About substrates that is! Along with feeding my plants regularly, I have noticed a vast improvement in my plants overall health and root health since I have been experimenting with substrates and finding what really works for the plants in my home environment.
I will give you a little back story on how I became so passionate about substrates. When I first started caring for plants, I was finding root rot was becoming a real issue for me and I thought it was from over watering. I did some research and started adding things into my potting mix to aid in drainage and aeration. I found the soil drained away the excess water and dried out quicker between waterings and my root rot issues started to become a lot less frequent! Fast forward a few years, a lot of trial, error and further research, I had figured out 2 mixes that really made my plants thrive and that's what I have been using ever since! (and am now sharing with you, our WV premium houseplant mix & our WV Aroid and Hoya mix) and with our more recent additions of our WV Growpole Blend & WV Cacti & Succulent blend, which were tried and tested behind the scenes as well.
Through all this experimenting and research I learnt a lot about the different substrates, so I thought it would be handy to put it all in blog post for you to reference. If we have the substrate on our website, I will link the product page on each substrate title so you can read a more information on that specific substrate.
POTTING MIX (STANDARD MIX) - The kind you get in places like the hardware store/garden centres) Now on its own, I personally think it is not free draining enough for the types of plants we grow as houseplants and for our indoor conditions BUT it does make a fantastic base, which you can then add other substrates to, to create an optimal mix for your plants. Potting mix is good because it contains & holds nutrients and water well, which obviously help our plants to thrive, but drainage and aeration is just as important for root health and development. Some standard potting mixes are better than others, so be sure to read the labels before purchasing. Some are heavily peat based, which is not an environmentally friendly additive. Some also contain slow release fertilisers and wetting agents (wetting agent is something that helps the soil absorb water when watering and reduces the chances of the soil becoming hydrophobic (water repelling). When choosing a potting mix as a base, I like to look for ones with minimal additives, or ones with some drainage aiding additives, like orchid bark or perlite/pumice.
PERLITE - Perlite is essentially expanded glass that is retrieved from areas where a volcano has been active. It is then heated, which it "pops" like popcorn into the light-weight, white particles we know as perlite. It makes a fantastic, cost effective addition to potting mix to aid in aeration and drainage, as well as keeping the mix light-weight. Over time, perlite can eventually float to the top of the soil as you water your plants because it's so light, which is why some people opt for pumice as an alternative, but this tends to make it a lot heavier, it is really just down to personal preference. Plants shouldn't stay in the same pot and mix long enough for this to ever be a real problem however.
FERNFIBRE - The holy grail of substrates (in mine, and a lot of others opinions) It is made from the Dicksonia fibrosa tree fern and is sustainably harvested from Government owned land, which is gathered via helicopter to minimise the disturbance to the surrounding areas. Fern fibre is a natural, long-lasting, fluffy and fibrous material which makes an amazing addition to a potting mix, or it can be used as a potting medium on its own. The fibrous nature of fern fibre makes it a fantastic propagation substrate as well, it retains the optimal amount of moisture while also allowing air flow to the developing root zone. Because Fern fibre is a long-lasting substrate, it can be reused over and over again (as long as you don't have any pest or disease issues)
It is a bit of an investment substrate in terms of cost but it is one I will always HIGHLY recommend and will ALWAYS use. I have a full BLOG post dedicated to Fern Fibre if you'd like to read more click here
ORCHID BARK - There are a few different types of orchid bark to choose from. Some are ungraded, non uniform and contain potting mix, while others are clean, graded and contaminant free. I personally like to use (and stock) the clean graded form of orchid bark, as you know exactly what you are using and can choose the right grade for your needs. Our Kiwi Orchid bark is made from Pinus Radiata, and is hard, long-lasting and uniform shape. It can be used on its own as a substrate to grow Orchids, it can be mixed with fern fibre to grow Orchids or it can be mixed into a potting mix to aid in drainage and aeration. Orchid bark also makes a great addition to a soil-less aroid mix. Some people also use it as a grow pole filler substrate, as it is as close to a tree as you can get indoors.
SPHAGNUM MOSS - NZ Spagmoss is a high quality moss, harvested from swamplands on the west coast. It is a renewable resource, as it can regrow and be harvested again in the future. Once it is hand harvested, it is then air dried (and sometimes compressed) ready to use. Spagmoss is loved by many house plant enthusiasts because of its wide range of uses. It can hold 20x its weight in water, so makes an ideal propagation substrate, grow pole or moss pole filler, growing substrate or an addition to a potting mix to help retain moisture (like an aroid mix)
The key when using spagmoss, especially as a propagation substrate, is to not pack it in too tightly, there needs to be air flow around the root zone, this helps reduce the chances of rot. Spagmoss can also be reused many times.
