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Plant Watering Guide: How often and how much should you water your plants

Wondering how often you should water your plants or how much to give them? At Muddy Trowel, we’re passionate about helping you care for your plants, so read on for a few handy tips and tricks!

First, here are some key things to remember:

  • Large and infrequent watering is better than little and often
  • The larger the pot, the greater the volume of water it can absorb into the soil
  • Covering the compost or soil with a layer of mulch reduces the evaporation of water from the surface, preventing it from drying out
  • You shouldn’t need to water more than every few days during a typical British summer
  • Many plants aren’t big drinkers and will happily be watered less frequently

Contents

  • Why do plants need water
  • Is my plant thirsty
  • How often should plants be watered
  • How much water is too much
  • Does watering have to be hard work
  • Taking a break from watering

Why do plants need water?

Plants need water to keep their stems rigid to transport food from the soil, keep cool in the summer, and photosynthesise. Getting the watering right for your plants will reward you with healthier, stronger plants that flower longer and have better resilience against troublesome insects, slugs and snails.

The trick is to know when to water and how to prevent overwatering. Water is a precious resource and should be used sparingly. Increasingly, gardens are being designed with reduced rainfall and water requirements in mind. When you water, try to be as efficient and effective as possible.

Container gardening: the roots of your plants can’t venture beyond the confines of the pot to find more water, so getting the balance of watering right is important.

Is my plant thirsty?

How can you tell if your plant needs water?

Physical soil check

 person checking soil in plant pot, with their finger to find out if a plant needs watering

When you stick your finger 2 inches or 5 centimetres into the top of the soil surrounding the plant, does the soil feel dry?

If the answer is yes, then you should water your plant thoroughly. You can use tap water, although rainwater is even better from an environmental perspective. Apply the water to the base of the plant, and avoid getting it on the leaves. In summer, overhead watering onto leaves can increase humidity around the plant, leaving it susceptible to powdery mildew and airborne infections.

Seasonal check

Are the days getting longer and temperatures increasing? Is your plant showing active signs of growth or flowering?

The seasons your plants are preparing to bring you joy and when they are delivering their peak performance is when they will need to be watered the most. During winter, most plants can be watered infrequently due to them being dormant and not requiring much water to sustain them in their inactive state.

During spring and particularly summer, it’s important to support your growing plants as much as possible. As temperatures increase and your plants form new growth and flower buds, this is the time when you need to water them frequently to ensure they can absorb the minerals and nutrients they need to continue to put on a fabulous display.

Weather check

Has your plant been exposed to a few days of warm or windy weather?

Weather is becoming increasingly unpredictable. As well as heat and sunshine drying out the soil and increasing a plant’s need for water, the wind has the same effect by wicking moisture away from the plant and the soil. Combined, heat and wind will make your plant very thirsty, and during these weather conditions, your potted plants may need watering daily.

Visual check

Do the leaves look like they are starting to droop or losing their taut structure? Are the tips of the plant beginning to bend over and feel lax and soft?

If the answer is yes, then your plant could need more water. However, confusingly, many plants respond to overwatering with the same visual symptoms, so the next thing you should do is check the physical soil check above.

How often should plants be watered?

Large and infrequent is better than little and often

How much water is enough? You might think that a little daily sprinkle of water will be the most effective way to keep your plant healthy. The problem with this technique, particularly for plants that have a root ball bigger than a shot glass, is that the water will not be enough to penetrate the roots. This means the soil’s surface will be moist and may look watered, but the soil will remain dry underneath.

Depending on how dry the soil is, you could need to add 15 litres of water to a large 50cm diameter container and about 8 litres of water to a 30cm diameter container. You could begin by watering the pot or container until the water starts pouring out of the drainage hole. Ideally, you want to get used to watering your containers enough, so this happens only a small amount, so as not to waste water unnecessarily.

Once you have become a dab hand at watering, you will find that the container compost will remain absorbent and take up and hold water well enough that you shouldn’t need to water more than every few days during a typical British summer.

