Heat Today will be hot in the south of the Netherlands: up to 32 degrees! Check whether your reservoir is still full, whether the mix is still moist, shade vulnerable plants around midday, and wait with sowing until it cools down.
All about MM water reservoirs
Since 2025, we've had a unique Makkelijke Moestuin water reservoir beneath the growing mix in your raised bed. It gives your plants' roots air and means you almost never need to water by hand.
It works so well that we recommend it to everyone who wants genuinely easy vegetable gardening.
Can you still garden the MM way without a reservoir and water by hand? Yes, you can, with good results, just as we did from 2008 to 2025.
But: on this page, I'll explain why a smart water reservoir helps your plants grow much better while saving you time and effort: how it works, how to water, and how often that's needed.
It works so well that we recommend it to everyone who wants genuinely easy vegetable gardening.
Can you still garden the MM way without a reservoir and water by hand? Yes, you can, with good results, just as we did from 2008 to 2025.
But: on this page, I'll explain why a smart water reservoir helps your plants grow much better while saving you time and effort: how it works, how to water, and how often that's needed.
Everyone knows plants need water: without it, they die. But they only grow really well when the mix they're in stays consistently moist and airy.
And that's exactly what our water reservoirs achieve.
And that's exactly what our water reservoirs achieve.
Why choose our water reservoirs?
With an MM water reservoir beneath your raised bed, you not only water far less often, but can also check very easily whether you've added enough. That keeps the mix at the right moisture level, so you never need to wonder whether you're doing it correctly.
As a result, your seeds germinate more easily, your plants grow better and faster, and you can harvest both earlier and more.
Look at this endive. We sowed both plants on the same day in mid-July last year: the one on the left grew without a reservoir and was watered every day; the one on the right grew with a reservoir that we filled at the start and then left alone:
Look at this endive. We sowed both plants on the same day in mid-July last year: the one on the left grew without a reservoir and was watered every day; the one on the right grew with a reservoir that we filled at the start and then left alone:
Our new endive variety performed even better. The head itself is already impressive, but take a close look at the root ball. It's beautifully compact and packed with small white roots: exactly how we like to see it.
As well as convenience, they give you much more freedom
Going on holiday for a few weeks in the middle of summer? That's no problem at all.
Fill the reservoirs just before you leave, and your plants will keep growing.
Fill the reservoirs just before you leave, and your plants will keep growing.
Just look at Pyt. This brand-new MM gardener went on holiday for two weeks and was 'very pleasantly surprised' when he came home. Thanks to the reservoirs, his newly sown plants had continued growing beautifully:
In fact, the plants grow so well that they soon spill out of your raised bed. From now on, you won't ask your neighbours to water while you're away, but to come and harvest 😄
What is an MM water reservoir, and how does it work?
MM water reservoirs are smart reservoirs that give your plants' roots exactly what they need: enough moisture, but also air. This helps your plants grow healthy and strong.
We make these hollow reservoirs ourselves from sturdy LLDPE plastic. They can withstand both heat and frost, are 100% food-safe, easy to recycle, and extremely strong.
The watertight reservoirs measure 60 x 60 cm, are 8 cm high, and hold about 15 litres of water.
Here's how they're constructed:
We make these hollow reservoirs ourselves from sturdy LLDPE plastic. They can withstand both heat and frost, are 100% food-safe, easy to recycle, and extremely strong.
The watertight reservoirs measure 60 x 60 cm, are 8 cm high, and hold about 15 litres of water.
Here's how they're constructed:
- at the bottom: a large water reservoir of about 15 litres
- above it: an air layer of about 2 cm
- inside: wicks that draw the water upwards
- on top: the growing mix
That air layer is extremely important. If the mix sat directly on the water, it would become too wet. The gap keeps the mix both airy and moist.
The wicks absorb water from the reservoir and draw it up into the mix, which carries it further, but only as much as needed. This means the mix is never too wet or too dry.
There are also large holes on top for the filling pipe, smaller holes for ventilation and the wicks, and two overflow holes at the sides.
Why is air around the roots so important for plants?
Plants don't only breathe above ground, but below it too, through their roots. The roots use oxygen to convert nutrients such as glucose into usable energy. This process is called cellular respiration, and plants can't grow without it.
In waterlogged soil, the air between the fibres disappears, and so does the oxygen. At the same time, COâ‚‚ that would normally escape becomes trapped.
The result:
- the roots don't get oxygen
- waste products build up
- the roots become damaged and start to rot
- fungi and diseases get their chance
In short: no air in the soil means no healthy roots, and therefore no healthy plant.
Give them that air and everything grows quickly, you can harvest regularly, and you can sow something new in the squares more often:
Give them that air and everything grows quickly, you can harvest regularly, and you can sow something new in the squares more often:
A light, airy mix for water reservoirs
Our Makkelijke Moestuinmix was developed specially for our system, giving your vegetables exactly what they need to grow healthy and strong: moisture, nutrients, water and air.
With a raised bed that has water reservoirs, it's especially important for the mix to remain airy, even during heavy rain. That's why we recommend using our new MM-kokosmix.
How do you water with an MM water reservoir?
Fill the reservoirs through the filling pipes until water begins to flow from the overflow holes at the sides.
1. After sowing
Sun and wind dry out the top layer of the mix fairly quickly. After sowing, continue giving a little extra water from above every day until the seedlings develop their first true leaves. Their roots will then be long enough to reach the moist mix.
Sun and wind dry out the top layer of the mix fairly quickly. After sowing, continue giving a little extra water from above every day until the seedlings develop their first true leaves. Their roots will then be long enough to reach the moist mix.
