When to fertilize with blooming fert?

[KC Kam]

Greetings All,

All these while i have been fertilizing only with a balance 21-21-21 fert and have never used any blooming fert. I guess my plants are strong enough to have more blooms now, therefore i would like to start to apply blooming fert.

Anyone can advice when to fert them? Should i apply before they develop buds, when they starts to develop buds or i should just fert them alternately between balance fert and blooming fert?

Is this there any difference in fert timing between cattleya that blooms all year round and dendrobium anosmum that only blooms once a year?

Please advice.


Thanks.

[Roberta]

If the plants are healthy, they'll bloom. Messing with different fertilizer formulations is a waste of time and money. If the plant wants more of something than something else in the balanced fertilizer, they'll take what they want and leave the rest. They don't need much of any fertilizer, so just use the dilute (1/4 to 1/2 of what it says on the bottle) except during the rest period of those orchids that need it, when they don't need any at all. In your warm climate, I expect that few, if any, need a rest period (which is more typical of orchids that grow in cooler climates, and may have a time when it also doesn't rain)

[Swimmingorchids]

i'll second what roberta says. Your nutrient is well balanced so the plant will get everything it needs - it might show a deficiency which is highly unlikey, till then just stick to your regular fert all year round.

Some will argue that messing with the ratio will encourage bigger flowers or more flowers but the problem is nobody really knows the right ratio and all other parameters need to be perfect for it to make any difference.

[Ray]

Expanding upon Roberta's and Swimmingorchids' posts, in truth, there is no fertilizer that "boosts" blooming. That whole concept came about either as a misinterpretation of data or as a marketing myth (or both).

When the first "chemical fertilizer", Miracle Grow 30-10-10, was developed at Rutgers University and marketed, folks poured in on heavily. Their plants grew great, but after a while folks started noticing their plants not blooming as well as they had in the past. Another formula was developed, having decreased nitrogen and enhanced potassium, and - Lo! And Behold! - reasonable blooming levels returned. That formula, therefore, was marketed as a "bloom booster".

What folks didn't grasp (or possibly admit) was that it was the excessive application of nitrogen that had suppressed the blooming, so the second formula didn't actually "boost" anything, but by diluting the nitrogen content, it no longer suppressed it, allowing the plants to bloom normally.

The facts are that, while nitrogen is - by far - the most important mineral nutrient, a plant doesn't need very much of it - about 5g of NPK (90+% of that being N) and around 100kg of water are necessary for a plant to gain 500 grams of mass - and that given that minimal amount of nutrition and the proper culture, a plant will bloom to its genetically-programmed maximum capabilities. Any shortfalls detract from that.

[SouthPark]

Originally Posted by KC Kam

Anyone can advice when to fert them?.

A general rule of thumb that I agree with, that people often teach is - relatively low doses. It's a general rule of thumb.

On the bottle of fertiliser for orchids, they usually provide recommended dosage. And I tend to favour going well below the supplier's recommended dosage. For example, the supplier might say 5 ml per litre. So, instead of that, could go 2.5 ml per litre, or 2 ml per litre ..... even less.

And then there's the question of when to fertilise. This is assuming a well draining pot and media. For me, I now fertilise by watering my volcanic rock media (with fertiliser mix solution - relatively weak concentration) once per month.

Actually, I use a wand weed-sprayer for watering ...... so whenever it is fertilisation time, I just add my yates orchid food solution (that's what they branded it as --- or something like that) to the weed-sprayer container (with water of course). Weak concentration fertilisation.

I only water the roots and media ----- watering them well. I found no problem with watering rhizome of my catts ----- as there's good air-circulation over here, so rhizomes will dry out nicely here. The nozzle is set to a wide enough spray pattern, and I use enough pressure so that water comes out at a good fast rate - otherwise, watering the orchid would take ages. If there's any water left over in the container, I just leave water is in the container, then add more water to it ---- for next day watering. I also leave the spray container of water near the plants - in the same area - so that the temperature of the water is roughly the same as the plant's temperature ----- just in case. So the next day, I just carry on watering. And then keep watering.

