Watering is a key, necessary aspect to ensure a flourishing garden: plants are comprised of approximately 80% water, and its only means of drawing up nutrients from the soil, which it does by absorbing nutrients in a water-based solution through its roots. A few rules need to be followed to ensure proper watering. Just like too little water, too much can have a negative effect on plant growth.
The frequency of watering depends on several different factors. A frequent error made by gardeners is watering too frequently. In this case, the plant isn't encouraged to develop its own root system to go and search for water at a deep level, and it becomes dependent on the surface water provided.
Several factors need to be taken into account:
Your soil texture
Depending on the texture of the soil, and whether it is compacted or not, it will have a greater or lesser ability to hold water and this water seeps down to the roots.
- If it is sandy, water often and a little at a time (because this type of soil cannot hold a lot of water).
- If it is clay-like, you can freely water with large quantities of water, but water less often.
The ideal is to have a silty-clay soil, with a lumpy texture, similar to coffee grounds. To get this, you need to regularly add in some compost, and turn it over at the surface with a garden fork from time to time: “Turning over is equivalent to two watering sessions” but is a lot simpler and requires much less effort: Mulching means zero watering for the whole year!
The weather and rainfall
Install a rain gauge in a cleared area of your garden. A rain gauge is a tool requiring very little investment, yet it’s really useful.
1mm of rain represents 1 litre of water per m², so you will often be surprised when taking water readings from your gauge: heavy rainfall lasting a few minutes often brings less water than a fine drizzle that lasts for several hours.
The other use for rain gauges: finding out whether it’s necessary to redo some application or not. If you measure 20mm of rain in the few days following the application of a contact product such as a Bordeaux mixture, you would need to redo the application, as it will have all leached out.
What's more, favour rainwater over tap water. It is not as cold, not chlorinated, and is more cost-effective! To do this, you could use a rainwater collection tank at home.
The positioning of plants in your garden
Plants will need different quantities of water, depending on where they are placed in the garden. Are your plants north-facing, south-facing, exposed to wind, or sheltered?
Depending on specific plant requirements
Some species do well in damp environments, others thrive in times of drought!
For example, vegetables such as garlic, onion, shallot, asparagus and artichoke require little watering whereas gourds, lettuce varieties, tomatoes and cabbages require a lot.
How to water
Favour watering with the good old watering can, drip systems located at the base of plants or, for large areas, a sunken irrigation system. Sprinkling or spraying consumes more water and encourages the onset of diseases, especially on tomatoes, potatoes and beans.
Remember to water regularly during the hot months. From Spring to Autumn, water early in the morning, but in Summer, wait until the evening. And never water in full sun, to avoid burning your plants.
When watering exposed soil, approximately 50% of it returns to the surrounding atmosphere! Mulching restricts water evaporation and therefore cuts down on watering needs.
When the soil is exposed (a situation that doesn’t occur in nature), water loss through evaporation is very high (three times higher in fact, than in forest soils). To these losses we need to add those due to the transpiration of plants whose roots heat up severely in summer. Mulching prevents this water loss.
During a heavy rain storm, the mulch acts like a sponge and prevents water from gushing down into the soil without seeping into it, and it keeps the soil cool and loose in summer.
Mulching your garden allows you to go on holiday in spring and summer whatever the weather conditions: if it rained while you were away, weeds will not have invaded your kitchen garden and flower beds. On the other hand, in times of drought, plants would not have suffered because the evapotranspiration will have been considerably limited.