How compact should potting mix be and what should be used.

[Richard Hole]

Hi



How tight do you suggest packing the potting mix for Nepenthes? I always thought it had to be packed as tightly as possible. However, I read today that if pure sphagnum moss is used, it is best to have it a bit loose. See http://www.omnisterra.com/botany/cp/list/cp99all.d/0327.htm



An advantage of not packing it too tightly is that a bag of sphagnum moss would fill more pots and the cost per pot would be less. However, if it is too loose, the roots may get disturbed if the plant is bumped and the potting mix may not be in good contact with the plant.



If a bag or a hand-full of moist sphagnum occupies a certain volume (x) when it is compacted in a pot as tightly as possible, how many times greater a volume would you suggest it be compacted? Would double the volume of the tightest compaction possible be too loose?



I was thinking of using pure coir chip for a potting mix as it is cheaper than sphagnum moss, but some people say it has problems and it can contain salt if the coconuts are grown near the sea and the coir has not been leached well with water.



I would like to use pure sphagnum moss. However, it is a bit expensive if it has too be packed tightly. I have read that Perlite can be a health hazard if breathed in or handled so I prefer not to use it. A pure medium (for example 100% sphagnum moss) would have the advantage of saving the time to mix a potting mix up.



Any suggestions for a good mix would be appreciated. If you suggest one, please indicate if you have tested the plant growth rates against other types of mixes.



Your help will be appreciated,
Regards Richard.

[arvin555]

Richard,

You posted this in the Propagation topic, so I take it that you are asking about potting mix for propagation? Then again it might not be too different between propagation mix and cultivation mix.

My two cents:

I tend to keep the propagating medium very moist so cocopeat or sphagnum moss are usually very moist and thus settles a bit compact. I haven't really tried coco chips for propagation.

As a rule of thumb though I do not really go out of my way to compact my potting mix, after putting them in a pot, I water them until soaking wet and then let them drain, after excess water is drained I am ready to use it. And usually it is compacted enough to hold the cutting in place.

If your question is for cultivation, almost the same thing, when I repot, after I put the usually moist new potting mix, I then tap the pot on the floor a bit, put some more and then water the whole pot till soaking wet, let drain and that is it.

Lastly, if potting for cultivation, please be reminded that some neps like it very loose and airy while others like it a bit more compact. ie. veitchii like loose and airy and well drained, while ampullaria likes them more compact. That is why for veitchii I use coco chips and for ampullaria I use coco peat.

I have stopped using dried sphagnum moss as pure potting mix for nepenthes.

Hope this helps.

TTFN
Arvin

[Richard Hole]

Hi Arvin and other growers,

Thanks for the letter.

In the last post I was referring to repotting Nepenthes plants in general and not only propagation. I could not find a more suitable category to post it under. Perhaps the forum could add a section named “Cultivation” in the Nepenthes section.

I just potted my cuttings two days ago using pure sphagnum moss and I packed the moist sphagnum as tight as possible by squashing as much of it in the pot as possible and pushing it down with my fingers. However, since then I read Nepenthes like a looser mix.

I would like to know some approximate figures from you and other growers on how compact the mix should be. To work this out, what you can do is fill a pot or a measuring cup with moist potting mix and compact it like you normally do after potting the plant. Then note the approximate volume. Then once you have done that, press the potting mix down with your fingers as hard as you can. Then, could you tell me approximately what percentage of the original volume it now is. Please also indicate what the potting mix you are referring to is. You may want to try and measure the compaction of some other mixes or pure mediums even if you do not use them. For example, pure sphagnum moss which I am thinking of using. It would be good to know the loosest the potting mix can possibly be compacted to produce successful growing results. This is because that would work out more economically cost wise as a bag of potting mix would then enable potting more plants. Also, it could save time as the compacting would take time. So it would be good if a number of growers on the forum could measure how much they compact their potting mixes. You could give figures for both propagating cuttings and potting mature Nepenthes plants. This could help a lot of people and save costs and produce better growing plants.

