Stone Wool

Stone wool is basically a wool-like substrate made from melting down rocks such as basalt and anorthosite and spinning it into fine fibres – producing a material with the texture of dense candy floss.

It’s used for a range of purposes, including soundproofing, fire protection and building insulation. You’ll sometimes hear growers refer to it as Rockwool, although that’s actually a brand of stone wool designed for insulation.

Horticultural stone wool is produced especially for growing, with a slightly different manufacturing process compared to industrial types. It’s the chosen media for the cultivation of medicinal cannabis, and also widely used in commercial agriculture — many of the vegetables on your supermarket shelves will have started out growing in a stone wool substrate.  And it’s just as useful a product for smaller-scale grows. 

Why does stone wool work so well as a substrate?

The textile-like structure of stone wool allows it to retain a substantial amount of water within its fibres, but drain off any excess water quickly. And as it’s inorganic, it maintains its absorbance and drainage qualities almost indefinitely.

That means there is constantly water in the substrate but never too much. This unique property gives your plants’ roots instant access to water while still allowing sufficient oxygen to circulate — through the air pockets. This balance ensures a consistent and even grow.

Compared to coco mix and soil, stone wool has the important advantage of being man-made, which means no risk of importing disease or pests with your substrate. Plus, it’s lower volume, and lighter weight, which makes it easier to work with from a practical point of view.

Stone wool doesn’t lock-up any nutrients, nor does it release any other unwanted substances into the nutrient solution.

Cultiwool is a brand of stone wool products developed to cater specifically for the hydroponics and medicinal cannabis industry.

The types of plants grown in hydro systems require two important factors in a substrate — uniformity and hygiene. Cultiwool provides both. The unique manufacturing process creates the perfect density and orientation of the rock fibres — holding an ideal amount of moisture while also providing the porosity needed to ensure air circulation within the blocks. And as an industrially produced 

substrate, Cultiwool is naturally pest and disease free out of the box.

Stone wool is a popular choice for propagation as it provides the ideal conditions for getting early root growth started.

If you’re growing from seed, your best choice is Cultiwool CRB plugs. You can simply place the seed into the plug, water it, and with the right conditions, you’ll see plants starting to sprout after just a few days. Once the seedling has grown to about 2 or 3 inches you can transplant it to a Cultiwool 3” or 4” block, an X-fibre slab or straight into the soil.

Cultiwool plugs are sized to fit perfectly into each other, so you can just drop a smaller plug directly into the holes in a cube the next size up — which means there’s no root disturbance.

If you’re working with cuttings, the process is slightly different. The best way to propagate these is to start off with a Cultiwool CRB plug, cut the plug in half, place the node of the cutting in the plug, hold the plug together and place it into a larger 3 or 4“ block — and then water it.

Once your 3” or 4” inch block is well-rooted you can move on to the next stage. If you’re growing in an NFT you’ll probably want to leave your seedlings in the CRB plugs. With other systems, like a dripper, you might want to drop the plugs into a Huge block, Big Daddy block or even the X-Fibre slabs.

NFT systems like the Gro-Tank and Multi-Duct are ideal to use with stone wool. You can cut the top plate to fit the size of your block — ensuring it keeps out the light and prevents algae from forming on the cube.

Alternatively, if you want to grow in a slab then the Origin Duo slab is ideal. It’s custom-built to house the Cultiwool X-Fibre slabs, and the drippers then feed the nutrient solution directly into the slab.

For an Autodrain or Origin system, Big Daddy blocks are ideal. And the 1cm Cultiwool mini-cubes can be used with any drip-fed or hand-watered system — simply add them to the pot like any other type of media.

If you’re ready to get started with stone wool, here are a few tips from our in-house team of horticultural experts to help you get the best results.

You’ve probably heard about growers using stone wool for propagation or as an alternative to other media in their grows. If you’re looking to start using stone wool yourself, but you’re not sure how it’s used, or why to choose it over other products, then you’ve come to the right place.
In this short read, we’ll explain how stone wool can improve your grow, and look at the main benefits of one of the market-leading products — Cultiwool.

Everything you need to know about growing in stone wool

Growing in stone wool

X-Stream Aeroponic Propagator

The key to successful propagation (as with most horticultural techniques) is careful preparation — which starts even before you take your first cutting. First, you need to ensure you’ve selected a healthy mother plant to take your cuttings from. Check that it’s disease and pest-free, and give it a generous watering the day before you plan to take cuttings to ensure it’s well hydrated.  

Once you’re ready to take cuttings, make sure you have a sterile working environment — clean your hands, tools, containers, and work surfaces thoroughly to lower the risk of introducing diseases or pests. Don’t handle other plants while you’re taking your cuttings, as there’s always the risk of cross-contamination.  

