Best orchid fertilizer , orchid fungus ...

[gore.m]

Hello
I have two questions :

What is the best fertilizer for orchids ?
I sometimes use slight dilution of cow-dung and special orchids fertilizer ... but I think they can grow faster

and related question :

I read somewhere orchids have some fungus on roots ... have they this fungus on roots automatically or it can be added ?
And if they have fungus on roots automatically , can fungus survive in indoor (flat) conditions ?

(I have some Phalaenopsis , Vandas , Oncidium , Epidendrum and Dendrobium)

Thanks you

[Team Ferret]

Good question on fertilizers. I do hope that answers come with reasons why one fertilizer is prefered over another. I am switching to MaxiGro (10-5-14), which is a hydroponic nutrient. It contains all primary, secondary and micronutrients. Now, I dont know if the 10-5-14 are the correct percentages for orchids, but I can always suppliment this nutrient with whatever I think it needs.

On the root fungi, it is called mycorrhizal fungi and there are many types. I am not sure if all types work with orchids, and if not I dont know which ones do. They do live in the root zone but only after exposed to the spores of the mycorrhizal fungi. There are several products that will add mycorrhizal to your root zone, or at least this is what they claim.

Mycorrhizal fungi is what is needed to germinate orchid seeds in the wild. This is because fungi break down decomposing matter outside of themselves and then absorb the nutrients. Since they dont absorb all of what they break down, the orchid seed or root will absorb the nutrients also.

Dave

[Ray]

Dave did a good job on the mycorrhizal fungi response, so I'll try to address the fertilizer question:

There isn't a "best" fertilizer. Here's why I say that:

• Plant nutrition requirements vary from plant to plant, so we would potentially need a formula specific to each one.
• The nutrition includes whatever minerals are dissolved in your water supply, furthering the need for a zillion different formulas.
• Temperatures and light levels can also play a role in nutritional needs.

That said, I believe that there are a general set of nutrients that all of our orchids need, so choosing a fertilizer that is complete with all of the known macro-, micro-, and trace elements is a good idea, but avoid one that's really high in nitrogen, as that tends to give you wonderful foliage, but no flowers.

I have been using the Greencare "MSU" formula at every watering for the last 3-4 years and am very happy with it. It's ratio's are similar to the MaxiGro stuff. I used Dyna-Gro "Grow" formula for years, and was happy with that, too.

Another thing to consider is concentration. Think of it in human terms: eat a complete-but-small meal a day and you might survive, but will not thrive. Increase the quantities and you'll be a far healthier individual (let's not go to the overfeeding part of the gradient, that get's too personal).

Fast-growing plants need more food than does a slow grower. Those in active growth need more that those that are resting. Because I have a varied collection of plants that are in every conceivable stage of growth and blooming (or not), I go with the general concentration recommended by the MSU study, about 100-150 ppm N at every watering.

If I lived in Florida or Hawaii, where the temperatures and light levels are higher, I'd probably increase that rate.

Then there's the pH, which can affect nutrient availability and uptake...

If you want to learn more, Dr. Bill Argo, inventer of the MSU formula, sent me PDF's of his 5-installment article about plant nutrition, and I have it on my website: Plant Nutrition

[justatypn]

Thank you Ray.

[Ross]

As a short testomony to what Ray says here, I read the stuff on his site and switched to a regimen with 125ppm nitogen MSU formulated for "pure water" with every watering (daily for many 'chids) and my Dendrobium anosmum (daily watering) is larger right now than it was when it matured the canes last year, at the end of the growing season. I am predicting at least 6" longer canes than best case scenario. This is just my experience. Of course everyone else is doing fine