Also, Arvin, why did you stop using dried sphagnum moss as pure potting mix for Nepenthes?

Your help is appreciated,
Regards Richard.

[arvin555]

Richard,

I'm hoping that other members will chime in here, my experience and information is just one side, there are many sides to be had, so hopefully people will start posting.

I think however that you posted this in the wrong place... you should have posted it in the main nepenthes topic here: https://forum.petpitcher.net/forumdisplay.php?f=6 that is where general discussion about nepenthes is, scroll down and you will see all the different topics, the first few ones you see in that page are forums like propagation.

Maybe the admins can help us move the topic later, meantime I will reply.

1. Gosh your request sounds like you are trying to make a scientific study of the compactness of potting mix. Which is all good, but unfortunately I don't think I'll have time to do it, because what you are being like is a Baker... very precise, while I am like a chef... all by taste and feel. Meaning, I don't really study the compactness, I just do what I do as mentioned above. If after soaking and draining the mix I find that the pot needs more potting mix, then I add more then soak again and drain again

Also as mentioned, different species live in different substrate in the wild, some live in clay like soil, some are epiphytes, some in bogs. So again it depends on the species.

2. Why did I stop using Sphagnum moss? Well first of all they are hard to find in my area (Philippines) very difficult to buy from stores, so I am using them only for bog plants, VFTs, droseras. However that is not the only reason. I find that if I am careless and forget to water the plant or plants, the sphagnum moss can dry out and when they dry out they need to be soaked again or else they tend to not be able to retain moisture. I have killed a plant because I let the mix dry out too much and didn't know about it, so even if I was watering the water would quickly drain out. So now I usually put even my neps under a water tray... and if I do this with Spag moss, the mix will be too wet and boggy and not ideal or nepenthes either.

So I use now cocopeat and coco chips, if the species likes a more moist and compact mix, more cocopeat in the mix or pure cocopeat. If it likes airy mix, then more cocochips. Sometimes I include pumice rock in the mix too.

Lastly please understand this is just how I prefer to pot my neps, I don't claim that this is the best or ultimate way to pot neps, but the system works for my gardening habbits and situation

TTFN
Arvin

[NepNut]

How compact is compact?? I would gauge this by how well drain the media is when you water it, you all should know what I'm talking about right?

Only a handful of neps species (all L/L) preferred (or adpatable) to water soaking media and those can also be grown equally well in well drain media. Most other neps prefer media that can hold moisture and well drain (more to do with giving circulation to the media and root zone).

Try to introduce some other potting mix that's chunky (1-2 cm) like perlite, coco chips, orchid bark, charcoal and etc when mixing LFS to "open" up the media. With this, you'll be able to use less LFS. If you want the media to retain more water, you just adjust the ratio of LFS (use more) or mix it with peat or coco peat.

Myself use mostly inorganic media like coarse sand, burnt red clay (laterite) and perlite/pumice with up to 70-80% of the media composition. The other 20-30% will be mainly organic based media like coco chip, coco peat and LFS (to be use mainly to increase water retention of the media). For hanging pot, since most inorganic media like sand and clay is heavy by density, you can increase the ratio of less dense inorganic media like perlite and pumice to lessen the weight of the pot for hanging. Same effect can be archieve by increasing the ratio of coco chips but please becareful with using a lot of coco chips in your media if you're growing your plants outdoor in a tropical country that may experience seasonal monsoon rain...

There's no "perfect" media that you can get by following other's mixing ratio and type of media... you will need to play around/adjust your watering frequency, growing condition, type of pots and various other factors to strike a balance to get that "perfect mix" that will just only work for you and you only... it's magical.

Hope this help.

[Richard Hole]

Hi

Another way to measure compaction is to put the loose potting medium into a pot or measuring container in as loose as manner as possible. Then measure what the volume is. Then once you have noted that, compact the medium like you normally would when potting the plant. Then measure the volume again. Please let me know what percentage of the original volume the medium is compacted to if you measure using this method.

