Pot watering 101: how to water your outdoor pots and containers through summer
Pots and containers need more of a helping hand than their ground-grown counterparts. Their roots are contained, unable to source water from deep within the soil – and there are many variables that can affect how frequently they need watering.
To understand their needs better, the questions below break down the different factors that determine how to best water your outdoor potted plants this summer. 
How often should you water outdoor pots?
There is no one correct answer, and a rigid watering schedule will likely let you down through the hottest months. Your ideal watering frequency is determined by pot size, potting mix, container material, plant size, the plants needs, where the pot is positioned, and of course - the weather. Once you can identify these factors, you can tailor an approach that’s right for you.
That being said, it’s almost certain that throughout summer, the frequency at which you water your pots should increase.
If you are ever in doubt, it's helpful to check below the surface before you water, by inserting a finger a few centimetres into the potting mix. If it's obviously moist beneath, watering can probably wait, but if it’s dry below the surface, it’s time to reach for the watering can.
How does the material of a pot affect how quickly it dries out?
You’d be surprised how much the material of your pots and containers influences how much watering you’ll need to do.
Terracotta, a garden classic, is porous. This means moisture is lost through the wall of the pot, as well as through the drainage holes, so it dries out more quickly. In warm or windy conditions, they’ll need monitoring frequently.
Plastic, on the other hand, is not porous. It retains moisture within the pot, which might mean less frequent watering is needed. The trade-off is that plastic (especially black) can absorb and transfer heat from the sun more readily, raising the temperature and drying out the potting mix drastically when positioned somewhere sunny.
Metal containers also retain moisture but conduct heat, so the same applies to them. It’s also crucial to add drainage holes to any repurposed metal planters, like dolly tubs, to ensure excess water can drain away.
Timber planters typically insulate the potting mix from both heat and cold, which moderates their drying rate better than the alternatives.
None of these materials are necessarily better or worse for container gardening. They simply behave differently, and knowing which you are working with helps you gauge how often they need checking on.
Does the type and quality of compost/potting mix make a difference to how quickly potted plants dry out?
Yes, the type and quality of a potting mix is often underestimated as a factor. Many cheap and readily available multipurpose composts will lead to increased watering, especially as summer goes on and the plants quickly use up nutrients in the soil, changing its structure and ability to retain moisture.
Lower-quality potting mix or compost that don’t contain enough rich organic matter, may drain too quickly, hold moisture unevenly, or develop dry pockets that are difficult to re-wet.
Peat-free potting mix in particular can appear dry on the surface while retaining adequate moisture further down, which is one reason visual assessment alone is unreliable.
If you grow the same plants in containers for more than a year or two, a quality potting mix is worth investing in. Mulching and adding fresh material to your pots can also help replenish the soil over time, ensuring it doesn’t become overly compacted or poor.
Do pots and containers in full sun need watering more?
Direct sun increases soil temperature and accelerates moisture evaporation from the potting mix, while also increasing plant thirst. Both effects mean pots in full sun dry out faster than those in shade or partial shade.
Wind has a similar effect. Exposed positions lose moisture through evapotranspiration from both the soil surface and the plant’s foliage. Pots in a sheltered courtyard will hold moisture longer than pots next to an exposed, south-facing doorway.
It is also worth noting that pots positioned under canopies, eaves, or against walls may sit in rain shadow and receive little or no natural rainfall. It’s not safe to assume a pot has been watered by recent rain if it is in one of these positions. Walls and hard surfaces also absorb heat during the day and radiate it after direct sun has passed, keeping nearby pots warmer for longer.
How much water do pots and containers need?
The aim when watering your pots is to saturate the full volume of potting mix evenly. What matters is that the water reaches all parts of the potting mix, not just the surface, so a slow, even soak is best.
How much water you need to achieve this is dependent on the size of the containers, the potting mix, the position of the pot and of course, the needs of the plant you are watering.
Which watering cans and accessories suit watering pots and containers?
When watering pots and containers, there is no singular can that is better than another. It really is dependent on your needs. You may find a long-reach watering can ideal for reaching into baskets and containers without bending, or you may need a shorter, traditional spout to easily manoeuvre between pots.
A large capacity can is helpful if you have established plants in pots, or you may just need a more compact, lightweight can for smaller pots and baskets. Browse our outdoor watering cans and accessories to find the right fit for your garden.