Question about fertilizer
 

Morning, all! :)

I remember reading somewhere on this board not too long ago (it may have been an old thread - I spend a lot of time googling) that someone switches their fertilizer ratios at a certain time of year which signals to the plant that it's time to bloom? Or should?

I have been feeding my guys a fertilizer that is 30-10-10 because I read that plants potted in bark need more nitrogen...but I have also read that too much nitrogen in cattleyas keeps them from blooming...? Does this apply to other orchids? Is it even true?

If it is, what kind of fertilizer should I switch to so as to allow them to bloom, and when would I know when it's appropriate to do so? My cattleyas and one of my mini phals are in active growth right now - so is that when they need a switch? Or is it later when they're fixing to bloom? How do I even know when they are trying to grow blooms? (This is my first year with orchids, so)

Thanks!

Excessive nitrogen can really push foliage growth, but can also negatively affect blooming. However, that has more to do with the mass of nitrogen applied than to the ratio of the specific formula.

Secondly, there is no fertilizer that promotes blooming. A healthy, well-grown plant will bloom to its maximum genetic potential; nothing will make it perform better.

If one uses 1 teaspoon of 30-10-10 per gallon, they will be applying about 375ppm N. If you switched to Dyna-Gro "Grow" formula (7-9-5) and used it at 4-1/3 teaspoon per gallon, that would also be about 375 ppm N, and if used regularly and frequently enough, I doubt much of anything would bloom in either case. If, on the other hand, you used it at the same teaspoon per gallon as the 30-10-10, you'd only be feeding at about 85-90 ppm N, and the plants would likely do much better.

So what should I switch to in order to make sure they bloom AND grow?

Like Ray says, there aren't any fertilizers that make an orchid bloom. Some orchid growers theorize that they should provide more nitrogen during the growing season because nitrogen is important for growth and that they should provide less nitrogen and more phosphorus and potassium during the blooming season because those elements are used by the orchid to produce blooms. There isn't a lot of evidence that that approach works better than just providing all the elements that the plant needs all year long. That would mean that using a more balanced fertilizer all year long would provide the nutrients for both growth and blooming. If you occasionally want to use a high nitrogen fertilizer during the spring and summer growing season and occasionally use a bloom booster fertilizer in the fall and winter, I'm sure it won't hurt anything.

---------- Post added at 12:21 PM ---------- Previous post was at 11:08 AM ----------

To answer your specific question, you can use something like Dyna-Gro Grow which is a balance fertilizer with all the micro-nutrients, including calcium and magnesium which I think are important.

If you want to finish using your 30-10-10, in the fall, when the growing season is ending, use your fertilizer less often. Maybe half as often as usual. That will decrease the total amount of nitrogen the orchid is getting so it won't be inclined to continue growing new leaves and not blooming.

Okay, I will have a look at Dyna-Gro, thank you. If I were to switch would it have any impact on the plant now or would it just be like "Oh, less nitrogen but more potassium and phosphorous..cool!"

I bought the fertilizer I had when I got my first ever orchid and the box said "orchid fertilizer" on it...derp! I have been researching them more recently and realizing it's the wrong thing lol.

Don't think of it as the wrong thing. You're giving the plant the nutrients it needs. It's just that there might be slightly better options. The fertilizer you have is probably fine during the spring/summer growing season. But orchids don't need so much nitrogen in the fall and winter when a lot them bloom rather than grow. Either using the fertilizer a little less often or using a fertilizer with less nitrogen will be more beneficial in the fall and winter. Using a balanced fertilizer like Dyna-Gro all year long is just a little easier to manage than changing fertilizers during the year. I've used many, many different fertilizers over the years and I have not seen a whole lot of difference in my orchids. What ever you use try to get one that includes micro-nutrients and, in my personal opinion, one that has calcium and magnesium. Dyna-Gro Grow is just one fertilizer that meets that criteria. Switching fertilizers shouldn't have any bad affect on your orchids.

I noticed that Dyna-Gro had an "orchid plus" or something, but its ratios are different than the "grow" one..is there one that is more preferable than the others? And is there a reason that the numbers are so low on that formula? (As opposed to, say, 13-5-15 or 20-20-20)

Also, I have some KelpMax from Ray that I have been alternating every few weeks instead of fertilizer...should I use more/less of that? As I read it, it was just as a supplement to fertilizer, not a fertilizer itself..correct?

Kelp products, like KelpMax, are excellent for orchids in my opinion. Ray could give you more information on KelpMax. But that kind of product is a supplement and not a fertilizer. It provides plant growth hormones and some micro-nutrients and it will usually lead to better root production. You still need to apply your fertilizer on regular basis. I don't know the difference between Dyna-Gro Grow and Dyna-Grow Orchid Plus. I've used Dyna-Gro Grow quite a bit but I have never used the Orchid Plus. I'm sure either one would be fine. The numbers are lower on Dyna-Gro because the nutrients are less concentrated. Just use it according to the label.

If I'm not mistaken, the numbers on fertilizer are ratios. For example, you're 30-10-10 is really 3-1-1.

The N-P-K numbers are percentages by weight. So, if you were using 1 gram per gallon of a 30-10-10 then to get the same NPK concentration using a 3-1-1 you would use 10 grams per gallon. Since the NPK numbers are percentages they are also ratios.