Do you remember the last real heatwave? Weeks without rain, temperatures beyond 35 degrees, and total drama in the garden: drooping leaves at midday, cracked soil, plants that never seem satisfied despite daily watering.
That wasn't bad luck. That was a soil issue.
Because the soil is what decides how long water remains available – not the garden hose. Anyone with soil that stores water and releases it gradually waters less, harvests more, and sleeps better when the next heatwave hits. And it will come. That is no longer a question, but a reality.
In this article, we’ll show you how to make your garden heat- and drought-resistant step by step – using natural solutions that really work.
Why conventional soils fail in the heat
Imagine your garden soil is a sponge. A good sponge absorbs water, holds onto it, and releases it slowly. A bad sponge is either hard as a rock, letting water just bead off, or it’s so loose that everything runs straight through.
Most garden soils, especially sandy or heavily cultivated ones, fall into the second category. Water drains quickly or evaporates from the surface before it can reach the roots. In the heat, this becomes a real problem: the soil dries out in hours, the plant goes into stress, and you’re standing there twice a day with the watering nozzle.
Furthermore, dry soil loses its structure. It hardens, compacts, and the next time you water, it barely soaks in – it just runs off the sides. A vicious cycle.
What you need is soil that stores water like a reservoir and releases it when needed. That is exactly the idea behind targeted soil improvement with zeolite.
What zeolite specifically does in the heat
Zeolite is a volcanic mineral with a unique, highly porous structure. Think of tiny sponges that can absorb and hold water – that is essentially zeolite in the soil.
Scientific studies show that soils with added zeolite hold significantly more water than untreated soils. In practice, this means that after watering or a rain shower, water remains available in the root zone longer instead of immediately draining away or evaporating.
But zeolite can do even more: it binds nutrients like potassium, calcium, and ammonium – the very substances that are quickly washed away during intensive watering. Especially in summer, when you water a lot, this is crucial: the plant doesn’t just get water, it also remains well-nourished.
And another effect many overlook: zeolite improves soil structure. Well-structured soil does not compact as easily, allows water to penetrate better, and does not form a hard crust that causes rain and irrigation water to simply bead off.
Mulching: The underestimated heat protection
Before we get to the specific measures, here is a point that is often underestimated: mulch.
A 5–10 cm layer of mulch on the bed is worth its weight in gold in the summer. It reduces evaporation from the soil surface by up to 70%, keeps the soil cooler, and protects soil life from direct sunlight. Straw, grass clippings, bark mulch, leaves – anything is better than bare soil.
Mulch and zeolite complement each other perfectly: zeolite stores water deep in the soil, while mulch prevents it from evaporating from the top. Together, you can halve your watering needs – without your plants suffering.
Step by step: How to make your garden climate-proof
Step 1: Analyze and understand your soil
Before you buy or incorporate anything, take a look at your soil. Press a finger into it – how far do you get? Is the earth still wet after a rainy day, or is it dry again? Does a puddle form after watering, or does the water soak in quickly?
Sandy soils dry out quickly and need more zeolite for water storage. Loamy soils hold water better but tend to compact – zeolite helps here too by improving structure. Humus-rich soils are already well-positioned, but can still benefit from supplementation.
Step 2: Incorporate BODENKRAFT Zeolith PUR
Our BODENKRAFT Zeolith PUR – activated zeolite in the optimal grain size for garden use – is your most important tool for heat-resistant soil.
For vegetable beds or perennial borders, we recommend 1–2 kg per square meter for new plantings, worked into a depth of 10–15 cm. For existing beds, a maintenance amount of 300–500 g per square meter, hoed into the surface, is sufficient. Once well-incorporated, zeolite remains in the soil permanently – you don't need to repeat the initial treatment every year.
Step 3: Build up organic matter
Zeolite is a storage medium – but it needs something to store. Always combine it with organic material: well-aged compost, horn shavings, or manure. The organic component provides nutrients and further improves soil structure. Zeolite then ensures these nutrients are not immediately washed away.
Rule of thumb: One bucket of compost and a handful of BODENKRAFT PUR per planting spot – that is a good foundation for the summer season.
Step 4: Activate soil life
A living soil is a resilient soil. Soil organisms – bacteria, fungi, worms – improve soil structure, make nutrients available, and help plants grow well even under stress.
This is where our AM PLUS comes in: active microorganisms that specifically build up the soil microbiome. In heat-stricken soil that often dries out, soil life suffers particularly. AM PLUS helps stabilize this balance – and works excellently with zeolite because the porous zeolite structure offers an ideal habitat for the microorganisms.
Step 5: Rethink your watering strategy
This sounds banal, but it makes a huge difference: water in the morning, not at midday or in the evening. In the morning, the water has time to soak into the root zone before the midday heat evaporates it from the surface. Watering in the evening keeps the leaves wet overnight – which encourages fungal diseases.
And: water less often, but thoroughly. Daily shallow watering keeps the roots near the surface – exactly where it is hottest and driest. Infrequent, deep watering forces roots to grow deeper – where it is cooler and moister. Together with zeolite-improved soil that holds water longer, twice a week is often sufficient.
Specifically protect heat-sensitive plants
Some plants are particularly susceptible to drought stress – and deserve extra attention:
Tomatoes and peppers react extremely to fluctuations in water. Blossom end rot, fruit cracking, blossom drop – all symptoms of inconsistent water supply. Here, a particularly well-prepared planting hole with plenty of BODENKRAFT PUR is worth it.
Lettuce and spinach bolt to seed immediately in the heat. This cannot be completely prevented, but cooler, consistently moist soil delays it significantly. Mulch and zeolite help – and, of course, a shady location.
Herbs like basil or parsley do not like extreme temperature fluctuations in the soil. Especially in pots and containers, they are at risk – here, a substrate containing zeolite is almost mandatory.
Berries and fruit trees suffer in the summer mainly from competition: when the soil dries out, they fight with weeds and other plants for the little water available. Well-prepared soil with high water-retention capacity makes the difference here between a good and bad harvest.
What you should NOT do in the heat
A few classics that are well-intentioned but counterproductive:
Do not water in full sun. Most water evaporates immediately before it can soak into the ground. Additionally, water droplets on leaves can act like small magnifying glasses.
Do not water a little bit every day. It is better to water infrequently and thoroughly – this encourages deep root growth.
Do not till the soil when it is bone-dry. This completely destroys the remaining soil structure and makes evaporation even worse.
Do not plant during extreme heat. If you can avoid it, don’t transplant new plants in the heat. Transplant shock plus drought stress is too much for many plants to handle at once.
The big advantage: You do the work once – and benefit for years
The great thing about good soil improvement is that you do it right once, and your garden becomes permanently more resilient. Zeolite remains in the soil, the structure improves over years, and soil life establishes itself.
You will notice a difference in the first year. In the second year, your soil will be noticeably different. And after a few years, you will have a garden that handles a crazy heatwave much better than your neighbors'.
This is not magic. It’s just soil functioning the way it should.
If you want to get started: you can find BODENKRAFT Zeolith PUR and AM PLUS in our shop – and if you are unsure how much you need for your bed, just write to us. We’re happy to help.
Happy harvesting – even when it gets hot again. 🌞
→ You can find everything that can naturally support your garden soil in our garden collection.
About the author
Michaela Schirmbrand-Pfeiffer is an entrepreneur, coach, and co-founder of STEINKRAFT. Her passion: the potential of both humans and the earth. She believes that the earth unfolds itself – if we give it the right space. In her garden blogs, she shares knowledge that enables better decisions: for healthy soil, nutrient-dense food, and a life in harmony with nature.