Speed is also key. Don’t rush the process, but equally, don’t take a cutting and then leave it sitting around unnecessarily while you get the propagator ready — this can quickly lead to the cuttings drying out and is a common cause of transplant shock. Make sure you have all your equipment prepped and ready to use before you start taking cuttings from the mother plant. 

When you take the cuttings, use a sharp knife or shears — using a blunt instrument will crush the stem rather than cutting it cleanly.

Cut at a 45-degree angle rather than straight across — this creates more surface area for the new plant to absorb water, oxygen and nutrients, getting it off to the best possible start.

Once you have collected all the cuttings you need, you can transfer them to your propagator. Using an aeroponic propagator like the X-Stream Aero will give you the best results, for a number of reasons.  

Firstly, its unique misting chamber gives your cuttings uninterrupted access to both water and oxygen. The misting action creates tiny water particles and the movement means that oxygen is able to circulate more freely around the roots.

This leads to the fastest root development possible — which allows you to transfer your cuttings to media and start the final stage of the grow sooner.  

This early development also reduces the risk of transplant shock — the cuttings will have stronger, thicker roots and the lack of growing media in the propagator means less risk of pests and disease. You’ll also have much better control over temperature and humidity levels. Propagation water should be maintained between 22°C-26°C — and the best way to ensure the temperature remains consistent is with the X-Stream Aeroponic’s optional water heater. 

On a practical level, it’s easy to check on the progress of your cuttings without disturbing the plants — which can be quite fragile at this stage — and you have convenient access to the pump and nutrient solution. Using the X-Stream Aeroponic, you should see roots appear within the first few days, and your cuttings will be ready to transplant into growing media within as little as 10 days. 

For the best possible results, check out the following tips from our expert team of horticulturists.  

Propagating plants from cuttings is one of the quickest ways to build your crop — and as the plants have a shorter growth period compared to growing from seed, you’ll be able to harvest sooner. But there are a number of potential pitfalls you need to avoid to ensure your new plants thrive.  

In this article, we’ll take a look at the key factors you should consider when propagating cuttings, and how using an aeroponic propagator like the X-Stream Aeroponic can give you the best chance of success. And as usual, we’ll finish with some top tips from our horticultural team to help ensure you get the best possible yield from your newly propagated plants. 

X-Stream Aeroponic: A sure-fire way to root even the most difficult plant cuttings. 

X-stream Aeroponic Propagation

Foliar Feeding

Well, the clue is in the name. “Foliar” means “relating to leaves or foliage”. So foliar feeding is supplying a plant with one or more nutrients through its leaves, rather than the more obvious method, through the root zone. 

However, it’s important to remember that foliar feeding isn’t an alternative to root feeding. Establishing a well-developed rhizosphere through root feeding is crucial to developing healthy plants—there’s no way around that. Foliar feeding is best used when you need to boost the nutrients your plant is already absorbing through its roots by using an additional delivery method.

Plants are able to absorb nutrients through their leaves via the stomata—the small pores on the underside of the leaf which they use to exchange oxygen and carbon dioxide with the atmosphere. Certain nutrients can also pass through the stomata, and be absorbed directly into the growing leaf.

The key to the process is moisture—without surface moisture, nutrient exchange is minimal. So in nature, foliar feeding happens mostly in aquatic plants, which absorb nutrients from the water in which they are growing.

Growers can create a similar environment for nutrient exchange by using a foliar feeding spray. The spray contains one or more nutrients but may also include a surfactant to wetten the leaves and improve the absorption rate.

The main benefit of foliar feeding is the speed at which nutrients are absorbed, and the direct route that they take. For example, if your plant is lacking nitrogen, causing yellowing leaves, then adding nitrogen is the answer. 

Doing this through root feeding can take days or even weeks to show results—it takes time for newly absorbed nutrients to travel through the plant. With a foliar spray, you can see improvements almost immediately, as the nutrients are absorbed directly into the leaves—exactly where they’re needed.

As with any growing technique, foliar sprays are most effective when used in the appropriate situation, and in combination with general plant care. Here are a few scenarios where foliar feeding can really make a difference to the health and yield of your grow.

Foliar feeding strengthens every part of your plants, from leaves to the root zone. It’s ideal when plants have recovered from disease or nutrient deficiency to revive and restore them. Used alongside an effective root feeding system to optimise root health, a foliar spray ensures that your plants are receiving the right balance of nutrients—and are able to make the most of them.

Foliar sprays are a quick and simple tool to deploy when you need to treat a short-term nutrient deficiency—getting to work much faster than a formula specifically designed for root absorption. 