Then two weeks later ----- I do the same thing - not with fertiliser ------ but with cal-mag solution. Relatively weak concentration. Same weak concentration trick used. Any left over water in my container just gets topped up, so the plants get really weak treatment the following days.

So basically - my approach is fertilise, then do cal-mag treatment 2 weeks later, then fertilise 2 weeks after that. Times in-between will be pretty-much regular watering. So ----- my approach has been once a month fertilising.

I choose once a month, which is better than none ---- because I grow a dendrobium discolor and angraecum eburneum in pure volcanic rock pots - under some small fig tree, but they do get full sun for a lot of time during the day ----- which have never once been fertilised (not manually that is). Lawn sprinkler just keeps them wet - been growing there for 30 odd years, in the same spot ---- but now big and wild. And they flower excellently. So when they tell us that orchids don't need much fertiliser --- I definitely believe that.

For some plants, I stop the treatment during times where I notice slowing down or stopping of growth ----- like Fdk./catasetum type plants.

[Roberta]

To add to Ray's post - easiest way to reduce nitrogen is to just reduce fertilizer. The orchids really don't need the rest of the formulation - Ray has found that a low-potassium (K) formula (K-lite) works fine for him, and most of the phosphorus got added to supply phosphoric acid to adjust pH, not add to the nutrition particularly. So just reducing (or eliminating) fertilizer when the plant isn't growing much is easier (and cheaper) than maintaining an inventory of formulations that don't really contribute much anyway. Think of fertilizer as "vitamins" not "food"... the "food" part is carbohydrates, from photosynthesis. Slow-growing orchids don't need much in the way of vitamins.

[KC Kam]

Hi all,

Thank you everyone for your precious advice.

[SouthPark]

Originally Posted by Roberta

Think of fertilizer as "vitamins" not "food"... the "food" part is carbohydrates, from photosynthesis. Slow-growing orchids don't need much in the way of vitamins.

That's definitely food for thought!

I like the idea of considering the fertiliser as being vitamins. I guess that food is substance intake required for the plant or animal to grow nicely. For an orchid, that could be the carbo and fertiliser and cal/mag. But considering fertiliser as 'vitamins' is quite good.

[Roberta]

Glad you like the analogy. Another note is that orchids are very efficient at recycling tissues that are no longer needed (like old flower spikes) even further reducing the amount of outside minerals and trace elements needed. Their epiphytic environment is very nutrient-poor and they have evolved to live and thrive there. That's why I don't rush to cut off old flower spikes if they are not in the way or too ugly, and likewise firm but leafless, rootless old pseudobulbs. The plant can utilize them.

[Ray]

This has turned into a really good discussion!

"Recycling" of nutrients, including transferring them from living tissue to newly-growing tissue when external supplies are deficient, is quite efficient with most, but not calcium. That's why a decent, constant supply is important when plants are actively growing.

Most tap water supplies have plenty, and it is possible to overdo it, so I think it's a good idea to have some idea of the chemistry of your water before adding more.

As to the nitrogen loading, I wasted many years thinking that "high nitrogen" was a matter of the fertilizer ratio, but as Roberta wisely stated, its the amount applied that counts. It is possible for example, to overdo nitrogen with a 3-15-10 formula (any formula containing N), yet by keeping my application concentration low, I do not do so with K-Lite, a 12-1-1 formulation.

Fertilizer is important, but not all THAT important. An orchid is about 95% water. Of that remaining 5%, about 95% is carbon, oxygen, and hydrogen, obtained from the air and water. Of that remaining 5%, about 80% is nitrogen from fertilizer and that remaining 1% constitutes all of the other nutrients, combined.

The upshot of that is that if you focus your attention on finding a way to grow your plants that allows them to be watered heavily and often without suffocating the roots, that will do more for them than anything else. Add a tiny amount of fertilizer, and they'll be very happy.