Watering balcony plants properly: sustainable watering made easy

Sustainable watering on your balcony: how to care for your plants in harmony with nature

March 24, 2026 Gunilla Lehmann
The Grow-your-own-food

Two green watering cans and a rake hanging on a house wall

In spring, everything begins so easily. The soil is moist, the sun still gentle, and your plants grow almost by themselves.

But by summer at the latest, everything changes: the heat increases, the pots dry out faster, and suddenly watering becomes a daily chore.

This is exactly where sustainable gardening begins. With the right methods, you can not only save water, but also make your plants healthier and more independent.

Sustainable watering means: less effort, less consumption, and a closer connection to your plants.

1. Why sustainable watering matters so much
2. Watering in harmony with the plant
3. Using water storage in the pot
4. Mulching in pots
5. Collecting rainwater in the city
6. DIY watering
7. Automatic watering systems
8. Costs & materials
9. Water tank & weight
10. Watering by plant type
11. Conclusion

1. Why sustainable watering matters so much

On a balcony, plants depend entirely on you. Unlike in the garden, their roots cannot reach deeper layers of water, so they live solely on what you give them.

Especially in hot summers, extremes quickly develop: the compost dries out, plants become stressed, and you have to reach for the watering can more and more often.

Sustainable watering helps you balance exactly that. It provides even moisture, saves water and creates stable conditions, even in the heat.

2. Watering in harmony with the plant

The most important foundation is not technology, but observation.

It is best to water in the morning
Water thoroughly rather than often
Let the surface dry out slightly in between

A simple trick: push your finger a few centimetres into the compost. If it still feels moist there, you can wait.

This is how you develop a feel for your plants, and that is exactly the most sustainable form of gardening.

3. Using water storage in the pot

A healthy balcony begins in the pot. The right compost can store water and release it slowly again.

Use compost-rich potting compost
Mix in expanded clay or perlite
choose structurally stable composts
work unwashed sheep's wool into the compost

The better your compost performs, the less you have to water, and the more stably your plants grow.

Planter mulched with sheep’s wool around young plants, a ripe cherry tomato in front

4. Mulching in pots: underrated and incredibly effective

Mulching works in pots too, and it is one of the simplest tricks for sustainable watering.

A layer of straw, leaves or plant debris 3 to 5 cm thick can noticeably reduce evaporation.

Mulch:

keeps moisture in the soil
protects from heat
encourages a thriving soil environment

Especially on sunny balconies, this is a real game changer. Untreated sheep's wool can also be used very well as a mulch layer and water store.

5. Collecting rainwater in the city

You can use rainwater on a balcony too.

Set up buckets or small barrels
Catch the rain deliberately
distribute it with a watering can

Rainwater is soft, low in lime and ideal for plants. At the same time, you noticeably reduce your drinking water consumption.

6. DIY watering: simple & effective

You don't always need a ready-made system. You can easily build many watering solutions yourself, with materials you often already have at home.

These DIY methods are ideal for small balconies, single plants, or when you are away for a few days.

Illustration: upturned plastic bottle with holes in the cap slowly releasing water into the pot

PET bottles as water dispensers

One of the simplest solutions: you take an empty plastic bottle, poke small holes in the lid and push it upside down into the compost.

Water is released slowly to the roots
depending on the size of the holes, the supply lasts several days
ideal for larger pots (e.g. tomatoes)

Tip: Test the hole size beforehand, as holes that are too large let the water run out too quickly.

Illustration: clay watering spike in a flowerpot, connected to a water bottle, keeps the soil evenly moist

Clay cones (watering spikes)

Clay cones work like a natural water dispenser. They are pushed into the compost and connected to a water source (e.g. a bottle).

the clay releases water slowly and evenly
adapts to the moisture needs of the compost
particularly good for herbs and an even supply

This solution is somewhat more reliable than plain DIY bottles and very easy to use.

Illustration: a wick draws water from a glass into the soil of a flowerpot

Wick or capillary system

Here you use a piece of fabric or a string as a “water conductor”: one end sits in a water container, the other is pushed into the compost.

