“How often should I water my Geraniums?”

It's one of those questions that sounds as though it should have a really simple answer.

Every day? Twice a week? Once a week?

Unfortunately, we're going to give you the slightly annoying gardener's answer...

It depends!

The plants most of us call Geraniums in pots, hanging baskets and window boxes are actually Pelargoniums, and while they need regular watering during active growth, they really don't appreciate sitting in constantly wet compost.

Here at Growing Crazy we grow hundreds of different Pelargoniums, from young plants in small pots through to large specimens and plants within our Plant Heritage National Collections®.

If there's one thing we've learnt from watering that many plants, it's this:

Don't water according to the calendar. Water according to what the plant and compost are telling you.

How often do Pelargoniums in pots need watering?

During warm summer weather, a large Pelargonium growing in a relatively small pot may need watering every day.  During cooler or cloudy weather, that same plant might go several days without needing water.

In spring and autumn, watering frequency usually reduces considerably and during winter, a Pelargonium being kept cool and frost free may need surprisingly little water at all.

That's why we'd be very wary of advice telling you simply to “water your Geraniums twice a week”. Sometimes that might be exactly right sometimes it could leave your plant desperately dry.  And sometimes it could slowly drown it!

The finger test

For home growers, one of the most useful pieces of watering equipment is something you already have...

Your finger!

• Push your finger slightly into the compost and feel whether it is still damp beneath the surface.
• If the compost still feels noticeably moist, the plant probably doesn't need watering yet.
• If it feels dry and the pot is becoming noticeably lighter, it's probably time to water.

You'll quickly get used to recognising the difference.

Learn the weight of your pots

This is something you get very used to when you're handling lots of plants.

Pick up the pot!

A pot containing wet compost is considerably heavier than the same pot once the compost has dried. With a bit of practice, you can often tell whether a plant needs watering simply by lifting it. It's particularly useful with smaller pots where the difference in weight is really noticeable.

Between looking at the plant, feeling the compost and lifting the pot, you'll usually get a much better answer than any fixed watering schedule could give you.

How should you water a Pelargonium?

When a Pelargonium needs watering, give it a proper drink.

We're not trying to keep the very top of the compost permanently damp by adding tiny amounts of water every few hours. Water the compost thoroughly so moisture reaches the root system, allow excess water to drain away and then wait until the plant needs watering again.

Good drainage is incredibly important. Pelargoniums generally cope much better with occasionally becoming a little dry than they do with having their roots sitting permanently in cold, saturated compost.

Don't leave pots standing in water

If your Pelargoniums are standing in saucers, decorative pots or trays, make sure excess water isn't permanently collecting around the bottom of the pot.

After watering, allow the plant to drain. Continually saturated compost reduces the amount of oxygen available around the roots and creates ideal conditions for root problems and rotting.

What happens if I overwater my Geranium?

Overwatering is probably one of the most common problems we see with Pelargoniums grown in pots.

Signs can include:

• Yellowing leaves

• Leaves dropping from the plant

• Soft or unhealthy growth

• Compost remaining wet for long periods

• Poor growth

• Root problems

• Stem or root rot in more serious cases

The confusing part is that an overwatered plant can sometimes look wilted. That can persuade you to give it even more water!

If a Pelargonium is wilting despite the compost being wet, don't automatically reach for the watering can.  Check what's happening around the roots.

What happens if a Pelargonium gets too dry?

Pelargoniums are quite tolerant of short periods of dryness, but they're not cacti!

A plant that becomes excessively dry may wilt dramatically, and the leaves can become limp. Flowers may fade more quickly and developing buds can be affected.

If this happens, give the plant a thorough watering and allow it time to recover - but don't drown it or leave it standing in water!  Water it, allow it to drain and come back to it later on.

Repeatedly allowing a plant to reach the point of severe wilting isn't ideal, particularly when you're trying to encourage lots of growth and flowers. We're aiming for the middle ground:

Not permanently wet and not permanently bone dry.

Watering Pelargoniums during hot weather

This is when things can change very quickly.

A large, leafy Pelargonium covered in flowers can use a surprising amount of water on a hot, sunny day. Plants growing in greenhouses and conservatories can dry particularly quickly because temperatures can become much higher than they are outside.

Hanging baskets and small containers also have a relatively small volume of compost compared with the amount of foliage they're supporting.

During really hot weather, check your plants every day. BUT that doesn't mean they automatically need watering every day - it means you should check them every day and water those that need it.

There's an important difference!

Morning or evening - when is the best time to water?

