fertilizer amount with K Lite

[Chicago Chad]

I have since started using K-Lite for all of my orchids. I was wondering what levels people are using this at when considering the plants are actively growing and in proper culture.

For starters, I am only using distilled water, so I have a 0 PPM start and 7.0 PH.I have a mixed collection. For my paphs, seedling to mature, I would like to increase my feeding amounts. I have been applying K Lite at only 75-100 PPM TDS (not N) over the Winter and I continue to use that amount on most of my miniatures. This is at every watering. I have started to increase that amount to 200-300 PPM/TDS, but it varies. I fluctuate the fertilizer amounts rather than flush my plants.

At what levels do you think the plants may respond well to? Carlos Fighetti mentioned that I could increase it much higher without problems. Any comments from experience?

 

[keithrs]

Lately, I started to water with about 100 TDS. Over the winter I very rarely fertilized. I see fine growth at these levels.

 

[Ray]

First I will comment that "TDS" is not an extremely good way of measuring and comparing concentrations. Yes, if you go from a TDS of 100 ppm to 200 ppm, you have approximately doubled your concentration. However, YOUR 100 ppm and Keith's 100 ppm are likely not the same in terms of true concentration, as there is just so much variability in meters (although at these low concentrations, they're bound not to be THAT far apart).

I have two TDS meters that I have tested with calibration solutions. With one, doubling the measured TDS actually doubles the true ppms. With the other, doubling the measured TDS results in 2.2X the true dissolved solids loading.

I think Carlos is correct that you could probably increase your loading significantly "without problems" - short term. However, if you feed frequently at high concentrations, you will find that the plants will stop blooming (excessive N).

I have been consistent at 50 ppm N, and am very pleased with the performance of my plants. In fact, many that have been quite recalcitrant for years are now blooming for me again.

 

[Rick]

I've been running a low K feeding program since May 2011, and the more I keep reducing the concentration (of all nutrients) the better it seems to get.

There are three factors in feeding. Frequency, concentration, and duration of exposure.

You can feed a little bit frequently (or continuously via hydroponic methods) or feed a lot at sporadic intervals (the old "weakly/weekly" principal).

For the last few months I've been pushing more and more toward tiny amounts on a daily basis, and everything from seedlings in compots to monster specimen Catts are doing great.

I just ran a batch of water through the lab (that I have been using on a daily or every other day basis.

The N (sum of nitrate and ammonia) is at 4-6ppm PO4 at 3-5 ppm.
Hardness at 30-55 mg/L( as CaCO3) and alkalinity at 15-20ppm.
pH - 6.5 conductivity is 75 - 120 uS/cm.
K should be about 0.5-1ppm in this mix.

Most of the base water I use is RO, but cut it about 10% with my hard well water. This is where most of the hardness and alkalinity is coming from, but also supplies about 15 ppm of SO4 at this dilution.

At least from an N and conductivity basis, this is pretty close to what the high end of stemflow concentrations coming down the trees in Borneo.

South American rainforest values seem to be even less.

 

[Trithor]

Rick, with daily watering, do your plants not remain too wet? What do you keep your humidity levels at if you are watering so frequently?

 

[Chicago Chad]

So by your calculator Ray I would use roughly .38 tsp per gallon to get 45ppm N in order to fertilizer miniatures such as Lepanthes everyday. The plants are mounted and about once a week I may water without fertilizer.
(Surprisingly that is about the exact rate that I have been using it without calculating it intentionally)

My questions are: if this is acceptable/ recommended during the active growing season at what level would you recommend for them during the less active months? (I know that this varies based on genus and species, but if you could layout some guidelines you have followed I would appreciate it.)

and,
At what level ppm N would you fertilize healthy paphs? Are you going to 125ppm N? I don't think I have ever intentionally fertilized at that rate. In addressing Rick's comment I water heavy and I pot loose with mixed media. I water every 3-4th day, never longer, just as the media 'approaches' dryness. So if my paphs look healthy is it OK to go higher during their active growing time.

and,
at what level have you seen evidence of fertilizer burn and on which plants? This is not something I have encountered yet, but nor have I tried to.

thanks for your insight.

