Feeding at 25ppm N/K-lite…?
 

I’m getting back into growing orchids after an 18 year absence, growing outside in a small shade house along the No California coast.

After much research I’ve decided to feed with K-lite from Ray, distilled water, at 25ppm N, at most/every watering. Ideally with a pH of 5.8-6.5.

This is radically different from my former growing experience (in a green house) where I fed (with Dyno -Grow) more like 200ppm N during active growth (and pretty much ignored pH), flushing crazily in between feedings. Doing this I had great success growing/blooming Catts, Oncid alliance, Phals…

The whole 25ppm N, as well as the K-lite 12-1-1-10Ca-3Mg formula, at every feeding sounds logical (natural) to me, but it does make me nervous. Would very much like to hear from those that have implemented this weak but frequent feeding regime and your experiences…

I've been flushing/feeding all my Orchids DAILY with a similar weak feeding. I keep my PPM between 50 and 60 PPM for the everyday flush/feeding. I began the daily schedule after much research, and much more thinking. If our goal as Orchid growers is to emulate Mother Nature, then a daily rainfall in their environment would suggest we provide a daily flush in our home setting. My Orchids are a mix of mounts and Semi-Hydro. Not a single pot with bark, NONE. They are all growing roots and shoots like crazy. Do not be nervous with this technique, as it has been time tested by many.

I originated that fertigation regimen back when I had a greenhouse with RO tank and metering pump. Now that I feed manually, using a hose-end sprayer, I have returned to 100 ppm N weeklly. Both - and other methodologies - are perfectly valid techniques.

Your desire that the solution be between pH 5.8 and 6.5 will probably not be met. It is likely to be lower, BUT IT DOESN’T MATTER. For one, it is a very weak acid, so won’t buffer worth a damn. Second, the pH of the applied solutions play an extremely small role in the pH of the rhizosphere, and that’s what’s important.

The plant itself is the biggest controller of pH, with the medium and their contained microbes following close behind.

I used to be very careful to get my fertilizer solution at 6.0, as I figured the inert LECA is used wasn’t going to affect it at all. I metered Dyna-Gro Grow formula with one pump, ProteKt (primarily a KOH solution) with another to do so.

What I found was that right after watering, the pH in the S/H reservoir was 6.0, but depending upon the length of time after watering and the time of day, the pH could be anywhere from 3.5 to 8.5. AND THE PLANTS WERE FINE.

Keep in mind that pH is a measure of the ratio of H+ and OH- ions in the solution. If there are 500 of one and 300 of the other, or 5 million of one and 3 million of the other, the pH is the same, but obviously that second will be a much stronger acid or base, so could be damaging, while the former won’t be.

I fertilize with K-lite everyday at 25-50ppm. No need to flush.

I’ve not heard that before—you don’t need to flush when dosing 25-50ppm? That’s a time-saver…

(I’ve enjoyed your Catt vids, Stephen. Your use of zip-ties as supports is creative and I think I’m going to emulate that with some of mine)

The flushing is only necessary if the fert uses urea as the nitrogen source. If this is not the case, no need to do it.

If the potting medium never dries out, there will be no precipitation.

Any dissolved solid, including whatever is in the water to sart with, will build up if the solvent (water) evaporates.

Same here. No fert buildup, even on my terra cotta pots. I don't fertilize during the winter.

I've never noticed any sort of build up at that level, in either my plants outside (which do admittedly get rained on, typically in spring and fall) or in my cabinet (that doesn't receive rain, as you can imagine).

Thank you! Zip ties really are incredibly helpful!

I also don't fertilize in winter, so maybe that could count as flushing?

I’ve been doing k-lite at 25PPM for a bit over a year now with most every watering. No signs of fertilizer burn ever. The only time I don’t fertilize is when I apply Kelpak/quantum total once a month. Some of the standard Catt’s put out absolutely huge growths this year. Many are in sheath now, with a couple beginning to fill the sheaths. Had one of my C. harrisoniana put out three growths this year, which is about triple what it normally does. I think you’ll be happy with this fertilization rate.