Rescuing a very parched plant

a plant pot outdoors, in a bucket

There are times you may forget to water and end up facing a poorly plant or rock-solid compost that has lost its ability to retain moisture. It happens to all of us, so don’t give up. Plants are tough, and perennials, in particular, will fight to survive.

Eight steps to revive a plant

Try the following emergency revival procedure, and you’ll have a good chance of rescuing your plants:

  1. Find a bucket or a large trug (a sizeable plastic gardening basket with carrying handles and no holes in the base) that you can place your container inside
  2. Put the bucket or trug in a position that is in the shade, out of direct sunlight and sheltered from drying winds
  3. Fill the bucket or trug with water with your container sat inside, up to just below the lip of the container
  4. Leave to soak for 30 minutes
  5. Lift out your container from its bath and leave it in the shade to drain any excess water
  6. Keep the water you have used for soaking for when you water your plants next
  7. Nurture your container plants by keeping them out of direct sunlight and winds until they have perked up and are looking healthier again
  8. Cut off any dead or yellowing stems and leaves – by reducing the size of the plant, you red

Beware the rain fallacy

If it’s been raining, you shouldn’t need to water your plants, right? Well, unfortunately, this is not always true. It all depends on where your plants are located, how heavy and prolonged the rainfall is and how big a pot they are in.

Potted plants and plants grown in beds next to walls and fences or building windowsills will often not benefit from rainfall due to the structure next to them creating a rain shadow. What this means is that the wall, fence or building is actually deflecting the falling raindrops. You can often see a dry section at the base of walls that rarely receives rain. If your plants are located in the rain shadow, you will need to continue watering them even if you’re experiencing the wettest summer on record!

If your plants aren’t being sheltered and will benefit from rainfall, then it’s likely that a downpour of at least a couple of hours will be required to water your container plants properly. Light drizzle and intermittent rain showers are unlikely to be enough.

Lastly, the shape and diameter size of the container makes a difference, the larger and more open the container the better, because there is a larger surface area to catch the raindrops.

How much water is too much?

Unless they are aquatic or bog plants, most plants don’t particularly enjoy being sat in waterlogged soil. The fine roots that grow out from the main roots of the plant need air as well as water. Too much water will essentially drown your plant.

  • You can tell if your soil is becoming waterlogged by looking out for the following:
  • Water is pooling on the surface of the soil or around the plant
  • Water is slow to drain away
  • The physical check using your finger feels like you are pushing into a sludgy mess rather than soil
  • When you water your garden pots and containers, the water doesn’t drain through the drainage hole in the base
  • Your plant is drooping, dropping leaves or going yellow (although beware, this can also be a sign of not enough water!)

To avoid overwatering or waterlogging the soil, you should consider:

  • Adding horticultural grit (the grit particles are typically 2cm to 4cm in size), perlite or vermiculite to your compost. These will prevent your compost, which contains fine soil particles, from compacting and will make a looser, free-draining soil environment for your plants
  • Raising your pots off the ground with bricks, tiles etc., just as long as you don’t block the drainage hole underneath the pot. This will ensure that excess water in the compost can drain away easily, and the pot won’t be at risk of sitting in a puddle
  • Putting your containers in a more sheltered location, so they aren’t subjected to significant downpours or water running off from roofs, eaves, broken gutters or drainage from balconies above (if you live in an apartment)

Does watering have to be hard work?

Absolutely not. There are loads of things you can do to make life easier for yourself.

Here are some you should consider:

Choose plants that like it on the dry side

Many plants aren’t big drinkers and will happily be watered less frequently, even during the height of Summer. Mediterranean herbs are a very good example – you can find herb gardens in the Muddy Trowel shop containing rosemary, thyme, sage and more.

The bigger, the better

The larger the pot, the greater the volume of water it can absorb into the soil and the less often you need to water it, albeit, when you do, give it a really good drenching! If you aren’t using one of the Muddy Trowel pots for your plants, always make sure there is a drainage hole in the base of your container, so excess water can drain away, preventing your plants from becoming waterlogged.

Watch out: for blocked drainage holes that can get filled with compost. To avoid this, place a few tiles or pieces of broken ceramic or terracotta pots at an angle over the drainage hole to stop the compost from falling down the hole and blocking it up.