If possible, we like to get watering done in the evening.

That gives the plants access to water over night and before the daytime temperatures rise and allows any water accidentally splashed around the foliage or growing area time to dry.

 

Does the type of pot make a difference?

Absolutely the type of pot they are in can have a big impact on how quickly a plant may dry out or indeed retain the water!

Terracotta pots

Traditional unglazed terracotta is porous, so moisture can evaporate through the sides of the pot. That means Pelargoniums in terracotta can dry more quickly, particularly during hot weather.

Plastic pots

Plastic doesn't lose moisture through its sides in the same way, so the compost may remain damp for longer. 

Small pots

Small pots contain less compost and therefore have a smaller reservoir of moisture. They can dry surprisingly quickly.

Large pots

Larger containers usually dry more slowly, although a huge established plant can also use an enormous amount of water. This is another reason why a single watering schedule doesn't work.

BUT - make sure whatever pot you are using has drainage holes for the water to run off so the plant is not sat in water for too long.

Compost makes a difference too

Not all compost holds water in the same way. Some mixes are very free draining, while others retain moisture for considerably longer.

The structure of older compost can also change over time. This is why we keep coming back to the same principle:

Check the plant and check the compost.

Don't assume a plant needs water simply because another Pelargonium next to it needed watering.

What about plants in tiny pots?

Young Pelargoniums in small pots need particularly careful attention. Because there's only a small volume of compost, they can dry very quickly.

But there's another danger.

A tiny plant with a small root system isn't using the same amount of water as a huge mature Pelargonium. Keeping that small volume of compost permanently saturated can be equally damaging. (This is where people receiving new young plants can make a "killing with kindness" error!!)

This is one reason we're not huge fans of putting a very small Pelargonium straight into an enormous pot. The large volume of compost around a small root system can stay wet for far too long. Pot up gradually as the plant grows.

Should I water from the top or the bottom?

Both methods can work.

We always water from the top of the pot and for most home growers, watering the compost thoroughly from above is perfectly fine.

Try to direct the water towards the compost in the top of the pot rather than soaking the leaves and flowers.

Bottom watering can also be useful, particularly for smaller plants, but don't leave pots sitting in water indefinitely.

Allow the compost to absorb the moisture it needs and then let the excess drain away.

Should you water Pelargoniums in winter?

Yes — but much less frequently.

This is where summer watering habits can get people into trouble. As temperatures fall and light levels reduce, Pelargoniums grow much more slowly. 

A plant that needed watering every day during July might need very little during the coldest part of winter. If you're overwintering Pelargoniums somewhere cool and frost free, keep them on the drier side.

Cold, saturated compost is exactly what we don't want. 

Check plants regularly, but don't water them automatically simply because it's “watering day”.

What about very hot Pelargoniums in a greenhouse?

Growing under glass brings its own challenges.

A greenhouse can become extremely hot on a sunny day and plants can lose water rapidly.

Ventilation, shading and air movement can all help reduce stress, but you'll still need to monitor pots carefully.

Here at Growing Crazy, with hundreds of different Pelargoniums growing together, we can't simply assume every plant needs exactly the same amount of water.

Some are huge and growing vigorously, some are young plants, some are species with very different natural growth habits and some are having a bit of a sulk!

Good watering is about observation.

Our Growing Crazy watering checklist

If you're wondering whether your potted Pelargonium needs watering, ask yourself:

• Does the compost feel dry?

• Does the pot feel lighter than usual?

• Is the plant actively growing?

• Is it hot and sunny?

• Is it in a small pot or hanging basket?

• Is it growing in terracotta or plastic?

• Is it outside or under glass?

• Has the weather suddenly become cooler?

• Is the compost still wet from the last watering?

• What time of year is it?

And then make the decision.

Not because it's Tuesday and Tuesday is watering day! :-)

So, how often should I water my Geraniums?

If you've arrived here looking for a simple number, we're sorry!

There genuinely isn't one.

During a hot spell in summer, you might be checking and watering some potted Pelargoniums every day.

During cooler weather, they may need watering only every few days.

During winter, plants kept cool and frost free can go considerably longer.

The best advice we can give you is:

Check your Pelargoniums regularly, water thoroughly when they need it and then allow the compost to begin drying before watering again.

Once you stop watering according to a timetable and start looking at the plant, the pot, the compost and the weather, watering Pelargoniums becomes much easier.

And you'll probably find yourself automatically picking up pots to check their weight before too long.

That's when you know you've caught the Pelargonium bug!

Happy growing! 🌿