes them more resilient even in dry periods.
Finally, although the old idea that watering in the heat of the day can burn plant leaves—because water droplets act like lenses—is of limited value, it’s still not a good idea to water at the height of the day. Most of the water will be lost to the air, and if you water in the cool of the evening, it has extra time to soak in.
Simple changes to what you’re already doing will save you time, money, effort and, of course, the age-old gut-removal battle.
Follow James on Twitter @Botanygeek