2. Keep the reservoir filled
Look down the filling pipe to check whether there's still water in the reservoir. Do this:
Look down the filling pipe to check whether there's still water in the reservoir. Do this:
- in dry weather: usually once every two weeks
- during prolonged rain: sometimes it won't be necessary for quite a while, because rain also fills the reservoirs
If you can't see any water, it's time to top it up.
Extra check with traditional MM-mix
During prolonged periods of drought, sunshine, heat or strong wind, traditional MM-mix can still dry out from the top. In summer, check every two weeks whether the mix is still moist further down, using a small trowel or simply your fingers.
If the mix is still dry 8 to 10 cm below the surface, wet it thoroughly from above.
Do this in stages - for example, three times with about five minutes between each watering - so the mix can absorb the water properly. Then check it again.
If you use MM-kokosmix, you don't need this extra check. The coconut fibres continue drawing up water even during prolonged hot, dry weather.
If the mix is still dry 8 to 10 cm below the surface, wet it thoroughly from above.
Do this in stages - for example, three times with about five minutes between each watering - so the mix can absorb the water properly. Then check it again.
If you use MM-kokosmix, you don't need this extra check. The coconut fibres continue drawing up water even during prolonged hot, dry weather.
What if it keeps raining?
Then you don't need to water at all 🙂 You also don't need to worry about the mix becoming too wet. Excess water seeps down into the reservoir and drains away through the side holes, while the mix stays in good condition.
What should you do during a heatwave, with extreme heat and dry wind?
That's a real challenge for young plants and plants with soft leaves, such as lettuce: they can wilt quite quickly. This isn't primarily caused by the mix, but by the hot, dry air and intense sunlight.
Give vulnerable plants some shade and moisten the top layer of the mix. Take extra care to water the mix rather than the leaves.
Give vulnerable plants some shade and moisten the top layer of the mix. Take extra care to water the mix rather than the leaves.
How are the plants doing?
Honestly? The results have completely blown us away. Seeds germinate quickly and evenly, and the plants grow faster than we're used to.
When the first reservoirs came out of the machine last year, we started testing immediately. That was around mid-July, and by early September we were overwhelmed with produce:
When the first reservoirs came out of the machine last year, we started testing immediately. That was around mid-July, and by early September we were overwhelmed with produce:
A larger test with a group of other MM gardeners was just as successful.
So we scaled up production and put the reservoirs in the shop in spring 2025. We also converted all our own raised beds and began sowing in March, with results including:
So we scaled up production and put the reservoirs in the shop in spring 2025. We also converted all our own raised beds and began sowing in March, with results including:
- a huge first head of Baby broccoli
- summer spinach that needed harvesting after four weeks
- healthy bush basil plants, all the same size
- excellent results from this year's test seeds
- more and larger strawberries
- fuller heads of pak choi
- Crispy leaf lettuce that quickly fills the entire square
- beautiful heads of cos lettuce
- and climbing zucchini plants that grow quickly and strongly, with the first harvest around late June
But of all the plants that thrive with water reservoirs, tomatoes are the undisputed winners. Every kind of tomato produces an almost unbelievable harvest per plant.
How good is that? More results with less work 😀
And we certainly aren't the only ones who are so enthusiastic:
And we certainly aren't the only ones who are so enthusiastic:
EllenL (MM gardener since before 2019)
I've never had such large, beautifully green, tender vegetables as I have in the raised beds with water reservoirs. And it's wonderful not to spend so much time watering any more.
Silvia (MM gardener since 2019):
I recently started using water reservoirs, and I'm delighted with them. They give me peace of mind because I don't need to water as often. I've also noticed that the leaves are larger, brighter and greener.
I recently started using water reservoirs, and I'm delighted with them. They give me peace of mind because I don't need to water as often. I've also noticed that the leaves are larger, brighter and greener.
Where do these reservoirs come from?
From our warehouse in Aduard 😀 We produce them ourselves from LLDPE powder sourced in the Netherlands.
We designed and built the machines ourselves too. It's quite a remarkable story.
You can read more about it here.
We designed and built the machines ourselves too. It's quite a remarkable story.
You can read more about it here.
So, now you know why we garden with water reservoirs
Better-growing plants and much more relaxed vegetable gardening.
These reservoirs are designed for our MM-Hero raised beds, and for the MM-bamboo raised beds we no longer supply.
They are not suitable for our older MM-original raised beds made from Douglas fir or poplar, or for any other wooden or homemade raised bed.
The profiles supporting the reservoirs carry an enormous weight: both the moist mix and the filled reservoirs, quickly adding up to around 200 kg or more.
Joints and screws in wood exposed to the damp conditions of a raised bed can come loose fairly quickly as the wood deteriorates. If that happens, the reservoirs and mix will fall, which can be dangerous with a table-height raised bed.
It can also happen in a ground-level raised bed and will certainly prevent the reservoirs from working properly. So don't do it.
These types of raised bed are therefore NOT suitable for the reservoir conversion kits:
They are not suitable for our older MM-original raised beds made from Douglas fir or poplar, or for any other wooden or homemade raised bed.
The profiles supporting the reservoirs carry an enormous weight: both the moist mix and the filled reservoirs, quickly adding up to around 200 kg or more.
Joints and screws in wood exposed to the damp conditions of a raised bed can come loose fairly quickly as the wood deteriorates. If that happens, the reservoirs and mix will fall, which can be dangerous with a table-height raised bed.
It can also happen in a ground-level raised bed and will certainly prevent the reservoirs from working properly. So don't do it.
These types of raised bed are therefore NOT suitable for the reservoir conversion kits:
Over the years, we've tried all kinds of ways to make watering easier. None of them worked well or easily.
- Upside-down bottles: you either have to refill them every day or they provide too little water
- Sprinkler system: gets the leaves wet
- Drip irrigation with tubes: a huge amount of work to connect and adjust, with tubes all over your garden. It's also much more expensive than our water reservoir
