Dendrobium Seedlings just not growing

[greyblackfish]

Originally Posted by Roberta

Look more closely at the "dire" one. I see a new little growth on the right side of the somewhat-shriveled pseudobulb. Patience!

I'm sorry I didn't even get notified of this post. I poked around recently but still nothing. I'll just be patient and maybe some day it'll do something

Originally Posted by YetAnotherOrchidNut

A bunch of my older plants have visible signs of root burn from when i used exactly the same 30-10-10 you are, I switched to a high quality fertilizer from an orchid grower ("Orchi-Fit") and my plants almost instantly responded and none of my new plants have been burned. A friend still uses the chemical fertilizer and when we purchased some baby orchids together he managed to severely damage the roots on some of his babies whereas mine are fine.

30 is the nitrogen level some recommend for pure bark adult plants after pre-watering, the idea being that natural bacteria deplete the nitrogen as they break down the bark, so you provide extra so the orchid gets some. But IMO even this is a little debatable, a lot of folks use 10-10-10 or weaker for bark media. Orchi-fit is 7-7-6 I think.

Wow, I have read that fertilizer is less than necessary and are all about the same. But that's a pretty strong argument from you.

I'm not even familiar with the concept of root burn. But with a quick Google, I do see that some of my orchids do have the brown burn look. Well anything is worth trying out once. I will try a different fertilizer with weaker strength. I didn't really think about different mediums making a difference.

[YetAnotherOrchidNut]

Originally Posted by greyblackfish

Wow, I have read that fertilizer is less than necessary and are all about the same.

Basically that is an oversimplification. It is true in the sense that Urea is Urea and it doesn't matter where you buy it from, it will be an equivalent source of nitrogen for your plants. It is not true in the sense that different fertilizer manufactures use different mixes and sources for their formulations (eg Ammonia Nitrate instead of Urea) and those decisions can affect the way you use the fertilizer to feed your plants. Some fertilizers may burn your roots if you don't pre-wet them. (Urea based fertilizers have this reputation.)

A bespoke custom orchid fertilizer from a reputable source will likely contain a cocktail of chemicals from different sources, probably some organic, micro nutrients, and maybe nano-nutrients all tailored to your plants specific needs, and it might even include kelp extract or other materials which encourage a healthy plant. Kelp extract for instance is known to promote more vigorous roots and branching of roots.

Another point is a bespoke orchid fertilizer will likely have been well tested at the stated dosages on /orchids/, thus you are more likely to use the right amount. Most generic fertilzer have instructions like "1 gram per liter, every 3 months" which might be suitable for roses in a garden bed but is totally wrong with an orchid where the rule of thumb is "water weakly weekly". Eg, use very low strength fertilizer, but use it all the time (except when you flush).

Anyway, i recommend you do a bit of research. I have seen mention by reputable people of MSU fertilizer for instance. Reading some info on it I see it says "Fertilizer is recommended for use with reverse osmosis (RO), rain or tap water low in alkalinity", if that describes your situation then maybe try it.

Originally Posted by greyblackfish

I'm not even familiar with the concept of root burn. But with a quick Google, I do see that some of my orchids do have the brown burn look. Well anything is worth trying out once. I will try a different fertilizer with weaker strength. I didn't really think about different mediums making a difference.

Don't forget that there are two concerns here, how dilute your fertilizer is, and what the ratio of N to P to K. Some folks recommend 30-10-10 for bark orchids, a lot of other folks recommend 10-10-10. What pretty much everybody agrees on however is it should be very dilute whichever you choose, and when in doubt pre-water before you fertilize.

[greyblackfish]

Originally Posted by YetAnotherOrchidNut

Basically that is an oversimplification. …Some fertilizers may burn your roots if you don't pre-wet them. (Urea based fertilizers have this reputation.)

Anyway, i recommend you do a bit of research. I have seen mention by reputable people of MSU fertilizer for instance. Reading some info on it I see it says "Fertilizer is recommended for use with reverse osmosis (RO), rain or tap water low in alkalinity", if that describes your situation then maybe try it.

Don't forget that there are two concerns here, how dilute your fertilizer is, and what the ratio of N to P to K. Some folks recommend 30-10-10 for bark orchids, a lot of other folks recommend 10-10-10. What pretty much everybody agrees on however is it should be very dilute whichever you choose, and when in doubt pre-water before you fertilize.

Yes very true you are. I have noticed that I have a cattleman walkeriana with some new roots that were stunted in growth and some brown discoloration on a zygopetalum. So it might have been better not to have used fertilizer at all in some cases. And since I’m assuming most orchid fertilizer is for ones potted in bark. My phal is doing pretty good with it.

Anyway, I will put more research into this topic. I feel like probably my tap water is gonna be more alkaline than other places. I’ll have to run a water test.

Thanks for the advice. Great information