When is the best time to water plants?

When is the best time to water plants?

Best time to water plants

Whether learning by experience or by reading up, you’ll soon come to realise that - for the most part - there are no hard and fast rules for gardening. This applies to irrigation as well. Sure, there are some principles to keep in mind or to apply at different times of the year. But ultimately it’s about adaptability and being flexible. It’s important to let the plants themselves communicate their needs. Much like a dog who wants to go for a walk, they have ways of letting us know when it’s time to irrigate.

The Vegetable Garden
Maybe the first important factor that we should consider when it comes to the best watering time is: where the plants are going to be situated. The garden, the greenhouse, the polytunnel; or indoors on a windowsill? Each of these is a different environment and the plant will have to adapt (as will you) to that environment. Of course, plants outdoors (whether in the garden or in raised beds) will not be relying entirely on you for their watering needs. There may be long periods of drought at times (and this might well be something we’re going to have to live with more and more over the coming decades), but there will also be plenty of days when plants will be naturally irrigated via rainfall. At such times, you can give your watering can a break. Keep an eye on the weather forecast and you can save yourself some work.

Rainwater is regarded as the ideal form of watering by many gardeners. Indeed, if plants could talk themselves they would likely confirm this for us. (Speaking of which, have you ever seen the film The Ruins? Pretty horrifying.) Rainwater is naturally on the slight side of acidic, which is something that plants really thrive on. It contains nitrates and is free of chemicals like chlorine which are added to our water supply. Take a look around at nearby foliage or shrubbery after the next heavy rainfall and see for yourself. Plants will look greener and more vital. The rain also tends to give soil a good healthy soak, draining or diluting sodium buildup.

View Article: The Quickcrop Garden Irrigation System

Outdoor plants shouldn’t be watered every day. Depending on conditions (e.g. not overly dry, drought-like weather), irrigation can be spaced out and done every 2 weeks or so. Which should free you up for other important activities! Andrew, one of the bosses here at Quickcrop is a firm believer in treating outdoor plants ‘mean’ for their own benefit: when you don’t irrigate too often, the roots will work harder to find moisture in the soil, which makes for stronger crops.

The Greenhouse and the Polytunnel
On the other hand, plants in a greenhouse will need much more attention from you. Temperatures can rise pretty high in a greenhouse (and in a polytunnel for that matter). Indeed if real life gets in the way of your gardening duties, things can escalate to the point where plants suffer from heat shock or wilting. Irrigation is by no means your only way of preventing this (ventilation and cooling also play important roles), but it is an important one. So is timing. Moisture can evaporate very fast in this enclosed environment. Greenhouse plants may have to be watered Here you can remove the dilemma of timing entirely by setting up a drip irrigation system, which provides a steady, measured supply of water directly to the soil. Drip irrigation comes highly recommended. It’s something of a gamechanger and can save you untold amounts of time and decision-making. But if you don’t want to go down that route and prefer to potter around and do your watering manually (which is no less valid!), then there are some things to keep in mind when it comes to timing. Many gardeners and food growers live by the principle: water in the morning or evening. Which brings us to our next sub-heading.

View the Baccara automatic water timer

Morning or Evening?
Some common advice you will hear about the best time to water your plants is to do so in the morning or the evening. It stands to reason. Irrigating early in the day when the sun is not at its strongest gives your plants time to absorb moisture. In the evening a similar principle applies, although some gardeners avoid this as it can lead to standing water on the plants. This is particularly a concern if you live in a humid area: moist plants overnight could potentially cause fungal or mildew problems. Your mileage on this may vary though; in reality they’ll often be just fine. Late-evening irrigation also means that the moisture can soak deep into the soil without having to worry about the midday sun drying things out.

View the Galvanised Watering Can

Observe Your Plants, Water When Needed.
With outdoor plants, a quick and simple soil test can tell you whether irrigation is needed, Stick a trowel in the soil to check for dryness. You can use your finger as well by pushing it into the soil until it’s halfway buried. If the soil is moist, watering will not be necessary. If the finger comes out clean and dry, insert it further again. If it’s still dry, it’s time to fetch your watering can. You can also apply this approach to indoor plants in pots or containers.

Speaking of pots and containers: soil in small containers tends to dry out faster than with larger ones. If you grow for long enough you will eventually get a feel for how a pot should weigh when it’s dry, as opposed to when it has healthy levels of moisture. This kind of ‘earned knowledge’ extends to sensible irrigation in general. When you’re a relative beginner it can feel a bit confusing when you see people extol the virtues and importance of irrigation on the one hand, while cautioning against the scourge of overwatering on the other. Which is it?! With experience, a lot of this stuff will become second nature, even if it takes a few fallen soldiers to get there. You will also get a feel for how often individual plants need to be watered: this one is needy, but that one over there is made of steel.

Water Deeply

If watering is to be a relatively infrequent occurrence (such as in the case of outdoor plants), then it’s all the more important to ensure that you’re watering deeply. With 'deep watering' you want the moisture to be seeping around 8 inches deep into the soil. It encourages deep rooting, with plants becoming stronger and more self-reliant. Again, you can measure effectiveness here by using your hand or finger to test the soil. 

View the Spray Watering Lance

There are times when it will become evident that your crops need some watering. At this point it’s a garden emergency, so to quote Moloko: the time is now. However, always double-check soil moisture as signs of underwatering can often be signs of overwatering as well. Overzealous watering arguably kills more plants than underwatering will. Telltale symptoms of parched or stressed plants include:

  • Browning Leaf Tips Browning at the margins or at the tips of leaves is a sign that the plant is drying out. (Be aware that it can also be a sign of overwatering!). Young plants in particular are susceptible to this condition, which can be very visible, almost like your plants have been singed. The science of it is kind of interesting. Moisture travels through the plant from the roots through stems and so on (this is known as transpiration). The leaf tips, in a way, are the last stops on this journey. Therefore if there’s a shortfall or deficit of water the leaf tips will be the first place that it becomes visible. The good news is that these plants can be saved. You will need to remove the damaged areas and with some tender care the plant itself will recover (fingers crossed).
  • Drooping Do you see drooping or lifeless-looking leaves? This can be another sign of plants not getting sufficient water. Again, this can also come about as a result of over-watering (this gardening lark can be confusing). Other possible causes include cold drafts or extreme heat. If you check the watering requirements for the individual plant that’s affected, this can give you a good clue for where you’ve been going wrong. Overwatering can affect the plant by saturating the soil and preventing the roots from absorbing oxygen.
  • Wilting is somewhat similar to drooping, A close cousin, if you will. Compared to drooping, it can be a more reliable indicator of dryness or underwatering. Water enables a plant to stand proud and tall. When the plant lacks moisture, its posture will suffer. This is what causes the distinctive, almost theatrical effect of drooping or wilting. A wilting plant will often display additional symptoms such as drying or browning. Keep in mind that if plants are not taking in enough water because of root damage, irrigating may not help. Therefore it’s a good idea to check for additional symptoms like dry soil. Wilting can sometimes happen after transplanting.
  • Slow Growth Water plays a vital role in photosynthesis. Low rates of photosynthesis can limit growth noticeably. The flip side to this is that if soil is waterlogged, this can also slow down photosynthesis and transpiration, which will make for unhappy plants.