S/H giving up

[Joseia]

Originally Posted by RosieC

I first noticed that Leca I had used before was liked more by the plants than new stuff, and that plants left in new stuff for over 6 months of watering with rain water and very weak fertiliser would suddenly settle in and start liking it. This is when I realised that it needed better washing before use. I understand Primeagra to be much better for that than other makes though, I wish I lived in the USA and could use it.

Yes, I think pre-washing is very important. This time, I soaked the Primeagra in RO water, drained, rinsed and soaked it every night for two weeks. I have been growing moss on the Primeagra for 2.5 months and there is absolutely no sign of mineral/salt buildup, and the moss is thriving.

[WaterWitchin]

Originally Posted by RosieC

Joseia you are probably right about water quality, especially as you were seeing salt build up.

I've had that problem and with other brands of Leca which are not as clean as Primeagra you can also get salts leaching from the Leca until it's been washed and washed and re-washed. With pure rain water I was still seeing salt buildup until I realised this. And as you say... the new roots hate it.

I first noticed that Leca I had used before was liked more by the plants than new stuff, and that plants left in new stuff for over 6 months of watering with rain water and very weak fertiliser would suddenly settle in and start liking it. This is when I realised that it needed better washing before use. I understand Primeagra to be much better for that than other makes though, I wish I lived in the USA and could use it.

---------- Post added at 10:55 AM ---------- Previous post was at 10:46 AM ----------



Yes, that's how I kept them alive the winter I had them in S/H. However I only had a couple of Phals in S/H then, I was looking for a growing method that would work for all 20+ phals and having to provide heat mats to that many on windowledges was not practical so I stopped using it for Phals.

I only use S/H on orchids which can cope with the lower temps now (such as Oncidium types and Phrags).

Not wanting to hijack another's thread (floradude's), but a query... I don't understand the difference in TDS when using bark or LECA. I have super-hard water, but still use it straight from the tap when short on time. I think the "crustiness" of the hard water shows up more rapidly on LECA than it does on the bark, but isn't it still the same thing? Just that the bark/mix doesn't show it up, but orchids are still getting the same TDS regardless of media used?

RosieC... I had same problem. Am experimenting now with a DIY heat mat using rope lights. Will let you know how that goes.

[RosieC]

It does seem to accumulate more on Leca than on bark with the same water, I've noticed that too. I have a sort of concept it is due to the rate at which water evaporates. But I'm guessing on that.

I think it's the accumulation that is a problem to the roots, not the amount in the water (which just washes past them if not accumulating. When accumulated it is held closer to them for longer. But again I'm sort of guessing there.

---------- Post added at 02:23 PM ---------- Previous post was at 02:19 PM ----------

I've merged two threads this one, and the one where floradude said "Thanks for the feedback" and Ray and Tucker posted.

It's best to have everything together as one conversation I think. I, and possibly others had missed the response.

---------- Post added at 02:25 PM ---------- Previous post was at 02:23 PM ----------

Originally Posted by Ray

Keep in mind that the phals are going to need a LOT of watering if grown in traditional culture using LECA or lava rock. The use of plastic pots can slow the drying of the medium.

Ray is right, but I grow a lot of my phals this way. Leca, but not S/H. They need much more watering that the ones in bark, but at the same time I can water without having to worry about rot.

[WaterWitchin]

Well, yes, I certainly had missed out on part of the conversation.

And I think the mineral buildup is still "there" with bark, but we just don't see it as well. Perhaps we'll be fortunate to have Ray chime in on this?

[Ray]

It's all due to wicking.

In any pot, the evaporation of the water from the medium is primarily from the top surface, with some at the pot wall/medium interface. A clay pot extracts the water from the medium and transfers it outside, but the principle is the same.

Most organic media components absorb well, but don't necessarily wick so well - especially bark - so the particles more-or-less dry out independently of each other. LECA particles, because they tend to wick so well, try their best to equalize the moisture content of the pellets throughout the pot, so that results in "pumping" the liquid upward to the driest particles.

As a particle dries, the dissolved solids precipitate. With bark, the amount is determined by the amount of absorbed water, how dry it becomes, and how frequently your rewet it. With LECA, it depends upon the amount of absorbed water (which tends to be more), the amount pumped up from neighboring particles, how dry it becomes, and how frequently your rewet it - resulting in greater transfer of dissolved solids, hence faster buildup at the surface.

[RosieC]

Thanks Ray.

[Pilot]

Originally Posted by floradude

Thanks for the feedback....all worthy comments.

I live in Mexico at an elevation of 5,200 feet. It is a semi arid plateau (most all of central Mexico). Except during our rainy season the humidity is low.
I got into S/H when I decided to not grow in bark any more. For one thing bark as you know it in the USA is a no go here.
I tried coconut husk pieces and the orchids loved it. The problem was it broke down too easily with the resulting root rot. This is when I started on S/H. S/H introduced me to Hydroton. Even though I am leaving S/H it is full speed ahead with hydroton. I am growing all my Cattleya alliance types in 100% hydroton, and slowly converting my Phalenopsis to the same. I like the product and so do the orchids. The dendrobiums have been in red lava rock but Hydroton works also.

I think I may have some legitimacy here with the arid environment and the altitude. I grow my orchids at 6800' in Colorado. Trust me when I say I get arid... i also get having a hard time finding the right media for growing your plants.

Hydroton is great but in the end, it is hydroton in the sh form that did it for me. Introducing a plant that is growing new roots is so important but bottom heat made the difference for me. Getting them to transition without bottom heat is possible but more difficult which may explain the failure of sh for you.

I hope you don't give up on sh completely because it has worked so well for me before that for those of us with similar situations, it is God-sent!

[WaterWitchin]

Thank you very much Ray... knew you could explain it. And even so it makes since to me. The "pumping" it up part was my missing piece of knowledge. And I guess for me, also more frequent watering in S/H, thus more particles.

I concur with the heat beneath part. When I commenced, it made a world of difference in both phals and cats... and especially when first transferring over to S/H.

[Ray]

Actually, if your growing conditions are such that the top surface of the medium doesn't dry out (i.e., good humidity, mostly), then mineral buildup will be held to a minimum.

[WaterWitchin]

Wish I could achieve that perfect mix, Ray, but thus far it avoids me in winter. I use my office, which is also a sun room, for orchids in winter months. Have yet to get the right balance between ventilation and humidity.

Could keep them in the basement under lights, or in a spare room upstairs that's larger. They'd all likely be happier, but I wouldn't. I enjoy having them right next to my desk, where I can constantly look over and see the blooms. Just selfish that way.

Perhaps I'll try moving my fan again. And it reminds me, I was going to experiment with leaving more water in the trays by plugging the drainage holes when not watering.

This means I should also probably bring in a roll of paper towels, so the next time I water and forget to unplug the drainage, I'll be prepared.