Flushing S/H - Do you leave plain or fertiliser water in resevoir?

[RosieC]

This has struck me several times over the last months while flushing S/H pots.

I tend to treat them similar to others, in that every fourth waterng it gets flushed instead of fertiliser. However I have started to wonder if, with S/H I should be flushing, then toping up the resevoir with fertliser soloution. Currently I flush then leave plain water in the resevoir, then next time I'm ready for watering replace that with fertiliser solution.

Am I doing this right, or should I be leaving fertiliser solution in there after the flush? What do others do?

[Connie Star]

I'm not sure what the best answer to this is. My S/H pots accumulate a lot of salts from my well water. I usually flush with the well water after they've been in fertilizer for a few hours and then flush with distilled/rain water.
I'm not doing very well with S/H and I'm about to give up on it until I have an RO system in the indefinite future.

[Donaldbyrd]

I plug the holes with my fingers fill it to the top with my fert mix then let it drain out which flushes out the older water.

[zxyqu]

Hey Rosie, that's exactly what I do with mine. Once a month they get a flush with normal water, and then back to fert the next watering. Helps reduce some of the salt buildup with our city water. I'm sure an RO system would help that, and may reduce the need to flush clean, but I feel you have to flush it every now and then.

[RosieC]

Yeah, I thought (but may be wrong) that you needed to flush with plain water every now and then like you do with standard methods.

I do like Donaldbyrd when I'm fertilising and fill it to the top with fertiliser solution then list it out so that the old solution is replaced with the new. But every fourth time (ish) I use plain water, and a lot more of it, to try and wash away any build up in the Lecca.

OK, so I'm still not sure and there are a mixture of ideas it seems. I guess as they seem happy I'll keep doing what I'm doing for now

[RosieC]

Originally Posted by Connie Star

I'm not sure what the best answer to this is. My S/H pots accumulate a lot of salts from my well water. I usually flush with the well water after they've been in fertilizer for a few hours and then flush with distilled/rain water.
I'm not doing very well with S/H and I'm about to give up on it until I have an RO system in the indefinite future.

If the problems have been over the winter, it could be getting too cold. Just a thought but my Phals struggled in both plain Lecca and in S/H over the winter but loved it in the summer.

From what Ray has said, the lecca has high evaporation which causes evaporative cooling to be significant. If your house is already on the cool side over the winter then the additional cooling can be too much for warmer loving orchids.

I lost one NoID Phal and others were showing problems in the roots before I got a heat mat (and the weather was starting to warm anyway) and they seem happy again now. My cooler loving Encyclia which is in S/H didn't have any problem in the same conditions.

[Ray]

I use a dilute fertilizer solution at every watering; have not flushed with plain water in 15 years.

Cooling is only an issue if your evaporation rate is high - too little humidity, and/or too much air movement - AND you are growing your plants too cool to start with.

Mineral buildup occurs in all media, with the rate being dependent upon the combination of what is in your water (minerals already there plus fertilizers added), frequency of watering, and your evaporation rate. With organic materials, they decompose and we change them before it is a major issue. The tendency with inorganic media components is to forget that until it's too late.

Connie, I don't know exactly what issues you are having, but changing to RO probably won't solve them. I'd look elsewhere for the answer.

[Ray]

I'm not saying it applies to anyone in particular, but I find that folks that have issues with plants in semi-hydroponics seem to hit one or more of a relatively small range of shortcomings in their application:

• Improper timing of transplantation (a subset of this being they think it's a way to rescue ailing plants that they don't know how to grow). You gotta grow new roots that are made for the environment.
• Improper watering - don't fill pots to the top and allow the natural flushing action to take place.
• Let the pots dry between waterings - making it no longer 'semi-hydro" at all, just traditional culture in inert media. (Unless you flush periodically, minerals will build up rapidly with that type of treatment.)
• Grow their plants too cold - ignoring the evaporative cooling that the open, airy medium can foster. (Primarily an issue with phals, which folks seem to forget are really "hot" growers, but can be applied more broadly.)
• Another I'll throw in is the overall lack of understanding of what things "orchid culture" truly means, and the aspects it involves. ANY change in how you grow requires that you rethink the overall effects and interactions of all aspects, and many folks think "S/H" encompasses it all, rather than merely moisture delivery and avoiding medium decomposition.

[RosieC]

Originally Posted by Ray

Cooling is only an issue if your evaporation rate is high - too little humidity, and/or too much air movement - AND you are growing your plants too cool to start with.

Yeah, I was not clear that this is what I meant. In my case I winter phals a bit too cool anyway (simply because I keep my house pretty cool in winter), and that combined with low humidity in the house in the winter (due to the central heating even though it's only on low) is what I think lead to my S/H problems with Phals over the winter. My ones in bark go completely dormant in this time, but the ones in S/H started showing signs of root problems which seemed to improve again once I put them on heat pads.

[RosieC]

Originally Posted by Ray

I use a dilute fertilizer solution at every watering; have not flushed with plain water in 15 years.

Really interesting. I had thought they still needed a plain water flush. I will adapt my methods because it will be easier to remember if I just have to flush with fertiliser solution each time.