They also allow you to target individual plants in your grow which need additional nutrients, rather than treating your entire grow at once. 

But don’t rely on foliar sprays as a remedy for masking long-term deficiencies—in these cases, there’s usually a bigger issue that needs to be addressed. 

Foliar feeding is particularly effective in younger plants, so using a foliar spray on cuttings that have just rooted is a great way to give them an initial boost and encourage sustained growth.

For the best results when using foliar feeding, check out the following tips from our in-house team of horticultural experts. 

If you’re new to foliar feeding, we’d recommend you try 

 to get started, as it’s a strong all-around foliar spray. It’s easy to use, but also popular with many of our more experienced growers as a solid product to keep on standby for any emergencies. 

 is a blend of four natural products— catalyst, veg boost, biowetter and wetting agent—all in one easy-to-apply pH-neutral spray with no need for mixing or adjustment. It’s optimally formulated so your plants get the right amount of nutrients, but in a more dilute solution than you’d use for root feeding—avoiding the risk of nutrient burn on the leaves. 

The misting nozzle ensures an even distribution of nutrients onto the leaf surface, which increases the speed and volume of nutrient uptake. Additionally, the proprietary wetting agent reduces the surface tension of the solution—increasing absorption and further minimising the risk of leaf burning due to artificial lighting.

Plants don’t just absorb fertilisers through their roots—they can also absorb key nutrients directly through their foliage. For growers, knowing when and how to use foliar feeding is essential to protect the health of your plants, and maximise yields. In this article, we’ll break down some of the dos and don'ts of this type of feeding to help you get the most out of the technique.

Foliar Feeding: How It Works & When to Use It

Interview With House & Garden

 House & Garden was founded by William Van De Zwaan in 1990. A third-generation biochemist, he took his grandfather’s A&B recipe for tulips, roses and carnations and modified it for our market. And in the following years, he developed the rest of the line to what we know it as today.

 In 2015, the founder was ready to move on, so we relocated our manufacturing facility to Humboldt County, California under new ownership. The current owners were actually the same team that introduced the House & Garden brand to the United States market. So there was a long-time relationship in place and therefore the trust that the transition would honour the brand and maintain its stellar reputation.

 I joined in 2017, and was really amazed by the painstaking detail we took here in the US to make sure the manufacturing was the exact same as it had been in Holland and the way we maintained continuity and kept that quality. We shipped everything from handrails to stairs from the manufacturing facility in Holland and rebuilt it so it was exactly the same, it was pretty amazing. The lead mixer from Holland came to the US for a full year to train our staff on the products too!

So Are The Products Still Exactly The Same Today As They Were When You Were Based In Holland?

 A lot of people worried that the recipes would change when House & Garden moved to the U.S. People already relied on and loved House & Garden products and didn’t want anything to change. We loved House & Garden products too, so none of us wanted anything to change either! We kept all the recipes, raw materials, and mixing processes just the same. And we had the lead mixer from Holland on-site to ensure we did everything exactly as they had done in Holland. And since our manufacturing process is designed for small batch mixing, we have more control over quality and consistency than other brands on the market. Combine that with our quality control laboratory, and we’re in a position to provide top-notch quality and consistency. The only change has been the innovation and addition of some exciting new products like Magnesium Boost.

LET’S GO INTO YOUR PRODUCTS IN A BIT MORE DETAIL…

Roots Excelurator Is The Most Well-Known, The Biggest Seller. Can You Give Us Any Hints And Tips On How You Use It In The States?

 We use it at 0.3ml per litre all the way through veg into your third week into flower, longer if you have a longer flowering period. Something a lot of people don’t know is there’s an enzyme in it that helps to cure root rot. It’s definitely a game-changer if you’re in hydroponics or have a really wet growing medium. It kills off the dead roots causing new root hairs to grow which a lot of other root stimulants don’t do. The proofs in the pudding: trial our Roots Excelurator against another root stimulant, take two cuttings side by side and in a couple of weeks you’ll see the root hair, the actual root structure, that’s when you see a real difference. Also, you’re not going to get a root stimulant for the price that’s that good and concentrated.

 A big sales point for Roots Excel is that you can use it on your clones and cuttings to get faster roots.

Another Top Product In The Range Is Amino Treatment, It’s Perhaps Less Well Known Than Roots Excelurator. Can You Tell Us More? 