Water is drawn continuously into the pot
works entirely without technology or electricity
ideal for small pots and window boxes

Important: The water container should stand slightly higher than the pot, as the water flows better that way.

Conclusion: With simple means, you can supply your plants reliably. Often a small DIY solution is enough to make watering your balcony much more relaxed.

7. Automatic watering systems

If you want to water your balcony efficiently in the long term, an automatic system is worthwhile. Such systems save time, reduce water consumption and supply your plants more evenly, but depending on the type they also have their limits.

System	How it works	Advantages	Disadvantages	Suitable for
Drip irrigation (e.g. Blumat)	Water is delivered directly to the roots via clay cones or hoses, often controlled by soil moisture	very water-saving (up to 70%) supply matched to need hardly any daily effort	initial installation is somewhat involved regular checks needed (blockages possible) a small height difference is needed for pressure	Herbs, vegetables, larger balconies
Solar watering systems	A small pump distributes water automatically from a tank, powered by solar energy	no power connection needed ideal for many plants at once timer function possible	dependent on sunlight higher purchase costs technology more prone to faults than simple systems	Medium to large balconies
Capillary systems (wick / mat)	Water is drawn from a reservoir into the pots via fabric or mats	very simple and needs no electricity even supply inexpensive to set up	less precisely controllable does not work equally well with all composts limited reach	Herbs, small pots, indoors & balcony
Water tank with drippers	A tank placed higher up supplies plants via hoses using natural water pressure	simple system without electricity combines well with rainwater relatively low maintenance	mind the weight of the tank pressure depends on height even distribution requires fine adjustment	All balconies with several plants

Tip: The most effective combination is often: mulch + drip irrigation + rainwater. This reduces evaporation, saves water and creates stable conditions for your plants.

8. Costs & materials: what do you really need?

Watering doesn't have to be expensive. There are solutions for every budget:

DIY: €0 to €10
Simple systems: €15 to €50
Automatic systems: €50 to €150

You can start small and expand your system step by step.

9. Water tank on the balcony: mind the weight!

A central water tank is practical, but heavy.

10 litres = 10 kg
20 litres = 20 kg
50 litres = 50 kg

So the following applies:

Distribute the weight evenly
Place the tank close to the wall
use several small tanks instead

A 20 to 30 litre tank is often entirely sufficient.

Graphic: water tank on a balcony with a warning sign and 100 kg weight as a reminder of load capacity

10. Watering by plant type

Not every plant has the same needs. While tomatoes need a lot of water, Mediterranean herbs get by with much less. If you adapt your watering to the plant types, you save water and get healthier plants.

Plant type	Water requirement	Recommended system	Special features
Herbs (Mediterranean, e.g. rosemary, thyme)	low	Clay cones, economical drip irrigation	better too dry than too wet avoid waterlogging at all costs well-drained compost is important
Herbs (soft, e.g. basil, parsley)	medium	small drip systems or wick watering	even moisture is important sensitive to drying out regular harvesting encourages growth
Lettuces & leafy greens	medium to high	Drip irrigation or capillary systems	need evenly moist compost dry = quickly bitter ideal for window boxes
Tomatoes & fruiting vegetables	high	Drip irrigation + mulch	very thirsty, especially in summer an even water supply is crucial irregular watering leads to problems (e.g. blossom end rot)
Cucumbers & courgettes	very high	automatic drip irrigation	extremely high water requirement large leaves = strong evaporation large pots necessary
Flowering plants (e.g. petunias, pelargoniums)	medium to high	Drip irrigation or regular manual watering	only flower with an even water supply dry out quickly in window boxes regular feeding is important
Wildflowers & pollinator plants	low to medium	occasional watering or simple systems	often drought-tolerant too much water does more harm ideal for naturalistic balconies
Climbing plants	medium to high	Solar drip systems or drip irrigation	lots of foliage → high water consumption exposed to wind → dries out faster an even supply is important

Tip: If you combine different plant types, group them by water requirement. This lets you control your watering more precisely and save water at the same time.