Dress up your pots

Topdressing or mulching describes the process of covering the surface of the soil with either organic matter, such as well-rotted manure, compost, wood clippings, coconut coir or moss, or other materials such as gravel, pebbles, grit or even broken terracotta tiles.

Covering the compost or soil with a layer of mulch reduces the evaporation of water from the surface, preventing it from drying out. It helps the soil remain absorbent and has the added bonus of suppressing weed growth. It can also look beautifully decorative, depending on what you use.

Make your pots social

Placing your containers together in a friendly group can not only look fantastically abundant and colourful, but it’s also a beneficial thing to do for your plants. It helps the plants create a little micro-climate where they control the temperature and to some extent, the humidity around them. It also helps protect more tender plants from cooler nights and makes watering easier for you, because they are located in the same place, and you don’t have to lug a heavy watering can too far.

Watch out: when the weather is very hot and humid, your plants might be at risk of developing powdery mildew due to reduced airflow between the plants. Try to space the pots so they are not too crowded against each other and so that plants aren’t leaning on each other or foliage overlapping between plants.

Saucers for pots

In months when it’s sweltering and dry, it can be highly effective to place a saucer under your pot that you can add water to in the morning, and the moisture will be pulled up from the base of the pot towards the roots of the plant. It will also encourage your plants to develop deeper roots to reach the water.

Watch out: leaving your container to sit in water in the saucer for prolonged periods. Allow the saucer to run dry completely and use the physical check finger test to understand whether you should add more water.

Become a sunrise or sunset waterer

Only mad dogs and Englishmen water in the midday sun. The best time to water your plants is before midday and ideally early morning as the sun is rising. Your plants will be waking up to a new day (and hopefully good weather during Summer), so by watering at the start of the day, you are setting them up perfectly.

However, if you aren’t a morning person, it’s fine to do watering in the evening throughout Summer, and it can be a great way to unwind and decompress after work, whilst you enjoy the sunset.

Watch out: watering in the evening as temperatures start to drop and evenings become colder in Autumn, can leave your plants feeling cold and damp overnight and could make them more susceptible to infections and diseases.

Add a little extra oomph to your compost

If your plants are in a space which is a real sun trap, you may want to consider adding moisture retaining granules to your compost. These look like little gritty particles (often dyed blue), that you mix in with your compost. When you water, the particles expand by absorbing the water and look more like small frog spawn. They retain this moisture whilst still making it accessible to your plant’s roots.

Taking a break from watering

An alternative watering solution is required for those with little free time or when you are going away for a few days.

The key pieces of advice we can give you when you are considering watering solutions or irrigation systems is that you should:

  • Be prepared for trial and error
  • Consider using a mixture of watering solutions for your plants and even for the same container
  • Leave sufficient time before you go on holiday or leave your plants, to monitor the watering solutions for their effectiveness and make improvements

Watering solutions

There is so much to choose from, but here are two of the most common solutions that exist:

Drip irrigation:

These are a series of tubes that connect either to a bag or a container filled with water that is higher than the soil you are watering (and therefore gravity fed). The tubes are either permeable and rest on the surface of your soil or are plastic and have dripping ends positioned above the soil that you can adjust to alter the flow rate of the drips. There are alternative drip solutions that have a single spike you can screw onto a 2-litre drinks bottle that can be filled with water and then stuck upside down into the soil. All of these solutions require patience and monitoring to check the correct amount of water is being fed to your container, but if you get this right, you have pretty much effortless watering for the season, with the exception of refilling gravity fed containers from time to time.

Capillary matting:

Matting that you line a large saucer or trough with and then place your containers on. The matting acts as a giant sponge and will soak up water that you pour onto it and reduce your pots from drying out at the base. You still need to periodically water your pots to keep them healthy, so it’s rarely a setup and forget solution. However, it’s ideal in the event you wish to go away for a long weekend.

Going on holiday and need peace of mind? There really is no substitute for a friend, family member or neighbour popping by every couple of days to water your plants. Perhaps in return, you can treat them to a bundle of joy from Muddy Trowel!

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