 

[Rick]

Rick, with daily watering, do your plants not remain too wet? What do you keep your humidity levels at if you are watering so frequently?

Humidity is kept at 70% with a combination of wet wall ("swamp cooler") and fogger.

With about 2/3 or more of the collection in baskets and mounts, daily watering is appreciated.

As I've cut back on fert (especially K) even the potted stuff is doing good with frequent watering.

A lot of phrags are in some form of SH system so they are always sitting in a tray of water.

I only have 1 Catesetum and 1 deciduous Calanthes that get withheld water for the winter, but since low K (low everything really) I've greatly reduced the problems with root loss while increasing my watering rate by over 200%.

 

[Rick]

So if my paphs look healthy is it OK to go higher during their active growing time.

If they look healthy then what's the point? With high peaks in fert concentration, the only thing using it is the bacteria in the pots, which goes back to spending all your time on pot management rather than growing plants.

Like the aquarium example, you increase the feed rate more than what the fish can handle, you spend all your time and resources feeding and managing the filter rather than the fish.

 

[Chicago Chad]

The problem I have with some plants are that they grow very well, but do not bloom necessarily the same. From some other very experienced growers I noticed that they fertilized at a much higher concentration I have. They have had more success with some plants and the same for myself with others they have not. I was wondering that if my current culture is appropriate that if a change in fertilizer amount may trigger some to bloom as much as reducing in winter does for others. I fluctuate my feeding amount and I do not want to give them a dose that perhaps may be too high.

 

[Ray]

My collection is extremely varied, and I am too busy/lazy to cater to any individuals. ALL plants get fed and watered the same, pretty much constant all year long. The variation being in frequency, which is determined by the weather.

I don't think that a 200 ppm N solution would be damaging, but you have to understand that the 200 ppm N becomes 2000 ppm when 90% of the water has evaporated. (Actually, not knowing the specific solubilities of the ingredients, I don't even know if 2000 ppm N is possible, but you get my point.)

Like Rick, I try to keep things pretty much constantly moist, precluding any concentration issues.

 

[Rick]

The problem I have with some plants are that they grow very well, but do not bloom necessarily the same.

Success is in the eye of the beholder. I realize that we generally grow orchids for the blooms and not the foliage, but after 12 years of growing I've ceased to worry about plants that grow well but not bloom, since I've lost enough plants that "bloomed themselves to death". I also keep hearing from the folks that show a lot of plants that getting an AOS award on a plant "is the kiss of death" for that plant, and then they go on to list all the awarded plants (quality awards, not cultural awards) they "used to have". So far I still have all my awarded plants, but a few were touch and go for a while before I went to low K.

Read through the thread on SlipperKing's Paph parishii. This is frequently cited as a slow growing species, that seems to bloom on plants much smaller than observed in the wild. There are very few in collections because most people rarely have them (blooming) for more than 5 or so years. Either that or they linger for decades never doing much of anything before they die.

You could also read the thread I started on my Cattleya gaskeliana. This is a large aggressive growing specimen Catt that has never failed to bloom every year since I've had it. And in the last year it's never received a feeding of more than 50ppm N.

I've brought up the little old lady in Shelbyville TN several times who NEVER fertilizes. She used to operate a 7 greenhouse cut flower business in the 60's and 70's (mostly Cattleya corsages), but has since cut back (she's in her 80's) to 5 greenhouse and hobby growing. There never any shortage of blooming stuff in her GH's and most of her plants are huge specimen plants.

I know this is counter to 90% of the growers out there, but I'm just not seeing any real gains from heavy fertilizing.

I could also switch to the agriculture literature with a paper I recently came across on alfalfa culture and potassium use. Alfalfa is considered one of the highest K use plants out there (more than corn).

In a California study, potassium was applied at the rate of 0 to 800 lb/acre (either as KCl or KSO4). The unamended soil was rated as "low" for background K levels.

The field was cut multiple times during the growing season, and assessed for total yield and protein content of the alfalfa.