 Amino is a really special product. The ingredients of the product have always been kept quite secret at House & Garden. It took even us a few years before we were allowed to know what was in it! Amino Treatment offers three products in one, including amino acids, humic acids, and an extremely plant-available form of silica. A lot of companies would rather sell you these ingredients in three different bottles! Amino Treatment brings a great value by supplying all three ingredients in a single bottle, and our blend is optimized specifically for our favourite flower. Having the silica mixed with amino acids doesn’t mess with your pH like a standalone silica product does. With that you put the stand-alone silica in your reservoir first then adjust your pH, as this is mixed with amino acids, you can add it to your reservoir at any point without the pH being messed up. It helps calcium uptake, stress relief, helps all your macro and micronutrients and it’s a really neat product – my favourite product of all most definitely!

Moving On To Another Product In The Range, Multi-Zyme. How Does It Work?

 You use it all the way through veg and the third week into flower, but the main benefit is it’s breaking down all of your dead root material and making it available to the plant. There are a lot of other enzymes out there that use 3–4 times as much and are usually 3–4 times more expensive. Like all our products, ours is highly concentrated.

What About Bud-XL? What Are The Main Benefits?

 With Bud-XL, you can see the difference between using it and not using it. I did it a few times just to see the difference using the same plant and same cuttings and it makes a major difference! It’s our carbohydrate boost and it contains an enzyme that takes all the sugars in your sugar leaves on the outside of your flowers and locks them back into the flowers so they don’t get wasted. Basically, your plants’ creating all these sugars and Bud-XL’s like “hey we made all these sugars I’m not gonna waste them” and it brings them back into the flower site and that’s when you get that flavour and aroma. It really makes a big difference in the overall quality of the fruit. It comes in about week 4 or 5 in the flowering period depending on the plant and that’s once the flower sites have already started forming.

 Stand-alone I would say Bud-XL is essential because you do see that difference, really showing off what the plant is capable of, whereas a lot of carbohydrate products on the market get complaints that they make all plants smell the same or give a flavour that isn’t natural. Part of our philosophy is to naturally accentuate the plant’s true potential, so the finished product can be a little more complex, a little more true to what it’s been bred to be.

Shooting For Success: What’s The Difference Between Top Shooter And Shooting Powder? 

 Top Shooter is just a liquid version of Shooting Powder, there’s no real difference. We had hydro guys who didn’t want to deal with powder so we created a liquid version. You use it in the last 3 weeks before you flush, it’s superior to other big finishers because they take about 3–4 days to break down the particles and for the plants to get all the phosphorous and potassium. Shooting powder is instantaneously available to the plant, that’s what makes it such a different product because you use it and 24–48 hours later, you noticeably know you’re using shooting powder. It also triggers a second set of flowers that come in and push the flower to its fullest potential in size.

 Shooting powder is also sieved into a superfine powder for better bio-uptake in the plants.

The reason we don’t do it in big tubs is because you can maintain quality control. With big tubs you can get moisture and start to lose quality and with it being opened and closed it can be affected by humidity. Having it in smaller sachets ensures you’re getting the same quality of product every time.

Would You Feed Different Varieties Different Ratios? 

 It’s down to knowing your plant, everything’s going to be different. Some plants are heavy feeders some are not, so it’s making sure they’re not starving and not overdosing, they’re just happy.

 For varieties that require extra magnesium, our Magnesium Boost product provides all the additional Magnesium needed to keep the plants healthy and the leaves green. Varieties that are bushy and have a lot of leaf canopy are more likely to require this. They’ll tell you if they need more magnesium. You’ll start to see yellowing between the veins in the older leaves. Plants held in vegetative states for longer than a couple weeks will benefit from the additional nitrogen provided by our Nitrogen Boost product. And if you’ve noticed that your variety is sensitive to high EC (electrical conductivity), I’d recommend playing it safe and feeding Top Shooter/Shooting Powder and Top Booster at half strength. It’s a safer bet to slowly add more over time than to risk damaging sensitive plants by pushing them too hard.

 Yeah, we’re running trials and we’re always innovating, which is exciting, but that’s all we can say for now…

Why Should Growers Choose House & Garden? 

 The high concentration levels, we only put just enough water in our bottles to make them shelf-stable, a lot of people have a lot of water and that’s why they have higher dosage rates. Secondly, a lot of companies don’t have the same quality control, if our product is 0.01% off, we won’t bottle it, so you’re always getting the same level of quality. Those are the key factors, you get quality and consistency with House & Garden.

 Another thing that’s unique is that we drive to bring out the authentic tastes and quality and we’re focused on maximising a plant’s potential versus pushing all plants similarly and compromising on taste and quality.

We caught up with the product specialists to give us insight into House & Garden’s key products.

Interview With House & Garden: The lowdown with Casey & Nate

Articles

Our team of horticultural experts are on hand to bring you the latest growing advice.

Got any questions? Don't hesitate to contact us here.