If the medium does not have to be compacted much, pure sphagnum moss may be the best way to go as it holds the moisture and would mean the plants need less watering which would save time and water. Also, a pure medium would save time having to mix many things together I am not sure if anyone has proven that other mixes produce better growth rates in Nepenthes. If so, please let me know.

Also, NepNut, what do you mean by "LFS"?

Your help is appreciated
Regards Richard.

[arvin555]

Now I remember also one other reason why I stopped using Sphagnum moss (pure) as potting mix. As Nepnut mentioned in his last sentence, it all depends on your watering habits, if you water often or have no time to water often. etc.

With Sphagnum moss, if I water often, or put a water tray it gets too moist and sometimes even become quite anaerobic... you can smell the stink. So I stopped using it. My style is to use water tray with just shallow water on the tray, coz I don't get to water often. At least that works for me.

If Sphagnum moss is always wet or if you are always watering, you will surely find that it compacts over time.

Another thing, cocopeat... is probably a bit more environmentally friendly or at least more sustainable than sphagnum moss.

TTFN
Arvin

[Richard Hole]

Hi Arvin and those interested,

I heard that coco chip is better than coco peat as it allows more air in the soil. I also read you need to be careful it is not sourced from trees near the sea unless it has been well leached with pure water as otherwise it can contain salt.

I remember Adrian Slack who wrote a large detailed book on carnivorous plants said to never water Nepenthes using the tray method. However, your conditions are probably different.

I was not thinking of using a tray for Nepenthes. Instead I planned to water from the top about once a week in average weather conditions. I read a tray watering method is best for other carnivorous plants.
Pure sphagnum may then be best for me for Nepenthes. If you come across any proof that other things are better, please let me know.

Your help is appreciated
Regards Richard.

[NepNut]

Hi Richard,
LFS is simply an abbreviation for "Long Fiber Sphagnum".

I see one problem the way you measure the volume this way. If you're using only LFS, then it's ok. But if you're mixing media of different weight and sizes, it's won't be accurate since every susbtance had it's own density.

What I meant to see how compact a media is by looking at how well drain the media is, it's simply to see how fast the water will drain out of the pot when you water it (not scientific but fast and practicle). If you water the pot and the pot just flush out from the bottom right away, then it's consider very well drain and not compact. If you water the pot and it took 30 seconds to 1 minute to see the water slowly trickles down, then it can be consider compact media with high water rentention quality.

If I were given only 1 choice to choose, I will always go with LFS as the preferred media. Due to other issues like Arvin pointed out using LFS, I would like to cut down the usage if possible. I think most people woould agree LFS is the best media to be use for most CPs but the problem is the high cost for good quality LFS, mainly originated from New Zealand. That's why people are trying to find alternatives, which is more sustainable and cheap... Coco media is actually a by product from the coco related industry and it's available abundantly in most tropical countries.

Another issue with using 100% LFS is when you grow your plants outdoor without shelter from rain in tropical countries. If it's monsoon season, you will get non stop raining for days, the 100% LFS media will be too wet and cause rotting in roots. That's why I have to mix the media and use pots with good drainage and ventilation so that excess water in the pot will easily drained out and evaporated.

There's no right or wrong choice to use what type of media but more importantly what media that suits your gorwing environment and your habit. The only concern I have of using organic based media, it's the fact that sooner or later, it'll break down. But maybe that's just me because I'm lazy... or maybe the thought of repotting hundreds of pots every 6 months to 9 months it's just too much .... LOL

You mention you planned to water only once a week? I'm guessing you're keep your neps in an enclosed area?

[Richard Hole]

Hi



Yes, I grow my Nepenthes in a greenhouse so that the rain does not water them.

I thought pure sphagnum may be the best and safest way to go. However, you could still give an approximate figure for the compaction rate of a potting mix by mixing it up first and putting the mix in a pot loose and then measure the volume and then compact it like you normally do when you pot your plants. Then you would measure the volume again. That would give a reasonable indication. Any figures would be appreciated.



Do you know anyone that has used polystyrene foam in the potting mix as asked in my other question on the forum?



Your help will be appreciated,
Regards Richard.