COCONUT CHIP - Coco chip is a by-product from the coconut industry and is a sustainable, renewable resource. It is used as an amendment to potting mixes to help aid in aeration, water and nutrient retention as well as providing some extra drainage. It is best not to use coco chip as a sole substrate for prolonged periods of time as it can potentially lead to nutrient lock, where it absorbs nutrients away from the plants (this also depends on the quality of cocochip you use). It is best to use it mixed in with other substrates and provides excellent benefits when done so. It is one of my personal favourite substrates to use in my mixes and I notice plants roots really gravitate towards it. The high grade we stock is also pH buffered.
LECA - Leca is used for semi-hydro growing and stands for lightweight expanded clay aggregate and is created in kilns through a high heat process, making them very lightweight and airy. Perfect for wicking up water and allowing plants roots to grow through them. It is a very popular substrate to use and can be used for a wide variety of plants such as peace lily, Alocasia/Colocasia, Hoya, Anthurium, Philodendron, Pothos and Monstera, just to name a few! It does require a bit of prep work to be done before you can start using it (see leca product page for a more detailed description of this). You can use leca in self watering pots, nursery pot in a cover pot or glass jars, there just has to be something that can hold water as the water reservoir for the leca to wick the moisture up to the plants as they need it.
PON - is also used for semi-hydro growing and is composed of three or four high quality ingredients (depending on brand). A premium slow release fertiliser (which feeds plants up-to 6 months after planting (in Lechuza) Zeolite, which is a microporous mineral that has excellent moisture absorbing properties and also stabilises pH levels. Lava rock, which supplies plants with a permanent supply of iron and aids in aeration, and lastly washed pumice, another highly porous ingredient that helps with absorption of water and excess fertiliser as well as providing aeration. Being a mineral based substrate that is completely soil free, means it has the perfect air to water ratio, 45% water - 55% air, which is optimal for plant growth, reduces the risk of diseases and prevents fungus (and the pesky gnats that can go along with it!) It is a fantastic substrate for growing plants such as peace lily, Alocasia/Colocasia, Hoya, Anthurium, Philodendron, Pothos and Monstera, just to name a few! You can use pon in self watering pots, nursery pots with a cover pot or glass jars, there just has to be something that can hold water as the water reservoir for the pon to wick the moisture up to the plants as they need it.
BIOCHAR / HORTICHAR - Biochar is a charcoal-like substance that is made from burning organic waste material from the likes of forestry and is such a fantastic additive to a substrate mix. It can help improve plant health by neutralising acidity in the soil, improve aeration and drainage and also provides some nutrient and water retention. Biochar is full of microscopic pores, which is what makes it so fantastic at holding onto moisture and nutrients, but it also provides a habitat for beneficial soil microbes. Another benefit is it can also absorb any nasties in the soil, keeping soil "fresh" and filtered. Our Wildvine house plant blend has this added in already but I like to also add it to my Hoya and aroid mix when potting up my plants.
WORM CASTINGS - aka brown gold :) Worm castings is a by product from worms also known as vermicast and essentially is a fancier term for worm poop. It is full of organic nutrients, so when added to potting mix or soil, it slowly degrades, releasing nutrients into the soil for plants to then absorb. It has no smell to it, making it a fantastic additive for indoor plants. You can either sprinkle some over the substrate of already potted plants or mix it into new substrate when potting up. Because it is a natural, organic and slow release plant food, there is no specific ratios you need to keep in mind. You can add as little or as much as you want, very user friendly! I like to use about 2 tablespoons for a 15cm pot as an example.
PUMICE - Pumice is a type of extrusive volcanic rock, which is created when lava with a high content of water and gas erupts from a volcano. The lava becomes frothy as the gas escapes and once it cools and hardens it creates the light rock like material we know as pumice. Similar to perlite, it helps aid in drainage and aeration in a mix but because pumice is heavier than perlite it can help weigh down a mix and stay more evenly distributed throughout. Pumice can be a little "dirty" straight out of the bag so when using it is a good idea to rinse it first ( but definitely not essential to do so.) Pumice is pH neutral and has great moisture retaining abilities so can be used as a propagation substrate for the likes of Hoya, Peperomis and Begonia or even as a semi-hydro growing substrate. It is generally inert, meaning it doesn't contain any nutrients so you will need to feed any plants growing in straight pumice.
When it comes to mixing your own potting mix, there really isn't too much that can go wrong, eyeballing ratios is totally fine! It is such an enjoyable part of the plant hobby, so just have fun with it. I hope you find this resource helpful and as always feel free to leave any comments or questions you may have below and I will be sure to get back to you.
~Kate
P.S ~ There are other substrates I haven't touched on here, but they are much less common/not as popular here in NZ. The ones I have mentioned are used most by plant enthusiasts and are readily available/easy to find.
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