The yield over the various treatments was not significantly different. All treatments from 0-800 lb applications produce around 6 tons/acre. However the protein content of the alfalfa declined (significantly at the highest application) with increasing K application. So even a plant with a reputation for wanting lots of K wasn't improved upon with any more than the background available K. Maybe they needed to play with N and P instead? but 6 tons per acre was nothing to sneeze at in the first place. So why waste nutrients??

 

[Chicago Chad]

Rick I agree that it is more to focus on the plants overall health rather than flower production. I also agree that cultural awards have more substance to them and in my opinion 'mean more'.

The problem is when I have a plant like one of my cuthbertsonii's. It has more than 60 growths in a 2" clay pot. It is like an ice cream cone of lush green. Unfortunately it only has one bud. Last year it had only a few as well. I know that the plant could benefit from a more pronounced diurnal range to help induce flowering, but that is more difficult to provide than an increase in fertilizer.

Granted the increased amount in fertilizer will never make up for or account the cultural or mechanical necessity of temperature variations, but I thought it may help a touch. This is one of many examples. My fear is that if the plant continues to be treated under the same conditions, it will do as it had. Grow great-flower little. I grow orchids with many goals in mind, one that remains consistent is a heavy onset of blooms. This can be more frustrating for me with a plant that does well compared to one that does not.

 

[Rick]

The problem is when I have a plant like one of my cuthbertsonii's. It has more than 60 growths in a 2" clay pot. It is like an ice cream cone of lush green. Unfortunately it only has one bud. Last year it had only a few as well. I know that the plant could benefit from a more pronounced diurnal range to help induce flowering, but that is more difficult to provide than an increase in fertilizer.

That's a great problem to have!! Also you mention cuthbertonii (plural) what are the others doing?

You might try increasing the duration of your lights. Rather than increasing the total amount of fert (higher N just gives you lots of growth rather than flowers anyway), bleed in a little more PO4. Cut your K lite with a dash of one of the "bloom boosting" ferts like the the Dynagrow Bloom booster with Mag. That has relatively low N and K but plenty of P.

I have a couple of bulbos that are like your cuthbertsonii. I made a concoction similar to the Dynagrow product, and after a month I just found a couple spikes! But that could be totally coincidental/anecdotal. It certainly hasn't hurt.

 

[Chicago Chad]

Thanks Rick. I have not used a feeding of any bloom boosters this year, because I had run out and not restocked. I did move it up, much closer to the light last week. It has already put out a bud, so light intensity may have been the issue.

When a plant is growing well I have a difficult time discerning between the need for more light, fertilizer or both. If I grow a plant well for two years, knowing that it is blooming size and it does not bloom, I try and readjust what I can.

Along with this cuthbertsonii, the others a much younger in my collection, but are growing well. They all bulk up and to be honest I should not complain. I may just be a little impatient.

Regarding bulbo's: I see this more with them than any other plants. I have a wightii and a frostii that put on 14 bulbs last year without a single flower. I will give them until fall and then they may have a new home.

 

[Rick]

When a plant is growing well I have a difficult time discerning between the need for more light, fertilizer or both. If I grow a plant well for two years, knowing that it is blooming size and it does not bloom, I try and readjust what I can.

Regarding bulbo's: I see this more with them than any other plants. I have a wightii and a frostii that put on 14 bulbs last year without a single flower. I will give them until fall and then they may have a new home.

Trying to become "one with our plants" is the never ending challenge in orchid growing. The other part of the challenge is to not fear to try changing things and then the patience to let a change take effect.

My frostii is a pretty regular bloomer, but it's in a fairly bright spot. My stingiest is a grandiflorum and a sulawessii. The grandiflorum is bigger than a basketball. I've had it for 6-8 years, and I know there has been 2+ years between blooms sometimes. The sulawesi has never bloomed in the 5 or so years I've had it although it grows very well too. I have it up next to blooming Vanda's so it should be getting enough light.

Fortunately I have lots of other plants packed into the GH to distract me from the handful of stubborn plants. They'll bloom eventually.