Dendrobium Seedlings just not growing

[greyblackfish]

Thought I would update with some good news. Keeping medium good and moist has paid off. New canes are growing in. Thanks everyone!!

The one that looks dire has not given new growth.

[Roberta]

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

[YetAnotherOrchidNut]

[QUOTE=greyblackfish;963514]
I use a powder fertilizer of 30-10-10, just the miracle grow brand off Amazon for $5. I usually make 1 gallon according to instructions and when it's time for feeding I dilute it down to half since I would rather feed a little less than more.[COLOR="Silver"]

Switch to better fertilizer, real orchid fertilizer that gives proper fertilizing instructions for a weekly feed. IMO fertilizer is one of the easiest things to change to improve your "game" instantly. Until you do drop the strength you feed your babies big time to something like 1/4 - 1/8th of the label strength, and make sure you pre-water before fertilizing. Powder fertilizer is more likely to burn your plants roots, and when they are babies they are *especially* vulnerable.

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.

[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

[estación seca]

Do some reading on the First Rays Web site about fertilizer. I calculate target nitrogen concentration in parts per million = miligrams per liter. At lower concentrations of nitrogen - say under 150 ppm - there is minimal risk of root burn for most orchids, excluding the cloud forest plants.

Fred Clarke writes on the Sunset Valley Orchids Web site that he fertilizes Cattleya seedlings with MSU fertilizer at a half teaspoon (2.5ml of powder) per gallon / 3.8 liters of water This is about 100 ppm nitrogen. He uses this at every watering, which may be 3 times per week during the warmest part of summer. He uses plain water once a month to wash out salts.

[greyblackfish]

Originally Posted by estación seca

Do some reading on the First Rays Web site about fertilizer. I calculate target nitrogen concentration in parts per million = miligrams per liter. At lower concentrations of nitrogen - say under 150 ppm - there is minimal risk of root burn for most orchids, excluding the cloud forest plants.

Fred Clarke writes on the Sunset Valley Orchids Web site that he fertilizes Cattleya seedlings with MSU fertilizer at a half teaspoon (2.5ml of powder) per gallon / 3.8 liters of water This is about 100 ppm nitrogen. He uses this at every watering, which may be 3 times per week during the warmest part of summer. He uses plain water once a month to wash out salts.

So mainly it’s about nitrogen content? I’m not sure how to calculate the ppm but I’ll check out the sites for some info.

I would have to see the ph of my tap water since I mostly just fill gallon cartons up with tap water and leave the cap off overnight so the chlorine will evaporate off. It’s just some general advice I’ve found on the internet, and as the saying goes, all information from the internet must be true. I have also seen somewhere that tap water has more minerals so fertilizer should be used even less. This I haven’t kept in mind.

Since the days are getting colder, I’m resolving to lay off on the fertilizer until next year. This will give me plenty of time to do my research. In the meantime my takeaway is that I should really be more mindful of my fertilizer and that just because the leaves don’t look like they hate me doesn’t mean the roots do.

Btw I fertilize my orchids twice a week at half the recommend strength and my cattleya get only once a month. I haven’t done the proper flushing for the sphagnum potted ones since I don’t want to waterlog them.

[estación seca]

There is a fertilizer calculator on the First Rays Web site. You input the N number on your label and you can find out how much to add to water to get a target concentration.

Tap water usually contains minerals. You can go to your water utility's Web site and look up the most recent Water Quality Report. This will give you total dissolved solids, a measure of the minerals in your water. If it is under 150-200 or so it should be fine for most Dendrobiums.

Dendrobium seedlings will grow all year if they are warm, bright and watered. You will get faster growth if you fertilize the in these conditions. Some kinds of Dens want to be warm, watered and fertilized all year. Others require a winter free of fertilizer.

[greyblackfish]

Thanks! I calculated my fertilizer is 30-10-10. At one gallon they ask for 1/4 teaspoon of powder putting me at 117 ppm. My water has 10 ppm nitrate so it’s 127 ppm if I keep it at the level instructed. Also the water ph here is alkaline at 8.25