Experiment Using Bonsaify 80/20 Perlite/Peat Substrate

[mrcasey]

I love Eric Schrader's Bonsaify you tube channel - some of the best content out there. I'm trying the suggested 80/20 mix of perlite/peat potting mix for my jbp seedlings. He uses coco coir for the organics, but wrote that peat would be ok. As you can see the seedlings in regular potting soil look to be doing much better. The plants are under grow lights and have been chugging along for about 8 weeks. I've used miracle grow fertilizer and recently added iron and other minerals to combat the chlorosis in the heavy perlite mix. Eric gets great results - anybody have an idea what I might be doing wrong?

 

[WNC Bonsai]

More recently @Eric Schrader said he had stopped using coco coir in the mix and went to pine bark (as I remember) as the organic fraction. Hopefully he will chip in on this one.

 

[RoadManDenDron]

I wonder are you feeding and watering these the same?

The perlite heavy mix will hold much less water and nutrients than the organic mix

 

[mrcasey]

I've been fertilizing with full strength miracle gro every 2 weeks. I also added an iron supplement with other minerals. I've noticed with peat-based substrate, that water seems to wick throughout the container, but with aggregate substrates, the surface dries out completely and leaves a small water table remains at the base of the container.

 

[bonsaibandit]

Maybe it has something to do with the age of the pine seedlings. For instance 1st year seedlings (which I am guessing yours are) may need a moister environment and would therefore do better in the potting mix, whereas seedlings that are 3-4 years old and more established, may need a dryer mix for root health. Just an idea though, I have never done a side by side comparison myself. I generally buy JBP seedlings that are a few years old and they have done great in pond baskets with a 75/25 perlite/coco coir mix. It could also just be environmental difference specific to where you live.

 

[Glaucus]

I was surprised to see his results for pine seedlings in 80% perlite. But, he carefully documented what he did.
This seems like a fertilizer thing. Maybe his 20% has more fertilizer or CEC than your 20%?

The more substrate, the more you need to be on top of your fertilizer game.
For seedlings where you want to develop them rapidly, you shouldn't need a 100% or 80% substrate mix.
Perlite has a lower CEC than things like akadama, lava rock, or pumice.

 

[RoadManDenDron]

My advice would be to try half strength weekly on the perlite seedlings

Maybe even full strength on a couple because it is most likely mostly washing away

2 weeks seems like a very long time between feeds for such a high perlite mix, which is closer to hydroponic growing.

Separately I am wondering if the moisture retention at the bottom of your containers is the bulk of the peat that has washed down as the perlite has floated up to the top? This would leave the rest of your container with very little CEC